Many people who try to become more balanced about their eating find themselves faced with a host of psychological and physiological obstacles that interfere with their success. Some of these obstacles result from the changes caused by an eating disorder, while others are a function of normal physiological processes. Encountering these obstacles can lead to a sense of confusion, frustration and in some cases futility. Without a proper understanding of how the body functions, many people become too frightened to attempt any further changes in their eating, even though they want to. The following information is provided to help those people cope with a body that has become for them "questionable." By finding answers to their questions about how their body functions and learning what can be reasonably expected of it, such individuals can be more successful at balance.'
We need to eat because our bodies are unable to provide for themselves the energy to support the physiological functions that maintain life. Energy is needed to accomplish various tasks, not all of which are apparent to us. Some work that our bodies do is outwardly visible, such as walking, lifting a box, or skiing. Even mental work, such as studying, requires energy. Less obvious is the energy expended by the body at rest. Only about a third of the average person's energy expenditure is for obvious work. The other two thirds are required to maintain the body's internal functions and for metabolism itself. This latter, more primary portion of energy expenditure, is known as the Resting Energy Expenditure (REE). The Basal Metabolic Rate (BMR) is defined as the REE upon awakening, at least 12 hours after the last meal. This makes it lower than REE by about 10% but the two figures are often used interchangeably. Resting energy is expended when the heart beats, the lungs filter oxygen, the kidneys filter the blood, the body keeps warm, and when the various nerves and muscles generate electrical activity even when resting. There is also a continuous biochemical reaction occurring as the body metabolizes and transports the various nutrients that have been previously consumed.
There are hunger and satiety centers in the hypothalamus of the brain that stimulate us to begin eating and to stop eating when we have satisfied our needs. Hunger involves a complex interplay among at least five known factors: blood levels of glucagon in collaboration with insulin, quantity of stomach contents, current weight in relationship to healthful weight, the body's need for essential nutrients, and thirst. Hunger can be influenced by any significant variation in a person's schedule of eating that has accustomed the body to expect food at particular intervals. In addition, the typical quantity of food consumed at these times can affect satiety levels by determining what the stomach can comfortably contain as well as the point at which satiety level is reached. Appetite, in distinction from hunger, involves both physiological and psychological dimensions including our particular food preferences or emotional reactions to food. Therefore, it can override hunger.
There are five basic categories used by nutritionists to classify the types of nutrients our bodies need. These are carbohydrates, proteins, lipids, vitamins and minerals. The first three are macronutrients and constitute the bulk of what our bodies use to provide energy to maintain proper physiological functioning. The latter two are micronutrients and are needed in smaller but no less essential amounts. Some specific nutrient groups can be supplied by other groups due to biochemical changes that the body performs on them. For example, carbohydrate can be formed, albeit less efficiently, from protein. However, protein and some essential fatty acids cannot be synthesized from other nutrients and must be consumed.
Carbohydrates are a complex molecule of carbon and water (hydrated carbon) which in conjunction with oxygen, are burned by the body as fuel. It is the chief source of energy for all body functions and muscular exertion as well as assists in the digestion and assimilation of other foods such as proteins and lipids. Carbohydrates are classified as either sugars, starches or cellulose. All sugars and starches are converted by digestive juices to a simple sugar called glucose. Some of this glucose or "blood sugar" is used as fuel for the brain, nervous system and muscles. A small portion of glucose is convened to glycogen and stored in the liver and muscle, with any excess converted to fat and stored throughout the body as an energy reserve.
Cellulose, found in whole grains and in the skins of fruits and vegetables, is largely indigestible. It provides little energy in the diet but does provide bulk that is necessary for proper intestinal action and elimination. Fiber increases the feeling of fullness and so can help diminish appetite. Fiber-rich foods may block absorption of some of the calories contained in them, thereby decreasing the possibility of weight gain.
Simple sugars, such as those found in honey and fruit, are very easily digested, providing energy and some other nutrients. Double sugars, such as sucrose or "table sugar," provide energy but lack any other nutritional value and so are considered an "empty" source of calories. Over time, ingestion of large amounts of refined sugar can lead to a "nutrient debt" wherein a person has sufficient energy to fuel the body, but lacks other essential nutrients. This can lead to being overweight but undernourished.
Complex carbohydrates called starches are metabolized more slowly than sugars so provide a more prolonged source of energy than simple sugar. Some complex carbohydrates, however, may release energy more quickly into the bloodstream, causing the same type of blood sugar drops as refined sugar. Combining such foods with a more slowly digested food, e.g. protein, can diminish this effect (see Appendix A). Since starches, such as grains, are typically accompanied by other nutrients, including protein, vitamins and minerals, they are "nutrient rich" and should compose the bulk of a well balanced diet.
Lipids (fats and oils) are a complex molecule of carbon and hydrogen (hydrocarbon) which, depending upon the arrangement of carbon to hydrogen atoms, are considered saturated or unsaturated. Saturated fats tend to be solid at room temperature and are usually found in animal products such as meats, butter and some dairy products. Unsaturated fats tend to be liquid at room temperature and are derived from vegetables, nuts, seeds and fish. Vegetable shortenings and margarine have undergone a "hydrogenation" process to solidify them. This creates a byproduct of trans-isomers that may promote heart disease and cancer.
Lipids or fats are the most concentrated source of energy in the diet providing 9 calories per gram as compared to 4 calories per gram from carbohydrates and proteins. Fats are digested more slowly than carbohydrates and so provide a longer-lasting feeling of fullness and satiety after a meal. Compared to carbohydrates, however, lipids require fewer calories to bum in digestion and are easier to store, thereby are more likely to cause weight gain than carbohydrates containing the same number of calories. In addition to providing energy, fats act as carriers for the fat-soluble vitamins, A, D, E, and K. These vitamins are essential in the promotion of healthy bones, teeth, hair, skin, nails, hormonal functions, such as menstruation, and heart regularity. Fat deposits around the kidneys, heart and liver provide protection and stability to these organs. A layer of fat provides insulation to the body against changes in temperature. This protective and insulating layer of fat is called "white fat." There is another fat deposit called "brown fat" that seems to bum excess calories rather than to store it. This fat is one of the primary sources of heat generation in the body. Those who have more active brown fat tend to be thinner than those who have more dormant brown fat. Brown fat seems to be activated by the presence of essential fatty acids.
Among the various unsaturated fatty acids are three essential fatty acids: linoleic, arachidonic and linolenic, collectively known as Vitamin F and found in oils, fish, some vegetables, nuts and seeds. They are termed "essential" because the body cannot produce them itself They are necessary for normal growth, healthy blood, arteries and nerves. They keep skin and other tissues healthy by preventing dryness and scaliness. Essential fatty acids have been found to help in the transport and breakdown of cholesterol. It has been shown that unsaturated fatty acids help reduce cholesterol synthesis, while saturated fats tend to increase it. Foods that contain cholesterol, such as eggs and shellfish, may affect cholesterol levels less than saturated fats, especially since eggs contain lecithin which metabolizes cholesterol. The recommended daily intake of fats is no more than 30% of overall diet, with only 10% coming from saturated fats.
Proteins are complexes of carbon, hydrogen, oxygen and nitrogen. A protein is a molecule consisting of a long chain of amino acids. The body requires approximately 22 amino acids in a specific pattern to form a protein, although these patterns vary. Most of these amino acids can be converted into one another or manufactured by the body if there is a shortage of one. However, eight of these are essential amino acids because they cannot be synthesized by the body. Foods containing protein may or may not contain all the essential amino acids. Foods that do are called a "complete protein." Most meats and dairy products are complete proteins while vegetables and fruits are incomplete protein foods. To obtain a complete protein meal from incomplete protein foods, one must combine foods, such as a meal of grains and legumes. Beans, peas, grains, nuts, seeds, and some vegetables and fruits all contain some protein.
Next to water, protein is the most plentiful substance in the body. Protein is essential in the development of all body tissues. It is the major source of building materials for muscles, blood, skin, hair, nails, and internal organs, including the heart and the brain. Protein is needed for the formation of hormones, which control a variety of functions such as growth, sexual development, and rate of metabolism. Protein also helps regulate the body's water balance and blood chemistry. Enzymes, which are necessary for various biochemical processes, including the development of antibodies, are formed by protein. Protein is important in the ability to clot blood as well as in the formation of milk during lactation.
Although protein is best used as a "building block" for maintaining body structure and functioning, it can be used less efficiently as a fuel. This happens when there is a dietary deficiency of carbohydrate and lipids or when glycogen reserves have been depleted. The protein burned as fuel produces a byproduct of uric acid which must be excreted by the kidneys to avoid protein toxicity. When sufficient carbohydrates and fats are present in the diet, protein is spared as a source of fuel. Excess protein that is not used for building tissue or energy can be converted by the liver and stored as fat in the body tissues. Deficiencies in protein affect the functions stated above, and can lead to lack of energy and stamina, mental depression, poor resistance to infection, and impaired healing from wounds and disease.
The recommended daily intake of protein varies among individuals depending upon their weight and activity level. This is calculated by multiplying weight by 0.42 grams or more simply by dividing weight by 2. During times of bodily stress, the need for protein increases. There is evidence that protein may be even more satiating than the other macronutrients and so may help decrease hunger and level of consumption.
There are about twenty substances believed to be active as vitamins in human nutrition. Each of these vitamins is present in varying quantities in specific foods and is necessary for proper growth and maintenance of health. With a few exceptions the body cannot synthesize vitamins, but must supply them, typically from fruits and vegetables. Vitamins have no caloric energy value but are important as constituents of enzymes that catalyze most metabolic reactions. There are water soluble vitamins (B-complex, C, and bioflavanoids) which are easily depleted by the body. The equally necessary fat-soluble Vitamins A, D, E, and K are more easily stored in the body.
Minerals are nutrients that exist in the body and in food in organic and inorganic combinations. Approximately 17 minerals are essential in human nutrition. Although only 5% of the body weight is mineral water, minerals are vital to overall mental and physical well-being. Minerals act as catalysts of many biological reactions including muscle response, digestion, metabolism, transmission of nerve impulses, strengthening of skeletal structures, and preserving the vigor of the heart, brain and nervous system. They maintain proper blood chemistry and permit other nutrients to pass into the bloodstream. There are macrominerals such as calcium, chlorine, phosphorous, potassium, magnesium, sodium and sulfur, and microminerals needed in trace amounts such as iron, zinc and iodine. Minerals work in tandem so it is important to maintain the proper balance of minerals in the diet or through the use of supplements. Certain vitamins and minerals known as anti-oxidants may help prevent cancer: beta-carotene, vitamins C and E, selenium, manganese, copper and zinc.
In summary, it is recommended that carbohydrates compose at least 55% of your daily
intake of food, with fats comprising no more than 30% and proteins the remaining 15%. By converting calories to grams (I gram carbohydrate or protein = 4 calories, I gram of fat = 9 calories) you can calculate your daily intake in terms of grams as well as calories. Vitamin and mineral supplements are also recommended (see Appendix A).
In addition to proper nutrition, physical exercise is recommended as an important part of maintaining health. Exercise improves muscle tone, stimulates the processes of digestion, metabolism and elimination, strengthens the respiratory, circulatory and lymphatic systems, and overall promotes mental and physical vigor. Because we live in a highly technological culture, many of us must resort to scheduling some form of physical activity into our more sedentary lives. A good exercise program consists of three dimensions: body conditioning, flexibility, and bone strengthening. Body conditioning involves some kind of aerobic activity such as walking, jogging, or swimming, and helps to activate the heart and lungs and bum fat. A minimal schedule is 3 times a week for at least 30 minutes although some recommend a lighter, daily routine of 20 minutes to maintain a sense of vigor. Flexibility exercises, such as the stretching exercises done in yoga practices, maintain movement in joints, ligaments and muscles, stimulate circulation and alleviate muscle stiffness. These should be practiced every day and may be part of a warm-up or warm-down routine in conjunction with aerobics. Strength building exercises help to maintain muscle bulk and are especially important for women who have less muscle mass than men and are prone to bone deterioration as they age. Such exercises typically involve the use of weights, although one can start out simply by doing resistance exercises found in yoga practices. This should be done at least 3 times a week for 15-20 minutes (see Appendix B).
Because healthful nutrition is essential to proper functioning of the body, any significant changes in eating will correspondingly affect almost all body systems. The list of changes caused by the various eating disorders are numerous and will be outlined simply. Those effects that tend to be of most concern to people struggling with an eating disorder will be discussed in more detail: e.g. changes in metabolism, hunger levels, hydration shifts, weight changes, cognitive changes.
Anorexia nervosa is defined as a restrictive eating pattern resulting in a weight loss of at least 15% below normal. Those who practice such restrictive eating usually have an intense fear of gaining weight and often a distorted body image. They may eat very little all day but if they do eat it is usually foods with strong flavors, such as spicy or sweet foods, in order to try to satisfy whatever hunger they experience. They often exercise vigorously and so are expending more energy than their bodies can obtain from their intake of food. In short, they are malnourished.
Such malnutrition affects their electrolyte balance, gastrointestinal functioning, cardiovascular, renal, pulmonary and endocrine systems, hematology, bones, skin, hair and muscle quality, neurological functioning, and metabolism.
Electrolyte imbalances, such as low potassium or low sodium, can affect heart and kidney functions with the possibility of heart arrhythmias and renal failure. Gastrointestinal functions including impaired digestion and elimination are common and can lead to gastric distress, ulcers and in some cases hepatitis. Weight loss and malnutrition affect the endocrine system which can cause amenorrhea and osteoporosis. Inadequate fat reserves impede estrogen production which impairs menstruation and bone formation. Blood chemistry can be altered leading to anemia or Vitamin K deficiencies which impair blood clotting. Vitamin, electrolyte and endocrine deficiencies can cause muscle weakening, hair deterioration and loss, dry skin or yellowing skin, poor circulation and impaired tolerance to cold. Neurological changes may disrupt the sleep cycle and cause a potential for seizures.
Bulimia nervosa is defined as periodic episodes of binge eating followed by some form of purging behavior either by vomiting, laxatives, diuretics, exercise, or fasting. The quantity of food consumed during a binge varies among individuals and at different times. Sometimes it is not the quantity but the quality of food that determines whether or not people purge, since some foods are regarded by them as "bad" or "off-limits." Some people report eating just enough to be able to purge, since they find that purging acts as a way to relieve stress. Some people who are anorectic will binge and purge occasionally.
Although typically able to maintain a normal weight within 10 lbs., such individuals may nevertheless be malnourished because of poor consumption and assimilation of nutrient rich foods. Similar to anorexia, bulimia affects the following systems: electrolytes, gastrointestinal, pulmonary, cardiovascular, renal, endocrine, hematologic, neurologic, musculocutaneous, bones (including teeth) and metabolism.
Electrolyte imbalances are caused by poor nutrition and by dehydration due to purging. The effects are anemia, dizziness, muscle cramps, cardiac and renal impairments such as arrhythmias and kidney failure. Gastrointestinal disturbances of digestion, assimilation and elimination are common. In addition there can be impairment in the ability to taste (due to vomiting), esophageal tearing, pancreatitis, colon or rectal tearing (due to laxative abuse), parotid swelling (due to vomiting), and impaired liver functioning (due to starvation or ipecac use). Aspiration pneumonia is possible due to aspirating vomit. EKG changes, arrhythmias, and peripheral edema are possible effects to the cardiovascular system. Anemia, menstrual irregularities, muscle weakening, dental disease, and calluses on the hands (from purging) are possible. Epileptic seizures can result from malnutrition and electrolyte imbalances.
Compulsive overeating without purging, now known as Binge Eating Disorder, often results in a body weight at above normal levels. In addition, the types of food consumed when bingeing are often not nutritious. Consequently some individuals may be overweight but undernourished due to the composite of food they actually consume.
Overweight refers to a body weight that exceeds the standard value established for sex, height, and frame. These values tend to undergo revision from time to time due to actuarial tables calculated by insurance companies that assess health risks at various weights (see Appendix C). In contrast, obesity is defined in terms of percentage of body fat that makes up total weight. In general, the recommended range of body fat for men is 10-20% and for women 14-30%. The higher percentage of body fat in women is due to a biological need to have greater reserves of fuel for reproduction.
Being mildly overweight may cause more psychological distress than any serious physical consequences, but it can promote strain on joints, varicose veins, arthritis, and flat feet. There is little evidence of it being life threatening and in some cases it may even be life enhancing, such as in times of food scarcity. It should be noted, that weight is calculated by including bone, muscle, fat tissue and water. Therefore, persons who have high muscle mass but relatively low body fat (e.g. athletes or dancers), may have a higher weight than average, but would not be considered at risk for health problems, so long as they are properly nourished.
Moderate to severe overweight is associated with higher health risks. People who are 20-30% over desirable weight have a 20-30% increased risk of premature death. People whose body weight is 150% of desirable weight have a doubled risk of premature death. Health problems include breathing difficulties, diabetes, gallstones, hypertension and heart disease. Obese people are more prone to certain forms of cancer: colorectal (men and women), breast, uterine, or ovarian cancer (women), prostate cancer (men).Because body fat is difficult to calculate without special equipment, the Body Mass Index (BMI) can be used as an alternative measure of proper weight for height. BMI = weight(lbs.) x 700/ht(in.)'. The recommended range is 18-25. Below 18 may be a sign of malnutrition. Between 25 and 30 is considered a health risk. Above 30 is considered obese and damaging to health. Another variable associated with health risks is the distribution of fat in the body or "body shape." Affectionately referred to as "apples" or "pears," those with distributions of fat around their middles (apples) seem to be at greater risk for diabetes and heart disease than those with greater distributions of fat around their hips, bottom and thighs (pears). To calculate your body shape measure your waist-to-hip ratio. Measure your waist at your navel (in a relaxed state) and your buttocks and hips at their widest point. Divide the first by the second. Preferred values are less than 0.8 for women and less than 1.0 for men. It is possible to attain the preferred range by adopting a healthful eating plan and a program of moderate exercise.
Our weight is influenced by a set of genetic factors in addition to nutrition and exercise. Genetic factors determine the bone density, frame, and metabolism rate with which we are born. We also are born with a certain number of fat-cells that influence the ability of our body to store fat. These fat-cells seem to be relatively stable in number over the course of our lifetime, although there can be some increase in the number of these cells during adolescence or due to dietary changes. The fat-cells are the main storage area in adipose tissue of energy reserves. Fat-cells affect body weight by virtue of their size, which can increase or decrease depending upon diet and activity level.
These various genetic factors have led to the theory of set-point, which suggests that our bodies are physiologically programmed to maintain a specific weight range over our lifetime. Set-point is believed to account for the rather consistent weights that people seem to maintain without effort or that they return to following a diet. It is considered to be the body's genetically desirable weight range and may be a preferred way of assessing a person's ideal weight. Although some people do maintain a weight above or below their set-point threshold, this seems to be done with considerable strain on the body. Those who are under their set-point tend to regain any weight lost by dieting more easily than those who remain within their set-point range.
There are several factors that seem to alter set-point upwards or downwards. Certain drugs, such as amphetamine and nicotine, may lower set-point, but only so long as the drugs are used. Since these drugs cause serious health consequences, they are not recommended as a form of weight control. Certain psychotropic medications, including some anti-depressants, may raise the lower set-point threshold.
Dietary changes can affect set-point. It appears, however, that the lower set-point is more resistant to change by diet than the upper set-point. This may be a survival mechanism to defend the body against starvation by resisting further weight loss. Dietary practices that do lower a person's weight beyond their lower set-point threshold will not alter their setpoint, but will stimulate a dramatic increase in preoccupation with food, weight and hunger.
The upper set-point threshold seems less well defended and can be raised by diets high in simple sugars, refined carbohydrates (e.g. white flour), and fats. Chronic overeating and maintaining a weight above the upper set-point threshold for a long period of time may also promote an increase in the upper threshold. In addition, chronic and repetitive dieting may contribute to a higher set-point threshold. This appears to be a survival mechanism in response to the periods of inconsistent and insufficient food supply during dieting, so that the body increases fat storage during more plentiful times.
Regular aerobic exercise seems to promote weight loss by burning
calories and stored fat, and by lowering the set-point weight.
Therefore, it is exercise and not diet that seems capable of lowering
set-point. Maintenance of the exercise program is necessary to sustain
the lowered threshold. Moderate exercise results in decreased body
weight and food consumption. Vigorous exercise, however, may cause
various physiological problems, including lowered metabolism. Other
complications found among those who "overtrain" include increased
appetite, stress on joints and ligaments, cardiovascular risks,
hormonal changes which can cause amenorrhea, chronic fatigue, insomnia,
increased emotional tension and decreased libido. In short, while
moderate exercise is recommended for overall good health, excessive
exercise can be damaging to your health.
There is some evidence that set-point range shifts upward as we grow older, especially if a person maintains a high-fat diet. The fat to muscle ratio increases with age. Since fat requires fewer calories to maintain than muscle, a higher fat ratio will mean a lower metabolism. A regular program of exercise can help to offset these effects. Those who gain only modest amounts of weight as they age, however, tend to have better survival rates than those who do not. Underweight older women tend to be more prone to osteoporosis, heart trouble, bone fractures, and menopausal complaints than older normal weight or modestly overweight women. Skin elasticity diminishes with age so those who are underweight are prone to more wrinkles and muscular diminishment. Likewise, with age, it is difficult to tone up skin that has stretched due to being overweight.
Set-point theory suggests that what is the most healthful weight for one's height should guide one's weight goals. Efforts to maintain weights well below one's lower setpoint threshold will result in psychological and physiological strain with little chance of long term success. Likewise, the ability of the body weight to "drift upward" should caution a person against engaging in chronic overeating or repetitive dieting practices. Instead, proper nutrition and moderate exercise seem to be "the rule of thumb" for maintaining a healthful weight for one's body.
Hunger is the result of several psychological and physiological factors. The use of particular foods to satisfy emotional needs is a common coping strategy for many people, especially given the abundance, variety and accessibility of food in our culture. Normal physiology as well as the biological changes caused by disordered eating can also promote it cravings" for particular nutrient groups and influence our response to these cravings. Nutritional deficiencies, resulting from undernourishment, can provoke specific cravings for carbohydrates, proteins or lipids.
Satiety is defined as the ability of a food group to inhibit further eating after the termination of a meal. Satiation is the ability of a food to terminate a meal that is in progress. Carbohydrates seem to have a potent effect on both satiety and satiation. Carbohydrates tend to increase serotonin production which can induce sleep and diminish pain. Some people, therefore, crave carbohydrates for these physiological and psychological effects. Fats or lipids have a lower satiation value than carbohydrates but a good satiety value. Protein may have the highest satiety value of all three macronutrients. Therefore, one might consume more fats or proteins than carbohydrates at a sitting, but not have much hunger afterwards for further eating.
Those who reach a suboptimal set-point threshold will experience an increase in their preoccupation with food, hunger and weight In the initial phases of starvation, hunger will be a driving force and promote an increased preoccupation with food, a loss of sexual desire, greater irritability, depression, and increased self-preoccupation. Over time a person will become more inactive, apathetic, and tend to withdraw from activities.
Unlike ordinary people who are starving, those who are anorectic will deliberately try
to override this hunger drive by distracting themselves with activity or sleep. This is because they are determined not to respond to the hunger. If they do eat, it is usually a low-calorie, strongly flavored food, such as sweets and spices, that can quickly their diminish hunger. Intense exercise, which releases endorphins, can also be used to dampen appetite. Even though they experience a loss of appetite, these individuals nevertheless can still be preoccupied with food which they will deliberately resist.
Those who binge and purge disrupt their normal experience of and response to hunger. Often a binge is preceded by a period of restrictive eating which promotes strong hunger. Feelings of hunger are usually responded to with fear and restraint to avoid bingeing. The mounting hunger eventually cannot be resisted and leads to binge eating. If the binge is followed by purging, the person returns to a state of extreme hunger once again. This perpetuates the cycle of bingeing and purging and promotes a continuous preoccupation with food. Like the anorectic individual, the bulimic individual is usually malnourished.
There may be biological adaptations to the abnormal eating patterns of bulimia nervosa. Because the foods eaten during a binge tend to be high in sugar, it is mainly sugar that is absorbed before purging. The body adapts to living on a high sugar diet by producing large amounts of insulin just after eating begins. This increases appetite and promotes fat storage. Attempts to stop eating after consuming a relatively small amount usually fail due to the voracious appetite caused by this insulin-produced hypoglycemic state, thus making a binge almost inevitable.
When a person binges and purges by vomiting, the body consistently receives misinformation about the nutritional value of a quantity of food, since a large quantity may be eaten but only a small amount of nutrition will be absorbed. Sugars are absorbed more quickly than fats and protein, so the latter two are likely to be what gets purged. Since protein and fats have greater satiety than sugars, large amounts of sugary foods will likely be consumed in order to achieve satiety.
Those who tend to binge but not purge are likely to be responding to emotional cues to eat rather than physical cues. Like those who are bulimic, they have an impaired ability to identify and respond to physical hunger and satiety cues. Therefore, they are likely to be malnourished, even though they may be consuming adequate calories for their energy expenditure. They are also likely to store more fat since their consumption level is guided more by a psychological response to eating rather than a physical response. Similar to those who are bulimic, those who binge on sugary foods will likely promote impaired insulin functioning which affects appetite and fat storage.Taste and thereby appetite for certain foods can be affected by several factors. Foods eaten in the morning tend to taste different than if eaten later in the day, due to the tongue's exposure to saliva and air during sleep. "Taste adaptation" can occur if taste buds are exposed to a single taste over a period of time, e.g. only sweet or salty foods. This diminishes appetite for that taste. If different tastes are eaten at a sitting there tends to be greater appetite than if only one type of taste is eaten at a sitting. Purging can impair taste bud sensitivity and thereby can promote preferences for more strongly flavored foods. Studies also suggest that being underweight can cause an "extended taste responsiveness" to sugar. This is defined as an increased tolerance to sweet foods which promotes its consumption. When stable-weight people consume a certain amount of sweet food, they tend
One-half to four-fifths of the body weight is comprised of water. The exact amount depends upon the amount of body fat with greater body fat yielding less water. There appears to be a genetically determined range of total fluid volume for each person, which the body tries to regulate. Hydration shifts are a change in the total volume of body fluids and thereby affect body weight. Following a change in body fluid, the body will try to restore fluids to its normal range within minutes or within 48 hours. These weight changes are not due to changes in muscle mass or fat deposits. The normal daily turnover of water is due to ingestion of food and drink, oxidation, excretion, and sweating, comprising 4% of total body weight in adults. High temperatures, high altitude, dry air, exertion, and diarrhea can increase the rate of loss.
When people with eating disorders abuse laxatives, diuretics, or vomit on a regular basis, their bodies become dehydrated. The body responds by trying to retain fluid and will do so until the body experiences a consistent availability of fluids. This is called rebound edema. Those who experience this edema may also experience tremendous thirst, decreased urinary output, puffiness in the fingers, ankles or face, cracked skin, dizziness, and tingling in the extremities. This rebound edema can last up to two months following rehydration.
Underfeeding can increase the relative level of water volume to body tissue, thus promoting bloatedness. Protein deficiencies, common among those with eating disorders, also produces edema. Alcohol consumption and high sodium intake can contribute to puffiness. Fluid retention is the body's way of trying to avoid the more serious consequences of dehydration that can cause circulation problems, kidney damage and eventually death.
Food that is consumed can be used immediately as a source of energy or can be converted into storage forms for later use. There are three main stores of metabolic fuels: tricylglycerols in adipose tissue, ketones (fatty acid compounds) in the liver, glycogen as a carbohydrate reserve in the liver and muscle. There is also an increase in the synthesis of tissue proteins after eating a meal, which can be used as a metabolic fuel in the fasting state.
In the fasting state, the time between meals, these reserves are mobilized. Glycogen is a source of glucose. Adipose tissue provides both fatty acids and glycerol from tricylglycerol. Some of the protein reserves can also be mobilized, if necessary. Muscle and tissue can use fatty acids, ketones and muscle glycogen reserves as fuel. The nervous system, however, requires a steady supply of glucose. This is to maintain a proper blood concentration of glucose in order to avoid hypoglycemic coma.
Ordinarily there is sufficient plasma glucose supplied by liver glycogen to provide adequate glucose for the brain. The release of free fatty acids from adipose tissue and ketones from the liver help to nourish muscle. However, there is only a relatively small amount of glycogen in the liver. The total pool of glycogen in both liver and muscle can exhausted within 24 hours of fasting. If this does occur, glucose can be synthesized from the breakdown of protein or glycerol from tricylglycerols. Fatty acids, however, cannot supply glucose.
When carbohydrate is absent from the diet, protein will be converted to carbohydrate to maintain blood sugar at the proper levels. If neither protein nor carbohydrate is available from the diet, the body will begin to break down protein-based structures to convert them into amino acids and glucose. This can result in serious damage to muscles and organs, including the heart. Not only does the conversion of amino acid to glucose use up as much energy as it will eventually supply, but the nitrogen released can be toxic. The continuing requirement for glucose synthesis from amino acids in fasting and starvation explains why there is often a considerable loss of muscle when people fast, even if they have apparently adequate supplies of adipose tissue reserves. In people with little adipose reserves, typical of anorectics, there will be even more loss of muscle from starvation.
Glycerol from triglycerides can be used to produce blood sugar, but without adequate carbohydrate in the diet, this will produce a byproduct called ketone bodies. This is because adequate supplies of carbohydrate are necessary for the proper metabolism of fats. The production of ketones, called ketosis, causes symptoms of fatigue and dehydration and over time more seriously in renal and hematological problems eventuating in coma.
Ordinarily any excess blood sugar is not stored as fat, but is burned or stored as glycogen, a sugar water complex. The bodies of lean people convert blood sugar to fat only when their glycogen stores are saturated. Those who restrict their calories (i.e. diet) and then resume eating normally, however, can impair their ability to manage their blood sugar levels. This is due to the development of insulin resistance and an increase in the enzyme lipoprotein lipase which moves fat into the fat cells.
Eating will normally produce an insulin rush which limits our appetite. Insulin, supplied by the pancreas, also acts to remove any excess glucose from the blood to be used by the cells for energy or to be converted to fat for storage. Insulin resistance interferes with this appetite reduction mechanism and with the transport of glucose into the cells. It can inhibit the release of glucagon, the hormone that signals us when our stomachs are full, thus keeping appetite high. Glucagon helps regulate sugar by releasing stored sugar into blood. If it is sluggish it can affect blood sugar regulation.
If insulin is slow to appear after eating a meal heavy in sweets, glucose cannot move from the blood into the cells and blood sugar will soar. Finally, when insulin secretion does come, it comes in full force, forcing glucose out of the blood quickly and leading to a blood sugar drop. This causes weakness and shakiness. If the blood sugar drops too low, the nervous system is in danger. The brain relies on blood sugar and cannot be deprived of it. This is what happens when a diabetic gets an overdoes of insulin so that all the sugar enters the cells and none is available for the brain, causing a coma. High levels of insulin in conjunction with low blood sugar also tend to make fats and sweets more desirable by suppressing serotonin, the neurotransmitter that decreases carbohydrate cravings. Therefore, appetite will remain high, especially for sweets and fats, which will be converted to the fat cells for storage. The consumption of complex carbohydrates, B-complex and chromium can help regulate insulin.
Those with hypoglycemia may experience a less drastic drop in blood sugar but may have some similar problems. Their decrease in blood sugar is usually responded to by a secretion of adrenaline since the body experiences itself in danger. This helps mobilize stored glucose from the liver but puts the whole body on alert. This leads to a feeling of apprehensiveness, tremulousness, rapid heart beat, rapid shallow breathing, and cold clammy hands. This reaction may not always be severe but depends upon how low the blood sugar drops and how drastically the adrenals respond. Such drops in blood sugar can constitute a state of internal stress which can aggravate emotions, and promote irritability, nervousness, exhaustion, headache, and even ulcers (see Appendix A: Glycemic Index).
Such hypoglycemic attacks can also be due to poor liver functioning which affects the release of glucose into the cells. Overeating overworks the liver. If the liver is not functioning properly many of the toxic materials it filters will remain in the blood and will be circulated throughout the body. This can cause an overall heaviness, achiness, and soreness as well as malnutrition. It can also affect the nervous system leading to feelings of apathy, lethargy and depression. Blood sugar can be controlled by the use of complex carbohydrates, which are digested slowly, a well functioning liver and proper insulin regulation.
Certain personality traits may also affect digestive functioning. Those who ignore hunger or suppress emotional needs may trigger increased gastric activity which eats away at the stomach lining. This often leads to overeating or snacking to keep the stomach full. When the extra foods are sweets, they can trigger a further secretion of acid as well as the blood sugar problems above. Feelings of hopelessness, depression and inadequacy may decrease secretion of stomach acid. This weakens protein digestion and drops the protective barrier- against bacterial overgrowth in the small intestine. This promotes indigestion and overloads the liver. This suggests there is a dynamic interplay between mind and body.
When a person is undernourished, the body will respond by reducing the metabolic rate and becoming more efficient in its use of the calories that are available. The effect of this will be to stabilize weight. As metabolic rate decreases, the work output of the heart decreases, muscle tone declines, body temperature decreases, blood sugar levels decline and all chemical reactions in the body decline. This occurs in obese or normal weight people, who restrict their food intake to less than 1200 calories for two weeks or longer, maintain a weight below their set-point, or lose at least 10% of body weight. If a person overeats or maintains a weight above set-point, the body will initially become less efficient in the utilization of calories in order to try to resist weight gain.
One study found that metabolic rate progressively decreases with dieting, an average of 0.9% per day with a total decrease of 12-17% after 2 weeks. Regardless of how rapid the decline, the minimum metabolic rate seems to be no less than 70% of normal. Those who consume 1500 calories above their normal daily intake experience a 12-29% increase in metabolic rate after 2 weeks. However, weight gain will occur with continued overeating.
The metabolism of bulimics seem to vary depending upon the severity of purging. The more severe the bulimia, the lower the RMR, which is due to being in a semi-starvation state similar to anorectics. In addition, anti-depressants, commonly used in the treatment of bulimia, can reduce metabolic rate by as much as 24%. There is evidence to suggest that the neurotransmitter norepinephrine (NE) is reduced in the active phases of both Anorexia and Bulimia. Decreased NE activity can result in reduced energy expenditure and thereby promote weight gain.
Dieting cycles or "yo-yo dieting" have serious effects on metabolism. It is associated with increases in blood pressure, insulin resistance, and a tendency to lose less weight with repeated cycles. Also the rate of weight regained following dieting tends to increase with each cycle. This seems to be due to an increased efficiency in the use of calories and an increased fat formation ability as a survival mechanism. Because of increased fat formation ability, the new tissue from the weight regained has a higher percentage of metabolically inactive fat than the tissue lost. Fat free mass or lean body tissue (muscle) is the primary determinant of resting metabolic rate (RMR). RMR decreases with weight loss because of the loss of this metabolically active muscle. Those who lose weight by exercise and diet, however, do not experience a significant decline in RMR, since they are maintaining more muscle mass. Dieting can increase appetite for fats and carbohydrates, which have a lower thermic -output than protein, and thereby promote weight gain. Consequently, unless medically indicated, dieting is not recommended for weight loss of weight control. Rather, following a plan of moderate eating and exercise that is sustained over one's lifetime is the recommended means to health and vigor.
Most complications that arise from eating disorders are reversible with the restoration of proper nutrition. In cases where the extent and duration of the eating disorder is severe, there may be irreversible damage to growth, reproductive systems and bone density. In most cases, however, proper nutrition and exercise will in time restore normal functioning of all biological systems.
Those who begin to eat in a more nutritionally balanced fashion, neither undereating nor overeating, and who maintain a relatively consistent activity level will begin to restore their body to its normal set-point range. The sign that this has been accomplished is when there is less preoccupation with food, hunger and weight, and when there is restoration of normal menstrual functioning. It usually takes 6 months to a year for a pattern of consistent eating and exercise to restore the body to its normal functioning.
Changes in any part of a person's food intake pattern will affect a person's hunger pattern. For example, if a person begins to eat breakfast after not having eaten breakfast for several years, the body will adapt to this change by developing a hunger peak at this time. That is because the body is being retrained to expect food at different times than it had before. Therefore, a person may experience hunger at different times than before. This can be frightening and may be regarded as a sign of "losing control." Instead, it should be regarded as the body's normal response to a new schedule of eating, which retrains the body to expect food at different intervals than before.
Those who are accustomed to restricting or resisting eating are likely to become frightened by any response to hunger they engage in. Some will not be able to properly identify what is hunger, as they have trained themselves for a long time to ignore these signals. Those who have tended to eat in response to emotional states and not physical cues, are likely to find it difficult to identify what is actual hunger. Some who may have eaten most of their- food at night may not ever have experienced hunger upon awakening. They may be frightened by the introduction of these feelings when they begin to diminish their evening eating. All will go through a process of relearning how to identify and respond to hunger which takes some time to normalize. In some cases, it can take up to a year for the body to normalize physiologically and at least at long for a person to adjust psychologically to changes in eating habits.
The most famous study of the physical and psychological effects of starvation and recovery was done by Ansel Keys after World War H. Volunteer subjects restricted their food intake to the point of starvation for 3 months. Their metabolism declined and their preoccupation with food increased. They became increasingly irritable, angry, depressed, anxious and had a lowered sex-drive. When they began to eat normally again they continued to experience these emotional difficulties for some time. They continued to be preoccupied with body shape and food for some time after resuming normal eating. Similar to many anorectic people, they did not gain weight until they ate a significant number of calories, and most did not feel satisfied unless they ate a significant number of calories at a sitting. Therefore, those who have been anorectic are likely to experience intense feelings of hunger, a tendency to eat larger quantities of food than previously and to require a period of time to readjust their body image and eating habits.
Those who are accustomed to resisting their hunger may regard their responses to hunger cues as a "defeat" and want to restrict their eating once again. Those who are accustomed to purging after eating may not be physically comfortable with the feelings of fullness after eating as their body relearns digestion and assimilation. This bloated feeling often stimulates the desire to purge, if only to relieve the pain. It is important for these people not to restrict or purge, since it only resumes the cycle. Rather, they should adjust their eating patterns to offset the discomfort. This can be done by eating smaller, more frequent meals that are more easily digestible and which helps normalize metabolism. The soluble fiber in fruits and vegetables tends to promote bloating and should be limited for awhile until normal processes are restored. Cooked carbohydrates and soups may be easier to digest initially. The person can experiment with what foods are most physically agreeable at different stages.
The normal response to hunger includes: a food intake pattern that is specific or regular with a modest degree of flexibility, a sufficient caloric consumption to maintain weight within set-point range, calories that are consumed during regularly scheduled 4 to 6 daily intake periods, within 4 to 6 hour intervals, a response to hunger peaks when they are in the minimal to modest range, adequate intake of protein, carbohydrate and lipids, and fewer lhte evening peaks of food consumption.
When a person maintains a weight within steeping range, the body seems to be more tolerant of variations in intake than when it is beyond the range. Therefore, those who restore and maintain a normal weight for their body, will find themselves more able to tolerate occasional periods of excessive or diminished eating. Maintaining a regular intake ot' at least 1200 calories for women and 1400 calories for men will help the body restore normal hunger and metabolic range (see Appendix D).
Normally there is a cycle of hydration levels throughout the day and over time. This is due to changes in hormonal levels, environmental effects and activity level. Illness can also decrease fluid levels. Being aware that hydration levels shift normally as well as in the process of recovery, can help a person cope with what appears to be increases in weight due to consumption. This weight gain is due to water and not due to increases in stored fat. Continuation of normal nutritional eating will help the body adjust its fluid, reduce bloating and will restore the body to its optimal weight.
Those who frequently hinged and purged may experience a 2 to 5 lb. weight gain within the first three days following abrupt cessation of the behavior, due to rehydration. Increased carbohydrate consumption will also result in a weight increase, even it' the diet is low calorie. This is due to increases in urinary salt and water levels, which results in edema. Consumption of fats, instead of carbohydrates does not result in salt retention. Protein consumption provokes a delayed retention of salt.
Those who maintain a normal eating pattern will restore normal fluid levels, usually within two months of restoration. There are several ways a person can restore proper fluid balance to the body. The first is to drink sufficient fluids throughout the day until the body adjusts to the non-deprivation state. The recommended intake is 8 cups per day until frequent urination occurs, a sign of fluid restoration. Increasing caloric intake, increasing protein intake, decreasing alcohol and salt consumption, or decreasing binge/purge episodes will each begin to restore hydration levels to their proper point.
There are numerous changes in metabolism rate due to erratic or restrictive eating patterns. Those who are anorectic or who binge and purge frequently are likely to have lowered metabolisms. Those who have dieted repeatedly, even though they may now be eating more, are likely to have lowered metabolisms. Those who are overweight, but have not dieted repeatedly, may have a somewhat higher metabolic rate due to maintaining a weight that is above their steeping range.
People with anorexia or bulimia will not experience a normalization of metabolic rate until their weight is within steeping range regardless of increased caloric consumption. Those who have a higher metabolism will need to normalize their food intake and increase their level of exercise to establish a more optimal metabolism level.
During initial refeeding weight gain among anorectics seems to be inconsistent. Some people report gaining weight much more slowly than would be expected given the increased calorie consumption and lowered metabolism. This seems to be due to a hydration shift in which edema is lost and thus weight drops. Another explanation for slow weight gain is that increased energy output has occurred in response to the loss of body fat that would have provided ' insulation against temperature changes. With lack of body fat, the body produces more heat in order to stay warm. This is called adaptive thermogenesis. This increased heat production bums more energy and therefore will increase metabolism until fat reserves are restored to provide adequate insulation.
During initial reseeding those who are bulimic will likely experience an increase in weight. This is due to a lowered metabolic rate and decrease in purging activity which may have controlled weight. The use of anti-depressants as a treatment for bulimics can reduce metabolic rate, thus leading to a weight gain upon refeeding. Norepinephrine activity, a neurotransmitter, is reduced in the active phases of Anorexia and Bulimia and reduces thermogenesis and energy expenditure. Upon refeeding, this reduced energy expenditure may cause a weight increase which will be restored to proper levels after a period of normal eating.
People who are normal weight and bulimic may experience an initial weight gain following increased intake, which moderates as the body adjusts to a consistent pattern of increased caloric intake. Once the rate of intake has stabilized and the binge/purge behavior has stopped, people can actually lose weight if the binge/purge cycling led them to maintaining a weight higher than their steeping range.
In summary, return of normal metabolic rate entails the maintenance of a consistent eating pattern of minimally 1200 calories for women or 1400 for men, including adequate supplies of all the major nutrient groups, accompanied by moderate exercise. Consistency is important. Returning to restrictive eating, purging or overeating will once again interfere with the body's ability to restore balance in the metabolism.
The host of physiological effects of eating on the body can seem daunting to understand and master. Fortunately, most of these processes are controlled by the body without our conscious effort so long as we provide it with a nutritionally sound program of eating and exercise. Since we live in a culture that is abundant in readily available, inexpensive sources of nutrition it should not be difficult to provide the body with what it needs. It is also possible to provide a moderate amount of exercise despite our otherwise hectic schedules. The results of such a plan of eating and activity are increased health and vigor, which can be felt within a relatively short period of time.
Given that these recommendations are not especially difficult to follow, we must then address the most important obstacle that interferes with such a regime, i.e. the mind. Clearly, it is psychological obstacles that pose the greatest interference to following these recommendations. It is not possible in the present discussion to pursue these factors in detail, but some remarks may be offered.
It is the mind that initiates an eating disorder and it is the mind that will ultimately resolve it. Even if one is overweight as a child, it is one's own reactions or that of others that will determine any concern over one's bodily state. Even if a medical condition requires us to adjust our eating patterns, it is usually psychology and not physiology that interferes with our willingness to follow such a recommendation.
What is required in following sound nutritional practices or exercise is not physically difficult. It is far easier to tolerate than what is physically endured by those who restrict their eating, binge until they feel pain, or who strain their bodies by purging or excessive exercise. Clearly, it is not physical pain that such people are trying to avoid. It is psychological pain. The pain of "giving in to" their need to eat, the pain of "losing control," the pain of "rejection" by others because of how they may appear, the pain of not being "perfect," the pain of foregoing the "solace" that food often offers. All these psychological "pains" are far more difficult to endure for many people than any physical hardship. Unless this psychological distress is addressed, it will be difficult for most to consistently follow what is physically advisable.
The above information is provided to try to put into perspective what our bodies naturally need from us and what can reasonably be expected of them by us. Any serious effort to restore a natural balance to our eating must include awareness of these natural processes. This awareness, however, must be accompanied by a growing sense of what psychological factors are at play that override our abiding with what is biologically sound for our bodies. This entails a process of self-exploration and self-understanding that promotes the development of more healthful, more effective methods to resolve the concerns or aspirations we may be addressing through our eating. Once this is achieved, the mind and body will be in a more balanced relation. This can free up our physical and psychic energy to be used in more deeply satisfying ways.
Rudolph Ballentine - Diet and Nutrition
David Bender - Introduction to Nutrition and Metabolism
Christopher Fairbum - Binge Eating
Christopher Fairbum - Overcoming Binge Eating
Ann Louise Gittleman - Beyond Pritikin
Deborah Hutton - Vogue Beauty for Life
Allan Kaplan - Medical Issues and the Eating Disorders
John Kirschman - Nutrition Almanac
Phillip Lipetz - The Good Calorie Diet
Dan Reiff & Kathleen Reiff - Eating Disorders: Nutrition Therapy in the Recovery Process
Judith Rodin - Body Traps
Labuza Sloan - Contemporary Nutrition Controversies
Katherine Zerbe - The Body Betrayed
1. Eat a variety of foods including plenty of grain products, vegetables and fruits.
2. Choose a diet low in fat, saturated fat, and cholesterol.
3. Choose a diet moderate in sugar, salt, sodium and alcohol.
4. Balance the food you eat with physical activity including aerobic exercise, flexibility exercise and strength training exercise.
VEGETABLE SERVINGS: 3-4
FRUIT SERVINGS: 2-3
MILK GROUP SERVINGS: 2-3
MEAT GROUP SERVINGS (CAN INCLUDE VEGETABLE SOURCE OF PROTEIN): 5-6
BREAD, CEREALS, RICE, PASTA SERVINGS: 6-11
30% LIPIDS (maximum) (NO MORE THAN 10% FROM SATURATED FATS)
1 GRAM CARBOHYDRATE = 4 CALORIES
1 GRAM PROTEIN = 4 CALORIES
1 GRAM LIPIDS = 9 CALORIES
New Total is calories needed for zero activity. Multiply x 1.4 for moderate activity.
Puffed Rice Cereal
Glucose Potato Chips
White Bread Yams
Whole Wheat Bread
Grape Nuts Dried Peas
Potatoes (Russet) Regular Oatmeal
Parsnips Orange Juice
Whole Grain Rye Bread
Quick Rolled Oats
White Rice 30-39%
Brown Rice Apples
Bananas Breaded Fish Sticks
Corn Tomato Soup
White Potatoes Chickpeas
Milk (Whole or Skim)
White Pasta Grapefruit
Whole Wheat Pasta Plums
Pinto Beans Cherries
*Eat foods lower on index (less than 70) to regulate blood sugar or combine higher index foods with lower index foods
or protein (e.g. brown rice and chicken).
BALLROOM DANCING 330
BED MAKING 234
BICYCLING (6MPH) 240
BICYCLING (12MPH) 410
X-C SKIING 700
DESK WORK 132
DRIVING A CAR 168
FARM WORK IN FIELD 438
HORSEBACK RIDING 480
IRONING (STANDING) 252
JOGGING (5MPH) 740
JOGGING (7MPH) 920
JUMPING ROPE 650
LAWN MOWING (HAND) 462
PAINTING AT EASEL 120
PIANO PLAYING 150
RUNNING IN PLACE 650
PREPARING A MEAL 198
SCRUBBING FLOORS 216
SITTING AND EATING 84
SITTING AND KNITTING 90
SITTING AND READING 72
SLEEPING (BMR) 60
STANDING UP 128
SWIMMING (SLOWLY) 300
WALKING (3 MPH) 320
WALKING DOWNSTAIRS 312
The calories spent in each activity vary in proportion to body weight. For example, a 100 pound person would decrease these numbers by 1/3. A 200 pound person would increase these numbers by 1/3.
SIMPLE CALCULATION FOR IDEAL BODY WEIGHT:
(WOMEN) 100 POUNDS FOR FIRST FIVE FEET + 5 POUNDS/INCH ABOVE
5 FEET + OR - 10% based on frame
(MEN) 106 POUNDS FOR FIRST FIVE FEET + 6 POUNDS/INCH ABOVE 5 FEET + OR - 10%
WEIGHTS DO NOT INCLUDE CLOTHING
BMR = IDEAL WEIGHT X 10
MULTIPLY RESULT X.30 (.40 FOR ACTIVE PEOPLE)
ADD BMR NUMBER AND ACTIVITY NUMBER TOGETHER
Last Updated: 4/29/10