Diets and weight management
Diets are regulated selections of foods, specially designed and prescribed for medical and/or general nutritional reasons.
Eating the proper diet is critical for the health of individuals, groups withspecial medical and dietary needs, and entire populations afflicted with malnutrition.
The Food and Nutrition Board of the National Research Council of the NationalAcademy of Sciences has determined dietary standards called Recommended Dietary Allowances (RDA). These standards explain the daily amounts of energy, protein, minerals, and fat-soluble and water-soluble vitamins needed by healthymales and females, from infancy to old age.
Experts in nutrition recommend a variety of foods and the maintenance of an ideal weight. Large amounts of fat, saturated fat, and cholesterol should be avoided. Individuals should consume adequate starch and fiber and avoid excesssugar and sodium.
The U.S. Department of Agriculture and the U.S. Department of Health and Human Services have developed official dietary guidelines that include these seven basic recommendations:
- Eat a variety of foods.
- Control yourweight.
- Eat a low-fat, low-cholesterol diet.
- Eat plenty of vegetables, fruits, and grains.
- Eat sugar in moderation.
- Use salt in moderation.
- If you drink alcohol, do so in moderation.
The food pyramid, developed by nutritionists, provides a visual guide to healthy eating. At its base are, those foods that should be eaten numerous timeseach day, while at its apex are those foods that should be used sparingly. The pyramid suggests a range of servings in each group so that the number of servings can be adjusted to suit each individual's caloric requirements. The daily recommendations (from bottom to top) of the food pyramid include:
- Bread, cereal, rice, and pasta: 6-11 servings
- Vegetables: 3-5 servings
- Fruits: 2-4 servings
- Milk, yogurt, and cheese: 2-3 servings
- Meat, poultry, fish, dried beans, eggs, and nuts: 2-3 servings
- Fats, oils, and sweets: use sparingly.
Diets promote a balanced selection of foods vital for good health. By combining foods appropriate for each individual, having good eating habits, and drinking the proper amount of water, one can maintain the best possible health. Having good eating habits typically means eating three meals a day, and snacksto satisfy hunger. It is regulated mostly by internal signals of hunger, appetite, and satiety--we eat when hungry and stop when satisfied. Good eating promotes health and well being. A variety of food choices provides a balancednutrition. As opposed to this, dysfunctional eating patterns such as fasting,bingeing, dieting, skipping meals, usually means eating more or less than what the body's requirements are. The person often feels fatigues, irritable, and is less able to concentrate. Health problems may develop due to loss of essential nutrients from the body. The risk of developing eating disorders is increased.
In order to inculcate good eating habits in children, it is important for parents to offer a variety of nutritious foods at regular intervals. There should be planned meals and snacks. The child should be helped to identify hungerand fullness, and most important of all, the parents should be a good exampleof normal healthy eating and lifestyle.
Sometimes, metabolic disturbances in the body can cause health problems. Theindividuals may have food intolerances, serious food allergies, or other complications such as diabetes, heart disease, salt-induced hypertension, and soon. In such a case changes to the normal diet become essential and the physicians may prescribe a modified diet. Since these diets are intended to treat disorders, most of the diets need to be maintained permanently. Therefore, thephysicians ensure that the body gets all the essential nutrients that are needed in moderation. Adopting a healthy, active life-style is also advised.
Carbohydrates, proteins, and fats provide energy in the form of calories to fuel body functions. An older adult or sedentary woman needs about 1,600 calories daily, while children, teenage girls, active women, and sedentary men need about 2,200 calories daily. Active men, teenage boys, and very active womenneed about 2,800 calories daily. When an individual consumes as many calories each day as his body uses, he is in a state of energy balance and neither gains nor loses weight. When more calories are eaten than the body uses, the excess calories are stored as fat and weight increases. On the other hand, when fewer calories are consumed than the body needs, stored fat is burned and weight decreases.
Low-calorie diets are designed for weight reduction and are prescribed for people who are overweight or obese. High-calorie diets are recommended for people with greatly increased energy needs such as athletes in training or individuals fighting diseases such as cancer, AIDS, or cystic fibrosis. High-calorie diets are also prescribed to treat anorexia nervosa.
Calorie-modified diets are planned by dieticians and prescribed following a complete physical examination and dietary history. A low-calorie diet providesenough energy (usually 1,000-1,800 calories) to meet the person's metabolicneeds and activity level. It includes a balanced variety of foods, but limitscarbohydrates and alcohol. A low-calorie diet aims to promote a weight lossof 1-2 lb per week. A high-calorie diet usually provides an extra 500-1,000 calories, leading to a weight gain of about 1 lb per week for most people. Ithas a high protein content, normal fat content, and emphasizes foods that pack many calories into a small volume. Snacking between meals is encouraged asa way to increase the calories consumed.
Fiber has important nutritional benefits such as facilitating the movement offood through the digestive tract, helping to prevent constipation.
Recent evidence suggests low dietary fiber may be responsible for increasingthe incidence of diverticulosis and may be associated with cancer of the colon.
Fruits and vegetables are excellent sources of fiber. High-fiber diets, including whole grains (especially bran), raw vegetables, unpeeled fresh fruits, nuts, and seeds, are recommended to:
- Increase fecal bulk
- Increase intestinal movement
- Prevent or treat constipation,
- Crohn's disease, or
- Irritable bowel syndrome
- Help lower cholesterol
- Assist with weight loss in people who are overweight and
- Improve sugar tolerance in diabetics.
Low-fiber diets exclude raw fruits and vegetables, whole grains, nuts, and seeds, while emphasizing soft, mild foods. They are recommended to:
- Decrease fecal bulk
- Slow intestinal movement
- Decrease stomach acid secretion
- Treat a variety of disorders including indigestion, diarrhea, bowel inflammation, and heart attack.
High-protein diets are designed to provide about 1.5 g of protein for each kilogram of a person's body weight, and a total of about 2,500 calories daily.Complex proteins, such as milk and meats, should make up one-half to two-thirds of the daily protein requirement. High-protein diets are recommended for people who have an increased need for protein due to:
- protein-calorie malnutrition,
- severe stress, or conditions such as AIDS, cancer, or
- burns with high metabolic rates that lead to the loss of large amountsof protein
- certain malabsorption syndromes, celiac disease, or otherdisorders that are characterized by poor food absorption.
A low-protein diet excludes dairy products and meats, and requires that aboutthree-fourths of the daily allowance of protein come from high-value proteinsources. Supplements may be prescribed to prevent amino acid deficiencies. Low-protein diets are used in treatment of cirrhosis and kidney disease.
Dietary modification is the first weapon in the fight against the high cholesterol levels that contribute to heart disease and arteriosclerosis. Doctors usually prescribe one of the three low-cholesterol diets recommended by the American Heart Association. In the preventive diet, total cholesterol intake isless than 300 milligrams per day. The phase 2 diet, recommended for people with mild elevations of blood cholesterol, restricts cholesterol intake to 200milligrams per day. For anyone with severely elevated blood cholesterol levels, the most restrictive diet is recommended, which limits cholesterol intakeeven further. Low-cholesterol diets are prescribed to reduce the risk of heart disease and to treat arteriosclerosis, diabetes, high cholesterol (which may be hereditary and require cholesterol-reducing drugs), and high blood pressure. A low-cholesterol diet is not a cure for the conditions it is prescribed to treat, so most people must stay on the diet for the rest of their lives.
Most American diets contain too much fat. Fat often makes up about 40% (about160 grams) of total calories consumed each day. Most doctors and other experts recommend limiting fat to 30% (about 120 grams) of daily calories, since consumption of too much fat has been linked to obesity, heart disease, and several types of cancer. A low-fat diet usually limits daily fat intake to 50 grams, while an extremely low-fat diet limits fat consumed each day to 25-30 grams. Low-fat diets are recommended to:
- Help prevent heart disease
- Help prevent colon, prostate, and breast cancers
- Help treat a variety of conditions including gout, AIDS, gallbladder disease, liver disease,celiac disease, inflammatory bowel disease, and heartburn.
Gluten and gliadin are proteins found in certain grains and grain-containingproducts. These proteins are toxic to cells within the intestinal tract of anindividual who is "intolerant"; and cause difficulty in food absorption. Celiac disease is caused by intolerance to these proteins. This intolerance causes patients with celiac disease to suffer weight loss, diarrhea, malnutrition, and bloating. By eliminating foods containing gluten from the diet, furtherdamage to the intestines can be prevented, symptoms are relieved, and malabsorption of nutrients is corrected. A gluten-free diet eliminates all foods containing wheat, rye, barley, and malt, and must be followed for life.
This diet restricts food, such as sardines, liver, and eggs that cause the body to produce uric acid. It is usually prescribed as part of a treatment program for gout (a disease usually caused by having too much uric acid in the body) and kidney stones, which also includes exercise and medication. In addition to excluding organ meats (sweetbreads, liver, and kidney) and certain types of fish (anchovies, sardines, mackerel) and limiting the amount of other purine-containing foods such as shrimp, meats, and dairy products, this diet emphasizes drinking about 2 qt of water and fruit juice daily, to promote the excretion of uric acid, and eating fruits and vegetables that increase urine alkalinity and the solubility of uric acid.
On the average, Americans consume about 5,000 milligrams of salt or sodium daily. New guidelines suggest that 2,400 milligrams of sodium should be the upper limit, even if there are no signs of heart disease. Most people with heartdisease should limit their sodium intake to less than 2,000 milligrams a day, and some low-salt diets restrict sodium to as little as 250 milligrams perday. The amount of salt in the diet is important for people who have high blood pressure or congestive heart failure.
Some experts believe excessive intake of salt is a major reason for high blood pressure, especially in Western countries. Excess sodium encourages the body to retain fluid, thereby increasing fluid pumped by the heart and circulating in the bloodstream. Diets high in salt also can be harmful to people withcongestive heart failure because the excess fluid backs up into the lungs, causing congestion.
Potassium chloride is a common ingredient in salt substitutes. But too much potassium can be harmful for people with kidney problems. One way to enhance the flavor of food while eliminating salt is to add lemon juice, herbs, spices, or flavored vinegar.
The amount of food intake by an individual and the level of physical activityhave to be balanced, if a healthy body weight has to be maintained. If a person regularly gets even a little more energy from food than they need, they may start to gain weight and eventually become overweight. Extra energy from food and drink is mostly stored as fat. Obesity is more common in the developed countries as food scarcity is not a problem. Plentiful food and leisure cause an imbalance between energy intake and energy expenditure. People who areoverweight have a higher risk of developing diabetes, hypertension, and cardiovascular disease. Having and maintaining a healthy weight, therefore assumesparamount importance. In addition, society, today places such an emphasis onbeing thin that dieting has become a very normal way of life for many people, mostly women.
At any given time, about one in three women, in America is dieting. Maintaining a healthy weight is definitely advisable, but, it is also very important to follow a safe weight loss plan. Weight control is a very individual problem. As we grow older, the body chemistry changes. Therefore, what works for a 25-year-old girl may not work for a 45-year-old woman. Many factors such a slow metabolism, thyroid imbalance, sluggish liver, blood sugar imbalance, poordigestion and elimination, eating the wrong kinds of foods, over eating and so on may be responsible for causing obesity. The most sensible way to lose weight is to adopt a nutritionally balances, low-calorie diet while increasingthe level of physical activity and modifying the eating patterns.
There are many types of weight loss plans. Some of these fad diets bring immediate weight loss, but much of what is lost initially is water weight. Peopleon these diets may lose muscle rather than fat. If continued for a long period of time, these diets may also cause serious nutritional imbalances. Two ofthe most popular fad diets are:
- High protein diets: these are based on the theory that too many carbohydrates prevent the body from burning fat, and dieters should, therefore, fill up on protein.
- Liquid diets: theseare primarily for people who have problem with limiting food portions. Two meals a day are replaced with liquid shakes made up of skim milk and a powdered drink mix.
Several other diets such as "cabbage soup diets," "grapefruit diet," and "liquid broth fasts" also have several followers. When following any of these diets, it is important to take a daily vitamin-mineral supplement that providesat least 100 percent of the RDAs. A minimum of eight glasses of water shouldbe drunk everyday, especially if following the "high-protein" plan. If dizziness, headaches or any other symptom develops, it is important to quit the diet.
Maintaining a normal healthy weight involves more than counting calories. Modifying the eating behavior, and making certain lifestyle changes are important, if the weight loss has to be permanent. Snacking throughout the day, eating out of habit or boredom, very sedentary life-styles are some of the behaviors that can be changed. It is also important to have a healthy self-image anda willingness to accept oneself for what one is. A successful weight controlprogram involves a combination of diet, exercise, attitude, and behavior. Weight loss goals are crucial, since goals commit one to action and provide themotivation, But, the goals should be reasonable and attainable. If one is serious about losing weight, it is advisable to consult with a doctor or a dietician who can provide one with a program of healthy eating and exercise thatwill bring the desired results.