INTRODUCTION — Obesity is a major international problem and Americans are among the heaviest people in the world. For instance, the percentage of obese people in the United States has risen steadily from 14 percent in the 1976 to 1980 survey to 33.5 percent in the 1999 to 2000 survey .
This topic review discusses how to get started with a weight loss plan, including behavioral plans, diet therapy, and weight loss medications. Weight loss surgery is discussed in a separate topic review.
CONSEQUENCES OF OBESITY — Obesity is associated with many medical problems, most of which improve with weight loss . Both men and women with obesity are at increased risk for the following: Reduced life expectancy Diabetes mellitus Gallstones Hypertension (high blood pressure) Osteoarthritis Coronary heart disease Abnormal blood lipids Stroke Sleep apnea Cancer (colon and prostate cancer in men; uterine and gallbladder cancer in women)
Many people find that they initially lose weight by dieting, although they quickly regain the weight after the diet ends. Because long-term weight reduction is so difficult, it is important to have as much information and support as possible before starting. People who are ready to lose weight and who believe that their body weight can be controlled long-term are usually the most successful.
STARTING A WEIGHT LOSS PROGRAM — Before beginning a weight loss program, you should speak with a healthcare provider so that he/she can help to choose the appropriate treatment, monitor your progress, and provide advice and support along the way.
Determining the severity of the weight problem — In order to know what treatment (or combination of treatments) will work best, a healthcare provider should determine your degree of obesity and distribution of body fat. This can be done by measuring your body mass index (BMI) and waist circumference (measurement). The BMI is calculated from a person's height and weight as follows:
BMI = body weight (in kilograms) / height (in meters) squared. This can also be determined with a calculator . A BMI between 25 and 30 kg/m2 is considered overweight. A BMI greater than 30 kg/m2 is considered to be obese.
A waist circumference greater than 35 inches (88 cm) in women and 40 inches (102 cm) in men indicates that there is an excessive amount of fat in the abdominal area.
Determining the risk for heart disease — The healthcare provider also needs to consider your risk for heart disease before choosing a treatment. For instance: A person with a BMI of 20 to 25 kg/m2 has little or no increased risk for heart disease from obesity unless they have excessive fat in the abdominal area or have gained more than 22 pounds since age 18. A person with a BMI of 25 to 30 kg/m2 has a low risk A person with a BMI of 30 to 35 kg/m2 has a moderate risk A person with a BMI of 35 kg/m2 and above has a high risk
Regardless of a person's BMI, health risks increase if a person: Has excess abdominal fat Has high blood pressure Has high levels of cholesterol in the blood Has heart disease Has a strong family history of diabetes Is male Was obese before age 40
People with the highest risk of heart disease should use the most aggressive weight loss program.
Types of treatment — Depending upon a person's risk factors, BMI, waist circumference, and personal preferences, a healthcare provider will suggest a combination of behavior modification, exercise, dieting, and, in some cases, medications. Surgery is reserved for people with severe obesity who have not responded to other treatments.
SETTING WEIGHT LOSS GOALS — It is important to set a realistic goal for weight loss. The first goal should be to prevent further weight gain and maintain the current weight (within 5 percent). The healthcare provider can help to identify a realistic weight-loss goal. Many people have a "dream" weight that is difficult or impossible to achieve.
A realistic goal — A person at high risk for developing diabetes mellitus who loses 5 percent of their body weight and maintains this weight will reduce their risk for diabetes by about 50 percent. This is a success. Losing more than 15 percent of initial body weight and maintaining this loss is an extremely good result, even if the person never reaches his or her "dream" or "ideal" weight.
BEHAVIOR CHANGES — Behavior change (modification) programs are usually run by psychologists or other trained behavioral professionals. The goals of behavior modification are to help people change their eating habits, increase physical activity, and become more conscious of both of these activities, thereby helping to make healthier choices.
This type of treatment can be broken down into three components: The triggers that make a person want to eat The behavior of eating The consequences of eating
Triggers to eat — Determining what triggers a person to eat involves identifying the foods that a person eats and the settings in which eating occurs. To determine triggers, keep a record for a few days of everything you eat, the places where you eat, how often you eat, and the emotions you were feeling when you ate.
For some people, the trigger is related to a certain time of the day or night. For others, the trigger is related to a certain place, like sitting at a desk working.
Behavior of eating — This component uses stimulus control to break the chain of events between the trigger for eating and eating itself. There are many ways to provide stimulus control. For instance, a person can: Restrict or limit the places they eat Restrict the number of utensils (eg, only a fork) used for eating Drink a sip of water between each bite Chew the food a defined number of times Get up and stop eating every few minutes.
Consequences of eating — This component involves rewarding good eating behaviors. This is not a reward for weight loss; instead, it is a reward for changing unhealthy behaviors.
Food should never be used as a reward. Some people find money, clothing, or personal care (eg, a hair cut, manicure, or massage) to be effective rewards. The reward should be given immediately after the improved behavior to reinforce the value of the good behavior.
Behavior goals need to be clearly defined, and there must be an agreed-upon timeframe for achieving goals. It is often important to reward small changes along the way to the final goal.
Other factors that contribute to successful weight loss — Behavior modification is more than just changing unhealthy eating habits; it also includes developing an internal and external support system, reducing stress, and learning to be assertive. Establishing a "buddy" system — Having a friend or family member available to provide support and reinforce good behavior changes is very helpful. The support person needs to be sympathetic to the person's goals and can be trained by the program director or the person losing weight. Learning to be assertive — It is important to provide opportunities for role-playing in difficult situations. For instance, people trying to lose weight need to learn how to refuse food offered at parties and social gatherings. One strategy is to use assertiveness training, a technique for learning how to say "no" and continuing to say no when urged to eat. Role playing can be done with a partner or in a group. Develop a support system — Having a support system is helpful when losing weight. This is why many commercial groups are successful. Family support is also essential, since negative attitudes about losing weight can slow or even prevent success. Positive thinking — People often have conversations with themselves in their head; these conversations can be positive or negative. If a person eats a piece of cake that is not on their weight loss program, they may respond by thinking, "Oh, you stupid idiot, you've blown your diet!" and, as a result they may eat more cake. A positive thought for the same event could be, "Well, I have eaten cake when it was not on my plan and now I should do something to get back on track." This positive approach is much more likely to be successful than negative, self-deprecatory thoughts. Stress reduction — Although stress is a part of everyday life, it can trigger uncontrolled eating in some people. It is important to find a way to get through these difficult times without eating or by eating low-calorie food, like raw vegetables. It may be helpful to identify a relaxing place that allows a temporary escape from stress. With deep breaths and closed eyes, the person can imagine this relaxing place for a few minutes. Self-help programs — Self-help programs like Weight Watchers, Overeaters Anonymous, and Take Off Pounds Sensibly (TOPS), work for some people. However, these programs have a high drop-out rate. Psychotherapy — Behavioral treatments, including individual psychoanalysis, family or couples training, and self-help groups can help with weight loss efforts.
DIET THERAPY — A calorie is a unit of energy found in food. The body needs calories to function. If a person takes in more calories than they use, approximately 75 percent of the extra calories are stored as fat and the remaining 25 percent as lean tissue. The goal of any diet is to burn up more calories than are taken in, which results in weight loss.
The rate at which a person loses weight can vary: the heavier the person, the quicker the weight loss on any given diet. Weight loss also can be influenced by age and sex. Men lose more weight than women of similar height and weight when dieting because they have more lean body mass and, therefore, use more energy. Older people have a slower metabolism than young people, and thus lose weight at a slower rate.
Conventional diets — Conventional weight reduction diets provide at least 800 calories a day, but less than what the body requires. These diets fall into four groups: Balanced low-calorie diets / portion-controlled diets Low-carbohydrate diets Low-fat diets Fad diets (these are diets that involve unusual food combinations or eating certain foods in a particular order)
Diets in the range of 1,200 to 1,500 calories are suitable for most people; men should eat a diet with close to 1,500 calories per day while women should eat a diet with close to 1,200 calories per day.
Balanced low-calorie diets — When starting a diet, it is important to determine an appropriate calorie level, as well as a combination of foods, to meet an individual weight loss goal. It is best to choose foods that contain adequate protein, carbohydrates, essential fatty acids, and vitamins. Alcohol, sugar-containing beverages, and most highly concentrated sweets (candy, cakes, cookies) should be eliminated from weight-loss diets since they rarely contain adequate amounts of nutrients other than calories.
Portion-controlled diets — One simple way to diet is to buy packaged foods, like frozen low-calorie meals. This can be supplemented with formula diets using powdered or liquid drinks. A typical meal plan for one day may include a formula diet or breakfast bar for breakfast, a formula diet or a frozen meal for lunch, and a frozen calorie-controlled entree for dinner. This would give the person 1,000 to 1,500 calories per day.
Low-fat diets — High fat diets, especially diets that are high in saturated and trans fat foods, increase the risk of obesity, heart disease, and certain forms of cancer, among other adverse effects. Almost all dietary guidelines recommend limiting fat intake to 30 percent of total calories or less.
A low-fat diet can be implemented in two ways. First, a dietitian can provide a specific menu plans that emphasizes the use of reduced fat foods. As one guideline, if a food "melts" in the mouth, it probably has fat in it. Second, a person can learn how to count fat grams. Many experts recommend keeping calories from fat to below 30 percent of total calories. For a 1500 calorie diet, this would mean about 45 g or less of fat, which can be counted using the nutrition information labels on food packages.
Low-carbohydrate diets — Carbohydrates are found in fruits, vegetables and grains (including breads, rice, pasta, and cereal), alcoholic beverages, and in dairy products. Meat and fish do not contain carbohydrates. Low-carbohydrate diets (eg. Atkins diet, South Beach Diet) have become extremely popular as a way to lose weight quickly. With a low-carbohydrate diet, between zero and 60 grams of carbohydrates are eaten per day (as compared to a standard adult diet which contains approximately 200 to 300 grams of carbohydrates).
Very low carbohydrate diets may be associated with more frequent side effects than low-fat diets. In one clinical trial, constipation, headache, bad breath, muscle cramps, diarrhea, general weakness, and rash occurred significantly more frequently in the low-carbohydrate compared to the low-fat diet group .
Diet comparison — One trial compared four different diets: (very low-carbohydrate [Atkins], macronutrient balance controlling glycemic load [Zone], calorie restriction [Weight Watchers], and very low-fat [Ornish]) . Average weight loss at one year for those who completed the study was approximately 4 to 7 kg (8.8 to 15.4 lbs), and was not different between the four diets.
Higher dropout rates were noted after one year with the very low-carbohydrate and very low-fat diets compared to the more moderate diets (48 percent for Atkins, 50 percent for Ornish, and 35 percent for Weight Watchers and Zone).
Fad diets — Fad diets often promise quick weight loss (more than 1 to 2 pounds per week), claim that it's unnecessary to exercise or give up favorite foods, limit food choices, or require the person to pay large amounts of money for seminars or pills. They generally lack any scientific evidence that they are safe and effective, but instead rely on "before" and "after" photos.
Diets that sound too good to be true usually are; these plans are a waste of time and money and are not recommended. A healthcare provider or nutritionist can help determine a safe and effective way to lose weight and keep it off.
WEIGHT LOSS MEDICATIONS — Drug therapy may be helpful for some obese people when used in combination with diet, exercise, and behavior modification. People who are overweight who want to start a weight loss medication must carefully evaluate the risks and benefits with a healthcare provider. There are situations in which drug therapy is appropriate; as an example: People who are obese (BMI > 30 kg/m2) (show calculator) Overweight people (BMI between 27 and 30 kg/m2) who have other medical problems such as diabetes, high cholesterol, or high blood pressure, which further increase the risk of heart disease.
Goals of drug therapy — The goals of any weight loss program, including drug therapy, must be realistic: It is unrealistic to expect body weight to return to "normal". Weight loss should be greater than 2 kg (approximately 5 pounds) during the first month of drug therapy in order for it to be continued. Weight loss of 10 to 15 percent is considered a good response; weight loss exceeding 15 percent is considered an excellent response.
There are two drugs available for the long-term treatment of obesity; a third drug is in the final stages of becoming approved.
Sibutramine — Sibutramine (Meridia®, Reductil®) is an appetite suppressant that is effective for many people. The recommended starting dose is 5 to 10 mg per day; doses above 15 mg per day are not recommended. In people who complete one year of therapy, the average weight loss is 10 percent of the initial body weight (5 percent more than those who took a placebo treatment).
Side effects include insomnia, dry mouth, and constipation. Increases in blood pressure can occur. Therefore, the blood pressure is usually monitored during treatment. Sibutramine is not recommended for people with a history of heart disease or stroke. There is no evidence that sibutramine causes cardiac valve abnormalities or pulmonary hypertension (like dexfenfluramine and fenfluramine (Phen/Fen)).
Orlistat — Orlistat (Xenical® 120 mg capsules) is a medication that reduces fat absorption and helps some obese people to lose weight. A lower dose version is now available without a prescription (Alli® 60 mg capsules) in many countries, including the United States. The medication is recommended three times per day, taken with a meal; a dose may be skipped if a meal is skipped or if the meal contains no fat.
After one year of treatment with orlistat, the average weight loss is approximately 8 to 10 percent of initial body weight (4 percent more than those who took a placebo). Cholesterol levels often improve and blood pressure sometimes fall. In people with diabetes, orlistat may help control blood glucose levels.
Side effects occur in 15 to 10 percent of people, and may include stomach cramps, gas, diarrhea, leakage of stool, or oily stools. These problems are more likely when orlistat is taken with a high fat meal (if more than 30 percent of calories in the meal are from fat). Side effects are usually mild and subside as people learn how to avoid these problems by avoiding high fat diets and sticking to the recommended intake of no more than 30 percent fat.
Rimonabant — Rimonabant (Accomplia®) is a cannabinoid receptor antagonist. It was developed based upon the idea that people who smoke marijuana (cannabis) often develop extreme hunger. Rimonabant blocks cannabis receptors in the brain, which reduces appetite. In one clinical study, it produced 8 to 9 percent weight loss after one year (5 percent better than placebo). Blood pressure, HDL-cholesterol, triglycerides, and metabolic syndrome typically improve during treatment.
Side effects of rimonabant can include anxiety and depression. It is available in Europe but is not yet available in the United States.
Diet supplements — Over-the-counter dietary supplements are widely used by people who are trying to lose weight, although the safety and efficacy of these supplements are unproven. Examples of dietary supplements include ephedra (described below, no longer available), green tea, chromium, chitosan, and wheat dextrin. Ephedra, a compound related to ephedrine, is no longer available in the United States due to safety concerns. Many over-the-counter diet pills previously contained ephedra. Although some studies have shown that ephedra sometimes helps with weight loss, there can be serious side effects (psychiatric symptoms, palpitations, and gastrointestinal symptoms), including death. Chitosan and wheat dextrin are ineffective for weight loss, and their use is not recommended. There are not enough data regarding the safety and efficacy of chromium, ginseng, glucomannan, green tea, hydroxycitric acid, L carnitine, psyllium, pyruvate supplements, St. Johns wort, and conjugated linoleic acid. Until more information is available, these supplements are not recommended for the purpose of weight loss. Two compounded dietary supplements imported from Brazil, Emagrace Sim (also known as the Brazilian diet pill) and Herbathin dietary supplement, have been shown to contain prescription drugs. The Food and Drug Administration has warned of the potential danger of this supplement. Hoodia gordonii, a dietary supplement derived from a desert plant in South Africa, is marketed and sold as an appetite suppressant. However, it has not been proven safe or effective.
A realistic goal — A person at high risk for developing diabetes mellitus who loses 5 percent of their body weight and maintains this weight will reduce their risk for diabetes by about 50 percent. This is a success. Losing more than 15 percent of initial body weight and maintaining this loss is an extremely good result, even if the person never reaches his or her "dream" or "ideal" weight.
BEHAVIOR CHANGES — Behavior change (modification) programs are usually run by psychologists or other trained behavioral professionals. The goals of behavior modification are to help people change their eating habits, increase physical activity, and become more conscious of both of these activities, thereby helping to make healthier choices.
This type of treatment can be broken down into three components: The triggers that make a person want to eat The behavior of eating The consequences of eating
Triggers to eat — Determining what triggers a person to eat involves identifying the foods that a person eats and the settings in which eating occurs. To determine triggers, keep a record for a few days of everything you eat, the places where you eat, how often you eat, and the emotions you were feeling when you ate.
For some people, the trigger is related to a certain time of the day or night. For others, the trigger is related to a certain place, like sitting at a desk working.
Behavior of eating — This component uses stimulus control to break the chain of events between the trigger for eating and eating itself. There are many ways to provide stimulus control. For instance, a person can: Restrict or limit the places they eat Restrict the number of utensils (eg, only a fork) used for eating Drink a sip of water between each bite Chew the food a defined number of times Get up and stop eating every few minutes.
Consequences of eating — This component involves rewarding good eating behaviors. This is not a reward for weight loss; instead, it is a reward for changing unhealthy behaviors.
Food should never be used as a reward. Some people find money, clothing, or personal care (eg, a hair cut, manicure, or massage) to be effective rewards. The reward should be given immediately after the improved behavior to reinforce the value of the good behavior.
Behavior goals need to be clearly defined, and there must be an agreed-upon timeframe for achieving goals. It is often important to reward small changes along the way to the final goal.
Other factors that contribute to successful weight loss — Behavior modification is more than just changing unhealthy eating habits; it also includes developing an internal and external support system, reducing stress, and learning to be assertive. Establishing a "buddy" system — Having a friend or family member available to provide support and reinforce good behavior changes is very helpful. The support person needs to be sympathetic to the person's goals and can be trained by the program director or the person losing weight. Learning to be assertive — It is important to provide opportunities for role-playing in difficult situations. For instance, people trying to lose weight need to learn how to refuse food offered at parties and social gatherings. One strategy is to use assertiveness training, a technique for learning how to say "no" and continuing to say no when urged to eat. Role playing can be done with a partner or in a group. Develop a support system — Having a support system is helpful when losing weight. This is why many commercial groups are successful. Family support is also essential, since negative attitudes about losing weight can slow or even prevent success. Positive thinking — People often have conversations with themselves in their head; these conversations can be positive or negative. If a person eats a piece of cake that is not on their weight loss program, they may respond by thinking, "Oh, you stupid idiot, you've blown your diet!" and, as a result they may eat more cake. A positive thought for the same event could be, "Well, I have eaten cake when it was not on my plan and now I should do something to get back on track." This positive approach is much more likely to be successful than negative, self-deprecatory thoughts. Stress reduction — Although stress is a part of everyday life, it can trigger uncontrolled eating in some people. It is important to find a way to get through these difficult times without eating or by eating low-calorie food, like raw vegetables. It may be helpful to identify a relaxing place that allows a temporary escape from stress. With deep breaths and closed eyes, the person can imagine this relaxing place for a few minutes. Self-help programs — Self-help programs like Weight Watchers, Overeaters Anonymous, and Take Off Pounds Sensibly (TOPS), work for some people. However, these programs have a high drop-out rate. Psychotherapy — Behavioral treatments, including individual psychoanalysis, family or couples training, and self-help groups can help with weight loss efforts.
DIET THERAPY — A calorie is a unit of energy found in food. The body needs calories to function. If a person takes in more calories than they use, approximately 75 percent of the extra calories are stored as fat and the remaining 25 percent as lean tissue. The goal of any diet is to burn up more calories than are taken in, which results in weight loss.
The rate at which a person loses weight can vary: the heavier the person, the quicker the weight loss on any given diet. Weight loss also can be influenced by age and sex. Men lose more weight than women of similar height and weight when dieting because they have more lean body mass and, therefore, use more energy. Older people have a slower metabolism than young people, and thus lose weight at a slower rate.
Conventional diets — Conventional weight reduction diets provide at least 800 calories a day, but less than what the body requires. These diets fall into four groups: Balanced low-calorie diets / portion-controlled diets Low-carbohydrate diets Low-fat diets Fad diets (these are diets that involve unusual food combinations or eating certain foods in a particular order)
Diets in the range of 1,200 to 1,500 calories are suitable for most people; men should eat a diet with close to 1,500 calories per day while women should eat a diet with close to 1,200 calories per day.
Balanced low-calorie diets — When starting a diet, it is important to determine an appropriate calorie level, as well as a combination of foods, to meet an individual weight loss goal. It is best to choose foods that contain adequate protein, carbohydrates, essential fatty acids, and vitamins. Alcohol, sugar-containing beverages, and most highly concentrated sweets (candy, cakes, cookies) should be eliminated from weight-loss diets since they rarely contain adequate amounts of nutrients other than calories.
Portion-controlled diets — One simple way to diet is to buy packaged foods, like frozen low-calorie meals. This can be supplemented with formula diets using powdered or liquid drinks. A typical meal plan for one day may include a formula diet or breakfast bar for breakfast, a formula diet or a frozen meal for lunch, and a frozen calorie-controlled entree for dinner. This would give the person 1,000 to 1,500 calories per day.
Low-fat diets — High fat diets, especially diets that are high in saturated and trans fat foods, increase the risk of obesity, heart disease, and certain forms of cancer, among other adverse effects. Almost all dietary guidelines recommend limiting fat intake to 30 percent of total calories or less.
A low-fat diet can be implemented in two ways. First, a dietitian can provide a specific menu plans that emphasizes the use of reduced fat foods. As one guideline, if a food "melts" in the mouth, it probably has fat in it. Second, a person can learn how to count fat grams. Many experts recommend keeping calories from fat to below 30 percent of total calories. For a 1500 calorie diet, this would mean about 45 g or less of fat, which can be counted using the nutrition information labels on food packages.
Low-carbohydrate diets — Carbohydrates are found in fruits, vegetables and grains (including breads, rice, pasta, and cereal), alcoholic beverages, and in dairy products. Meat and fish do not contain carbohydrates. Low-carbohydrate diets (eg. Atkins diet, South Beach Diet) have become extremely popular as a way to lose weight quickly. With a low-carbohydrate diet, between zero and 60 grams of carbohydrates are eaten per day (as compared to a standard adult diet which contains approximately 200 to 300 grams of carbohydrates).
Very low carbohydrate diets may be associated with more frequent side effects than low-fat diets. In one clinical trial, constipation, headache, bad breath, muscle cramps, diarrhea, general weakness, and rash occurred significantly more frequently in the low-carbohydrate compared to the low-fat diet group .
Diet comparison — One trial compared four different diets: (very low-carbohydrate [Atkins], macronutrient balance controlling glycemic load [Zone], calorie restriction [Weight Watchers], and very low-fat [Ornish]) . Average weight loss at one year for those who completed the study was approximately 4 to 7 kg (8.8 to 15.4 lbs), and was not different between the four diets.
Higher dropout rates were noted after one year with the very low-carbohydrate and very low-fat diets compared to the more moderate diets (48 percent for Atkins, 50 percent for Ornish, and 35 percent for Weight Watchers and Zone).
Fad diets — Fad diets often promise quick weight loss (more than 1 to 2 pounds per week), claim that it's unnecessary to exercise or give up favorite foods, limit food choices, or require the person to pay large amounts of money for seminars or pills. They generally lack any scientific evidence that they are safe and effective, but instead rely on "before" and "after" photos.
Diets that sound too good to be true usually are; these plans are a waste of time and money and are not recommended. A healthcare provider or nutritionist can help determine a safe and effective way to lose weight and keep it off.
WEIGHT LOSS MEDICATIONS — Drug therapy may be helpful for some obese people when used in combination with diet, exercise, and behavior modification. People who are overweight who want to start a weight loss medication must carefully evaluate the risks and benefits with a healthcare provider. There are situations in which drug therapy is appropriate; as an example: People who are obese (BMI > 30 kg/m2) (show calculator) Overweight people (BMI between 27 and 30 kg/m2) who have other medical problems such as diabetes, high cholesterol, or high blood pressure, which further increase the risk of heart disease.
Goals of drug therapy — The goals of any weight loss program, including drug therapy, must be realistic: It is unrealistic to expect body weight to return to "normal". Weight loss should be greater than 2 kg (approximately 5 pounds) during the first month of drug therapy in order for it to be continued. Weight loss of 10 to 15 percent is considered a good response; weight loss exceeding 15 percent is considered an excellent response.
There are two drugs available for the long-term treatment of obesity; a third drug is in the final stages of becoming approved.
Sibutramine — Sibutramine (Meridia®, Reductil®) is an appetite suppressant that is effective for many people. The recommended starting dose is 5 to 10 mg per day; doses above 15 mg per day are not recommended. In people who complete one year of therapy, the average weight loss is 10 percent of the initial body weight (5 percent more than those who took a placebo treatment).
Side effects include insomnia, dry mouth, and constipation. Increases in blood pressure can occur. Therefore, the blood pressure is usually monitored during treatment. Sibutramine is not recommended for people with a history of heart disease or stroke. There is no evidence that sibutramine causes cardiac valve abnormalities or pulmonary hypertension (like dexfenfluramine and fenfluramine (Phen/Fen)).
Orlistat — Orlistat (Xenical® 120 mg capsules) is a medication that reduces fat absorption and helps some obese people to lose weight. A lower dose version is now available without a prescription (Alli® 60 mg capsules) in many countries, including the United States. The medication is recommended three times per day, taken with a meal; a dose may be skipped if a meal is skipped or if the meal contains no fat.
After one year of treatment with orlistat, the average weight loss is approximately 8 to 10 percent of initial body weight (4 percent more than those who took a placebo). Cholesterol levels often improve and blood pressure sometimes fall. In people with diabetes, orlistat may help control blood glucose levels.
Side effects occur in 15 to 10 percent of people, and may include stomach cramps, gas, diarrhea, leakage of stool, or oily stools. These problems are more likely when orlistat is taken with a high fat meal (if more than 30 percent of calories in the meal are from fat). Side effects are usually mild and subside as people learn how to avoid these problems by avoiding high fat diets and sticking to the recommended intake of no more than 30 percent fat.
Rimonabant — Rimonabant (Accomplia®) is a cannabinoid receptor antagonist. It was developed based upon the idea that people who smoke marijuana (cannabis) often develop extreme hunger. Rimonabant blocks cannabis receptors in the brain, which reduces appetite. In one clinical study, it produced 8 to 9 percent weight loss after one year (5 percent better than placebo). Blood pressure, HDL-cholesterol, triglycerides, and metabolic syndrome typically improve during treatment.
Side effects of rimonabant can include anxiety and depression. It is available in Europe but is not yet available in the United States.
Diet supplements — Over-the-counter dietary supplements are widely used by people who are trying to lose weight, although the safety and efficacy of these supplements are unproven. Examples of dietary supplements include ephedra (described below, no longer available), green tea, chromium, chitosan, and wheat dextrin. Ephedra, a compound related to ephedrine, is no longer available in the United States due to safety concerns. Many over-the-counter diet pills previously contained ephedra. Although some studies have shown that ephedra sometimes helps with weight loss, there can be serious side effects (psychiatric symptoms, palpitations, and gastrointestinal symptoms), including death. Chitosan and wheat dextrin are ineffective for weight loss, and their use is not recommended. There are not enough data regarding the safety and efficacy of chromium, ginseng, glucomannan, green tea, hydroxycitric acid, L carnitine, psyllium, pyruvate supplements, St. Johns wort, and conjugated linoleic acid. Until more information is available, these supplements are not recommended for the purpose of weight loss. Two compounded dietary supplements imported from Brazil, Emagrace Sim (also known as the Brazilian diet pill) and Herbathin dietary supplement, have been shown to contain prescription drugs. The Food and Drug Administration has warned of the potential danger of this supplement. Hoodia gordonii, a dietary supplement derived from a desert plant in South Africa, is marketed and sold as an appetite suppressant. However, it has not been proven safe or effective.
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