Medications

Introduction

The cornerstone of losing weight is to eat fewer calories than the amount your body uses during the day. This "calorie deficit" will cause your body to use fat stores as fuel. A calorie deficit of approximately 3,500 kcal is needed to lose 1 lb. of fat tissue. Therefore, if someone eats 1000 kcal less per day than he/she uses up (7,000 kcal less than he/she uses up over a week), this person should lose

approximately two lbs. of fat in one week. In general, 85% of weight that is lost by dieting comes from fat and 15% from lean tissue (muscle).

Several important principles should be considered when trying to lose weight:

  1. Being overweight is a chronic condition and requires long-term treatment for long-term success;
  2. A slow rate of weight loss (<2% body weight loss/week) achieved by consuming a low-calorie diet is safer than a rapid rate of weight loss achieved by consuming a very-low calorie diet (<800 kcal/day);
  3. Behavior modification is necessary for long-term lifestyle changes;
  4. Exercise is an important component of weight management because it is associated with long-term success and may have beneficial cardiovascular and psychological effects;
  5. Modest weight loss (5-10% of initial body weight) has considerable health benefits and should be considered a long-term goal for many people.

Medical Treatment Approaches for Weight Reduction

Dieting

I use several dieting approaches with my obese and overweight patients. The precise diet chosen depends on patient preference, coexisting illnesses, cost, and the calorie deficit desired. In general, the diet should provide adequate protein (at least 0.8 g/kg ideal body weight per day), vitamins and trace minerals. The adequacy of vitamin and trace mineral intake can be ensured by taking multivitamin and trace mineral supplements. Providing adequate fat (5 g to 10 g of fat) in at least one meal each day will stimulate maximal gallbladder function, and will help reduce the increased risk of gallstone formation that occurs with weight loss. [Please see our article, "Selecting a Weight Loss Program," for further information on choosing a proper diet plan.]

Behavior modification

The purpose of behavior therapy is to help patients change patterns of eating and physical activity and to identify specific issues that interfere with their ability to adopt a healthier lifestyle. Standard tools of behavior modification include self-monitoring (recording all food intake every day), stimulus control (identifying situations that lead to excessive food intake and then developing behavior strategies to control or avoid those situations), contingency management (providing rewards for achieving successful behavior changes), stress management (decreasing stressful life factors that make lifestyle changes difficult), and social support (involving selected friends, co-workers, and family members in the effort to lose weight). In general, short-term (20 weeks) behavior modification therapy causes a loss of approximately 1 lb. or 0.5% of body weight per week. However, weight regain usually occurs after behavior modification therapy sessions stop. Providing treatment for longer duration improves long-term outcome.

Exercise

Physical activity is an important component of weight management. Exercise increases the proportion of weight lost as fat and minimizes losses in muscle tissue. It also has significant psychological benefits and is associated with long-term weight management success. Although exercise improves overall fitness and burns calories, the benefits of increasing physical activity on weight loss is probably related more to its effect on food intake than on actual energy expenditure. For example, walking one mile consumes only 100 kcal. A dietary indiscretion could easily negate the caloric impact of this exercise. Therefore, exercise must be incorporated into a broader weight management program in order to be successful.

Drug Therapy

The available medications approved by the Food and Drug Administration (FDA) for the treatment of obesity are "anorexiants." These drugs affect neurotransmitters (chemicals in the brain) involved in the regulation of food intake. Two of these medications, fenfluramine and dexfenfluramine (a form of fenfluramine) have been withdrawn from the marketplace because of the relationship between their use and harmful effects on heart valves (valvular heart disease).

Another medication, sibutramine (trade name is Meridia) was recently approved by the FDA for obesity therapy. Sibutramine works primarily by increasing the levels of two neurotransmitters, norepinephrine and serotonin. Sibutramine treatment was successful in achieving a 10% loss in body weight after 1 year of treatment in 39% of patients, compared with 9% of those given placebo treatment (control group).

Orlistat (trade name is Xenical) is currently under review by the FDA and may be approved in 1999. Orlistat decreases the activity of chemicals present inside the intestine called "lipases." These lipases serve to break down the fat that we eat so that it can be absorbed by the intestine. Absorbed intestinal fat represents absorbed calories. Orlistat decreases total calorie absorption by blocking intestinal fat absorption by about 30%. In 1 year clinical trials, 33% of patients who received Orlistat therapy lost 10% or more of their initial body weight compared with 16% of those that received placebo (control group).

In general, the greatest problem in treating overweight and obese patients is the high rate of relapse. With drug therapy, the most important challenge is to maintain long-term weight loss after the drug is stopped. It may be inappropriate to consider the use of drug therapy as a short-term approach to "get patients going" or "get patients over the hump" because patients who respond to drug therapy usually regain weight when the drug is stopped. This observation implies that effective drug therapy for overweight and obese patients likely needs to be long-term, and perhaps life-long. Therefore, the consideration of drug therapy involves a careful analysis of many factors, including the risks of being obese, the beneficial effects of drug treatment on body weight, the reduction of obesity-related complications, and the side effects of drug treatment.

The available data regarding drug therapy currently available from clinical trials suggest that:

  1. After 6 months, patients often experience a plateau in weight loss despite continued drug treatment;
  2. Discontinuation of therapy in patients who responded to drug treatment results in a rapid increase in body weight;
  3. Drug therapy is still effective when started after initial weight loss is achieved by means other than medication, such as behavioral therapy and dieting;
  4. Drug therapy alone is not as effective as when the drug is given in conjunction with a comprehensive weight management program.

Summary

There are a number of approaches to weight loss reduction. The one absolute rule that I have learned in treating overweight patients is that there is never a simple solution. None of these approaches are usually successful when used independently. I have found that the key to long term weight loss is to incorporate components of each approach into a treatment plan. By learning as much as possible about a particular patient’s physical, psychological, and emotional situation, the patient and the treatment team can focus on those approaches that will most likely deliver results.



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