Healthnotes Newswire (January 25, 2001)—Many doctors give overweight patients a pill, a pep talk, and a pamphlet about diet and exercise. But that combination leads only to minor weight loss, according to a report published in the current issue of Archives of Internal Medicine.¹ When overweight people also attend weekly group sessions aimed at changing eating and exercise patterns, keep daily records of food intake and exercise, and eat a specific low calorie diet, the outcome is much more successful.

Fifty-three women, who weighed an average of 222 pounds at the beginning of the one-year trial, were assigned to one of three groups. All groups received the weight-loss drug sibutramine (Meridia^®).

The first group was instructed to consume a diet containing 1,200–1,500 calories per day and was encouraged to get some exercise, particularly walking, four or five times per week for 30 to 40 minutes each time. In addition, they were given a booklet on healthful eating. But at the end of the year, average weight loss was only nine pounds.

The second group received the same treatment as the first group, but in addition, they attended group sessions once per week for the first 20 weeks. During those sessions, they were given information and help regarding how to make lifestyle changes that would support their weight loss. Such changes may include shopping from a list, storing foods out of sight, keeping portion sizes under control, and avoiding fast-food restaurants. From week 24 until the end of the year, group members attended monthly sessions focusing on how to maintain weight loss. They were also asked to record their food intake and exercise for at least the first 16 weeks of the trial. At the end of the year, average weight loss was almost 25 pounds.

The third group received the same treatment as the second group, except during the first 16 weeks, during which time they were given a special very-low-calorie diet. The diet contained only 1,000 calories per day—about half what some adults need to maintain normal body weight. The diet consisted of four servings per day of a calorie-controlled liquid nutritional formula called OPTIFAST^® plus one portion-controlled evening meal containing a frozen food entrée, fruit, and a salad. Members of this group lost an average of 37 pounds by the end of the year.

The findings of this trial show that most weight loss results from lifestyle education, caloric restriction, and exercise––not from the use of a weight-loss drug. Despite significant weight loss, however, the average woman completing the yearlong trial experienced a significant increase in blood pressure––a rise of 5 (systolic pressure) over 6 (diastolic pressure). The increase in blood pressure might well have been even worse if the drug dose had not been reduced in four patients and discontinued in a fifth.

Weight loss is generally known to lower blood pressure––not raise it. One of the chief reasons overweight patients are encouraged to lose weight is to lower their blood pressure, and by so doing, reduce their risk of heart disease and stroke. What went wrong in this study? Sibutramine is known to increase blood pressure^{2 3} despite its ability to facilitate weight loss. Therefore, for people with high blood pressure––a very common finding in obese patients––sibutramine’s minor contribution to weight loss may be overshadowed by its adverse effects on blood pressure.

Sibutramine reduces appetite without interfering with absorption of food. It creates this effect by interfering with the body’s ability to break down two hormones: norepinephrine and serotonin. As a result of sibutramine’s actions, levels of both hormones rise, leading to a feeling of fullness.