Make fitness the focus of weight loss efforts

OB/GYN News,  Feb 1, 2003  by Norra MacReady

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SAN FRANCISCO -- Weight management efforts should emphasize making patients more fit rather than less fat, Dr. Robert B. Baron said at a conference on women's health sponsored by the University of California, San Francisco.

When patients are ready to consider losing weight, give them three goals, said Dr. Baron, professor of medicine at the university.

The first goal is to become as fit as possible at their current weight. The second is to prevent further weight gain. "And then, if the patient has made some lifestyle changes in moving toward these goals, we can say, 'Let's look at what some of the options are for weight loss.'"

According to the President's Council on Physical Fitness and Sports, moderate daily exercise sufficient to provide measurable health benefits includes activities such as 30 minutes of brisk walking or raking leaves, 15 minutes of running, or 45 minutes of playing volleyball. More benefits accrue with exercise of greater intensity or duration.

This approach focuses on fitness independent of body size and is more attainable for most patients than a standard weight loss regimen, Dr. Baron said.

It also may prevent much of the excess mortality generally associated with obesity. In the Aerobics Center Longitudinal Study, a 14-year observational study of 25,714 men, fitness level mattered more than weight in raising the risk of mortality: Men who were obese but fit, as measured by their performance on a treadmill test, had only a 10% increase in the risk of all-cause mortality over the next 15 years compared with fit, normal-weight men.

In nonfit men of normal weight, the risk of all-cause mortality was doubled, and in nonfit, obese men it was tripled. Fit, obese men had a 60% increase in the risk of death from cardiovascular causes, but if they were nonfit and obese, the risk jumped fivefold. Nonfit, normal-weight men had a threefold increase in the risk of cardiovascular death (JAMA 282[16]:1547-53, 1999).

Dr. Baron said he believes these findings are applicable to women.

For patients who are ready to lose weight, Dr. Baron prescribes a diet of approximately 1,400 calories per day. Very low-calorie diets, which he defined as those with daily calorie counts of 800 or less, are indicated only for patients who require rapid, short-term weight loss, such as a diabetic with poor glucose control or a patient who must lose weight to undergo surgery. Some patients may also need a dramatic, initial weight loss to motivate them to stay on a long-term program.

In general, however, 48 randomized clinical trials have shown no greater long-term weight loss with very-low-calorie diets than with less restrictive regimens.

Weight loss seems to be faster with diets that derive about half of their calories from fat rather than carbohydrate, but that may be due to greater losses of water and salt. However, patients may find the higher-fat diet easier to follow.

Drug treatment may help patients who already are motivated to make lifestyle changes, Dr. Baron said. He cited National Institutes of Health recommendations that drug treatment be reserved for obese patients (those with a body mass index of at least 30kg/[m.sup.2]), or patients with a body mass index of 27 kg/[m.sup.2] and other comorbidities.

Dr. Baron has found that the results after 1 month of drug treatment are a good predictor of a patient's long-term success, so if a patient's experience isn't satisfactory by then, he discontinues the prescription.

Patients with a body mass index of 40 kg/[m.sup.2] or 35 kg/[m.sup.2] plus other comorbidities may be candidates for gastric bypass surgery. They'll lose as much as 50% of their body weight, but there's also a 30%-50% incidence of adverse effects such as diarrhea, emesis, ulcers, and gallstones. Still, most insurers view the procedure as cost effective and will approve it for selected patients.

Before surgery, Dr. Baron has patients lose about 10% of their body weight by eating 1,000-1,200 calories a day, because that's all they'll be able to consume after the operation. He also warns women of childbearing age that it could complicate pregnancy.

When it comes to weight maintenance, exercise is once again the key, Dr. Baron said. In a survey of people who had lost weight and kept it off, men and women alike engaged in an hour of moderate physical activity every day. They also consumed approximately five small high-carbohydrate, low-fat meals or snacks, regularly monitored their weight, and virtually never ate fast food (Annu. Rev. Nutr. 21:323-41, 2001). The Institute of Medicine's Food and Nutrition Board has based its new recommendations for weight maintenance on these findings (see box).

Always screen a patient for depression or other psychiatric disorders before starting her on any type of weight loss regimen, Dr. Baron said.

Recommendations for Healthy Weight Maintenance

Nutrient                         % of Total Daily Calories

Carbohydrate *                             45-65
Fat **                                     20-35
Protein                                    10-35

Fiber                                  Grams per Day

For people under 50 years old   38 (for men) 25 (for women)
For people over 50 years old    30 (for men) 21 (for women)

Exercise                                  Amount

Moderate (e.g., walking 4 mph)           1 hr/day
Intense (e.g., jogging)         20-30 minutes 4-7 days/wk

* Refined sugars should make up less than 25% of total calories.

** As little saturated fat, trans fat, or cholesterol as possible.

Source: Food and Nutrition Board, Institute of Medicine

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