SAN FRANCISCO — Helping patients, even overweight patients, to avoid gaining more weight is an important therapeutic goal by itself, Dr. Robert Baron said at a diabetes update sponsored by the University of California, San Francisco.
“It's very, very hard to get people to lose weight. Our priority in a large number of our patients should be to prevent further weight gain,” said Dr. Baron, professor of medicine at the university. “In our society, the default position is to gain weight. You need to have a strategy to maintain your weight, especially [with age].”
Recent data support the classic goals of being as fit as possible at one's current weight, preventing weight gain, and then considering attempts at weight loss, he emphasized. Being overweight by itself is not necessarily a risk factor for mortality, other data show. The presence or absence of metabolic syndrome plays a key role in level of risk.
A 2005 meta-analysis of three National Health and Nutrition Examination Surveys (NHANES I, II and III) found no increased risk for mortality in people who fit the conventional definition of overweight for white people (a body mass index [kg/m2] of at least 25 but less than 30), although the mortality risk did increase among the obese.
Although the prevalence of obesity has increased, the mortality risk associated with obesity decreased between the first of the three surveys, NHANES I, and the more recent NHANES III, although this could be because of methodologic differences.
Data from a separate study in 2005 of 19,173 men showed that the presence of metabolic syndrome doubled the risk for mortality in normal-weight people, added about 50% in absolute risk for death in overweight people, and increased risk for death by 13% in obese people.
Overweight patients may not be at increased risk if they are metabolically normal, but the presence of the metabolic syndrome or other signs of insulin-resistance changes the clinical picture, Dr. Baron said. “Your BMI is your initial screening test, and evaluation of metabolic syndrome becomes your more accurate, second-level test to sort out which patients in the overweight category and Class I obese [BMI of at least 30 but lower than 35] need more particularly aggressive interventions.”
Data on 3,000 successful dieters (mostly white women) who enrolled in the National Weight Control Registry and maintained a 30-pound or greater weight loss for 1 year showed three key steps to keeping the pounds off: high levels of physical activity; diets low in fat and high in fiber, and regular self-monitoring of weight.
Most of the patients did an hour a day of moderately intense exercise, 6–7 days a week, to burn 2,545 kcal/week for women or 3,293 kcal/week for men. Most checked their weight daily or weekly.
Their “grazing” diets consisted of five meals or snacks a day, providing 1,381 kcal/day from foods made up of 24% fat, 19% protein, and 56% carbohydrates. The calorie levels of their weight maintenance diets were similar to those during their weight loss.