Like the 'black and white' approach: teen compliance higher with low-carb diets.(Clinical Rounds)

ST. LOUIS -- Carbohydrate-controlled diets appear to be a safe and effective method of weight loss for overweight adolescents, who respond well to this "black and white" approach to eating and to the diets' lack of emphasis on portion control.

"Teenagers don't like to be told to count points or calories," Dr. Stephen Sondike said at the annual meeting of the Society for Adolescent Medicine. "They like to be told. 'This is what you can have, this is what you can't have. Now knock yourself out.'"

The immediate feedback with such diets also appeals to adolescents, said Dr. Sondike, director of the NEW (Nutrition, Exercise, and Weight Management) Kids Program at Children's Hospital of Wisconsin. Within 3 days, the patient can have a simple urine test for ketones, which will reveal whether they're doing the diet right, he said.

While acknowledging the controversy surrounding low-carbohydrate diets, Dr. Sondike said such eating plans do appear more effective than low-fat or restricted-calorie diets--at least in the short term.

A number of studies--including his own study published in 2003--have shown that controlled-carbohydrate diets result in greater initial weight loss than low-fat diets. However, he said, long-term research indicates that after 1 year of dieting, weight loss is similar between diets that restrict carbohydrates, fat, or calories. But a diet that's more palatable, less restrictive, and satisfies larger appetites, such as a controlled-carbohydrate diet, may be easier for teens to stick to in the long run.

Dr. Sondike's study compared weight loss and lipid profiles in 30 adolescents who followed either a low-fat or a low-carbohydrate diet for 12 weeks. The subjects were 14-15 years old with an average body mass index of 35.5.

The low-carbohydrate group was instructed to consume less than 20 grams of carbohydrate per day for 2 weeks, and then less than 40 grams per day for 10 weeks (adding fruits, nuts, and whole grains), and to eat low-carbohydrate foods according to hunger. The low-fat group was instructed to consume less than 30% of energy from fat. Diet composition and weight were monitored and recorded every 2 weeks.