麻豆传媒

HOUSTON -- Obese adults lost significantly more weight by starting the day with a calorie- and carbohydrate-heavy breakfast that included a sweet treat, instead of saving more calories for dinner, according to a study reported here.

Patients who consumed the high-calorie breakfast lost an average of 45 lbs. in 8 months, whereas those assigned to a low-calorie, low-carb breakfast had a mean weight loss of just 8 lbs., after taking into account a 22-pound gain during the 4-month maintenance phase.

The front-loaded diet was associated with significantly greater suppression of the hunger-promoting hormone ghrelin after breakfast. Patients subjectively reported less hunger and fewer cravings, which investigator Daniela Jakubowicz, MD, attributed to meal composition and suppression of cravings by the breakfast treat.

"A high-carbohydrate and protein breakfast may prevent weight regain by reducing diet-induced compensatory changes in hunger, cravings, and ghrelin suppression," Jakubovicz, of Wolfson Medical Center in Tel Aviv, Israel, said at a press briefing during ENDO 2012.

"To achieve long-term weight loss, meal timing and composition must counteract weight-loss compensatory mechanisms which encourage weight regain after weight loss."

The findings are the latest in Jakubowicz's ongoing examination of how meal composition affects weight loss, satiety, and food cravings. 4 years ago at the same meeting, she reported similar results from a study that compared a high- and low-calorie breakfast as part of a low-calorie diet.

The just-completed investigation once again compared high- and low-calorie breakfasts, but with modifications in nutrient composition and total calories from the earlier study.

Jakubowicz and her colleagues randomized 193 obese, nondiabetic patients to food plans that had identical daily calorie allowances: 1,400 for women and 1,600 for men. However, women in one group followed a plan that allocated 600 calories to breakfast, 500 to lunch, and 300 to dinner, whereas the other group had a reverse calorie plan -- 300 for breakfast, 500 for lunch, and 600 for dinner.

Men followed similar diets, including 600 calories versus 300 calories for breakfast, 600 calories for lunch, and 400 calories versus 700 calories for dinner.

The high-calorie breakfast included 60 grams of carbohydrate, as compared with 15 grams in the low-calorie breakfast. Patients assigned to the high-calorie breakfast also consumed 45 grams of protein daily versus 30 grams in the comparison group. The high-calorie breakfast incorporated some type of sweet treat on a daily basis -- a doughnut, candy, cookies, a piece of cake, etc.

Men and women in the high calorie-breakfast group consumed about 20% of daily calories as carbohydrate, 48% to 49% as protein, and 31% to 32% as fat.

In the low calorie-breakfast arm, carbohydrates accounted for 11% of calories in women and 13% in men. Respective values for protein were 52% and 44%, and for fat, 38% and 43.5%.

The study consisted of two phases: a 16-week intervention period, followed by 16 weeks of maintenance. In addition to weight loss, outcomes of interest included metabolic parameters (glucose, insulin, lipids, and ghrelin) and results of objective and patient-reported assessments of hunger, satiety, and cravings.

Both groups lost weight during the first 16 weeks: 30 lbs. with the high-calorie breakfast and 33 lbs. with the low-calorie breakfast.

During the maintenance phase, patients assigned to the high-calorie breakfast lost an additional 15 lbs. whereas the low-calorie breakfast was associated with a 22-pound weight gain (P=0.005).

The high-calorie breakfast was also associated with a 45.2% reduction in ghrelin levels as compared with 29.5% in the low calorie-breakfast group (P<0.0001).

All of the patient-reported outcomes showed significant advantages in favor of the high-calorie breakfast (P<0.0001).

The trial primarily examined the effect of meal composition (calories and nutrients), but Jakubowicz also reported findings from a study that specifically evaluated the impact of meal timing on weight loss and other outcomes.

The study included 93 nondiabetic women who had a mean body mass index of 32 at baseline. The nutrient composition and total calories were the same as in the larger study, but the morning and evening meals were changed.

The high-calorie breakfast increased to 700 calories, whereas dinner decreased to 200 calories. The values were reversed in the group randomized to the low-calorie breakfast.

At the end of 12 weeks, weight loss and change in weight circumference both showed significant advantages in favor of the high-calorie breakfast (P<0.0001). As in the larger study, laboratory parameters also favored the high-calorie breakfast, including glucose, insulin, and ghrelin (P<0.001 for all comparisons), as did self-reported hunger and satiety (P<0.001).

Analysis of patients' lipid profile showed additional benefits in association with the high-calorie breakfast, as total cholesterol, LDL, and triglycerides all declined significantly more among patient assigned to the high-calorie breakfast (P<0.001).