|Study authors examined whether a stepped-care weight loss intervention (STEP), where an initially low-intensity intervention is increased if weight loss milestones are not achieved at fixed time points, would result in greater weight loss compared with a standard behavioral weight loss intervention (SBWI).
Three hundred sixty-three overweight and obese adults were randomized to SBWI or STEP and were placed on a low-calorie diet, prescribed increases in physical activity, and attended group counseling sessions ranging from weekly to monthly during an 18-month period.
"Among overweight and obese adults, the use of SBWI resulted in a greater mean weight loss than STEP over 18 months," the authors wrote. "STEP resulted in clinically meaningful weight loss that cost less to implement than SBWI. Whether this weight loss results in improved health-related outcomes warrants further investigation."
The second study, "Effects of Dietary Composition on Energy Expenditure During Weight-Loss Maintenance," looked at the effect on energy expenditure and components of the metabolic syndrome of three types of commonly consumed diets following weight loss and found that decreases in resting energy expenditure and total energy expenditure were greatest with a low-fat diet, intermediate with a low-glycemic index diet and least with a very low-carbohydrate diet. Study authors said the preliminary results, which included 21 overweight and obese young adults, suggest a low-fat diet may increase the risk for weight regain compared to the other diets.
After achieving 10 percent to 15 percent weight loss while consuming a run-in diet, participants consumed the following three diets in random order, each for four weeks:
- Isocaloric low-fat diet (60 percent of energy from carbohydrate, 20 percent from fat, 20 percent from protein; high glycemic load)
- Low-glycemic index diet (40 percent from carbohydrate, 40 percent from fat, and 20 percent from protein; moderate glycemic load)
- Very low-carbohydrate diet (10 percent from carbohydrate, 60 percent from fat, and 30 percent from protein; low glycemic load)
The researchers found that energy expenditure during weight-loss maintenance differed significantly among the three diets.
"These findings suggest that a strategy to reduce glycemic load rather than dietary fat may be advantageous for weight-loss maintenance and cardiovascular disease prevention," the authors wrote. "Ultimately, successful weight-loss maintenance will require behavioral and environmental interventions to facilitate long-term dietary adherence. But such interventions will be most effective if they promote a dietary pattern that ameliorates the adverse biological changes accompanying weight loss."
In an accompanying editorial, George A. Bray, MD, of the Pennington Biomedical Research Center in Baton Rouge, La., said both studies "provide valuable information for clinicians who treat obese patients."
However, he pointed specifically to the first study, and said that despite the successes of the approaches, "the findings do not answer the question of how to achieve weight loss in a manner that will be appealing enough to the participants to result in long-term, sustained weight loss."
Overall, "it may be possible to have a more individualized approach to weight loss, rather than a one-size-fits-all approach," noted Bray. But "the most efficient treatment approach incorporates periodic reassessments and adjustment of the weight loss regimen based on a patient's success at any given time."