Calories In, Calories Out: Still Useful in Choosing a Weight-Loss Plan

Previous studies of various diets with different macronutrient compositions (e.g., low-fat, low-carbohydrate) have shown little difference in promoting weight loss. Now, the same has been shown for major brand-name diets. Researchers conducted a meta-analysis of 48 randomized, controlled trials in which well-known diets were compared with no diet or alternative diets; analysis involved about 7300 adults (median age, 46; median body-mass index, 34 kg/m²; mostly healthy, other than obesity). The diet types studied were low-carbohydrate (e.g., Atkins, Zone), low-fat (e.g., Ornish), and moderate macronutrient distribution (e.g., Jenny Craig, Nutrisystem, Weight Watchers).

All diets were better than no diet at 6 months and 12 months, and weight l…