When overweight people eat fewer calories and get regular coaching, it doesn’t matter much if their diet is high in fat, protein, or carbs—they lose about the same amount of weight no matter what.

If you're overweight and eat fewer carbs instead of less fat for four weeks, you might lose more body fat—even if you lose the same amount of total weight as someone on a low-fat diet.

If you're overweight and eat fewer carbs instead of less fat for four weeks—without counting calories—you might lose about 8 pounds more than someone on a low-fat diet, and it might be because you're losing more body fat.

If you're overweight and eat less fat for four weeks, you might lose more muscle than fat compared to someone who eats fewer carbs — even if both diets help you lose weight.

Eating fewer carbs and more fat—without counting calories—can help people lose about as much weight as eating less fat and cutting calories. This suggests that what you eat might matter just as much as how much you eat.

The more often overweight people attend weight-loss counseling sessions, the more weight they lose—even if they’re on different diets—suggesting support matters more than what you eat.