For middle-aged people with extra weight, cutting carbs a lot might burn more belly fat — especially the dangerous kind around organs — even if you lose the same total weight as someone on a low-fat diet.

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.

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 middle-aged and your body doesn't respond well to insulin, cutting carbs and eating more fat might help you lose belly fat better than a low-fat diet. But if your body handles insulin normally, both diets work about the same for fat loss.

Eating very few carbs and more fats for 12 weeks makes the dangerous belly fat around organs shrink by about a quarter in people who have too much body fat.

If you're a middle-aged adult with extra weight, eating either a low-carb high-fat diet or a low-fat diet with fewer calories can help you keep your muscle while losing weight over about 4 months.