High-quality protein is the most important food for losing belly fat.
The most consistent indicator of leanness around the waist is a high-quality protein intake, which is defined as foods that contain a “threshold” amount of 10 grams of essential amino acids (EAAs).
For example, a large study of young volunteers found that those who ate the 10-gram “threshold” dose of EAAs at every meal had the least belly fat, and the number of times they reached the EAA threshold was also significant.
How to use it: Eat animal-derived protein—beef, fish, poultry, milk, and eggs—at every meal. You get more bang for your calorie buck by eating these foods.
Use lower quality protein sources, such beans, lentils, and some vegetables as sides and condiments. There are many benefits to plant proteins, but if you get most of your protein from lower quality sources you have to eat more calories to get the same overall EAA intake.
Loenneke, J., Wilson, J., et al. Quality of Protein Intake is Inversely Related with Abdominal Fat. Nutrition and Metabolism. 2012. 9(5).