The Flat Belly Diet says you'll lose inches and pounds if you add MUFAs to every meal.
That's short for foods high in monounsaturated fatty acids.
"They can have a heart healthy benefit by keeping our arteries nice and clean," said Ruth Pupo, a registered dietitian.
Pupo says studies show MUFAs lower bad LDL cholesterol levels and can also help alter your metabolic rate.
So, eating a MUFA at breakfast could boost your calorie burn for up to five hours.
What are the five belly busting MUFAs?
- Oils, like canola, olive and safflower
- nuts and seeds
- Olives, black or green
- Chocolate dark or semisweet
But there's a catch, the diet limits your daily calories to 1600 and suggests you eat four to five times a day. So does it work?
"When we eat healthy fats we tend to feel fuller for a longer period of time and that decreases our appetite," said Pupo.
Pupo warns against following any diet that's too restrictive. She says 40 to 70 percent of dieters will regain the weight within twelve months if they don't make lifestyle changes, like adding exercise to their routine.
"There's no magical food that will actually spot reduce on our body unfortunately. We need to overall reduce choleric intake and increase our exercise. We need to live a healthy lifestyle to get the desires that we want," said Pupo.