Dr Donald Hensrud from the Mayo Clinic breaks it down: “Foods that contain few calories, such as celery and other non-starchy vegetables, provide a small number of calories but still require energy to digest,” he says. “That means it is theoretically possible to have a negative-calorie food.”
He does add, however, that here are no reputable scientific studies to prove the theory actually works. “[But] even if non-starchy vegetables are not negative-calorie, they are still low-calorie, and a smart choice to include in a predominantly plant-based diet,” he says.
Of course, no-one’s advocating you eat only the foods on this list – that would be plain crazy. But if you were looking for an added incentive to eat more fruit and veggies, this is it.
The 20 ‘zero calorie’ foods
11. Green beans