negative caloric effect

 Certain foods have a negative caloric effect, meaning they burn more calories during the digestive process than they contribute?  

Turns out the negative calorie theory is a myth. But that doesn’t mean some foods aren't incredibly low-calorie and super-nutritious. .

For any people, metabolism does slow over time. We know that because we can measure it. Arriving at our laboratory early in the morning, we fitted each participant with a special device that sampled the air she inhaled and exhaled. With some simple calculations that told us her calorie-burning speed.

Once her metabolism was measured, each participant then ate breakfast. Immediately, her metabolism picked up. As she absorbed the nutrients from the foods she ate, her metabolism rose and stayed higher than it had been for several hours. That’s normal.

But then, each participant began a low-fat plant-based diet. No meat, no dairy, no eggs, and keeping oils to a minimum. Fourteen weeks later, the participants came back to the laboratory and had their metabolisms measured again. And we found that the average after-meal metabolism was now 16 percent higher than before. That might not sound like much. But if you get that extra boost three times a day, the calorie burning adds up. In other words, a low-fat plant-based gives you a weight-control edge.

You can think of this as a “negative-calorie effect.” It does not mean that foods have no calories, or less than zero calories. Rather, it is a “calorie-subtracting” effect. The foods you eat have calories and healthful nutrients, and some of those calories power your body, while others are simply lost as body heat.