Home HEALTH No, ‘negative-calorie’ foods aren’t a real thing

No, ‘negative-calorie’ foods aren’t a real thing

IT sounds like a dieter’s dream: Foods that require more calories to digest than they actually contain. But, alas, so-called “negative-calorie” foods are likely a fantasy — according to a new study done in lizards, they don’t seem to exist. The study is one of the first to scientifically test the idea of negative-calorie foods — a popular notion among dieters that’s been promoted in forums, blogs and books alike. Some of the most cited examples of purportedly negative-calorie foods include celery, lettuce, grapefruit, cucumber and broccoli. The thinking goes that these low-calorie, highfiber foods take more energy to digest and process than they themselves contain.
In the new study — published March 24 on boric, a preprint website for biological studies that have not yet been published in a peer reviewed journal — the researchers found that even celery provided the lizards with more energy than it took to digest and process the food. On average, the lizards retained about a quarter of the calories in their all celery meals, while the rest were either used in digestion or excreted.
“Regardless of the [calories] in the food, you’re always going to be able to get something out of it,” said study senior author Stephen Secor, a professor of biological sciences at the University of Alabama. In the case of foods like celery, “it’s not going to be a lot; but the food itself always is going to provide a profit,” calorie wise.
Although the study was conducted in lizards, Secor told Live Science that if studies were done in people, “you probably would come out with something very similar” to the study’s results. “It doesn’t make sense you would run into a negative,” regarding calories, he added.
But even if these foods aren’t technically “negative calorie,” eating them could still help you lose weight. That’s because, being low in calories, they don’t put much of a dent in your daily calorie needs. You’d have to eat an awful lot of celery — nearly 30 lbs. (12.6 kg), according to the researchers’ estimates — to offset the number of calories you burn in a day overall.
What’s more, a meal of celery is “not going to sustain you for very long,” Secor said. Instead, the researchers suggest referring to these foods as “negative budget” foods, since consuming them “will favor a daily negative [calorie] budget, and hence weight loss,” they wrote in their paper l.