FlipFact of the Day: The snack of choice for fitness enthusiasts and dieting gurus everywhere, celery is perhaps the most popular example of a “negative-calorie” food—a food that supposedly has fewer calories than the amount you burn when you’re eating it. Admittedly, that does sound a bit too good to be true, and one can’t be faulted for asking if calorically negative foods really do exist. Unfortunately, the fact that we’re even discussing this here should already clue you in that the answer is “Negative.” At least, according to science.
For a certain type of food to be truly “negative-calorie,” its thermic effect (defined as as the percentage of its energy content necessary to digest it and process its nutrients) should exceed 100 percent. In the case of celery, we use up only about 8 percent of its caloric content to digest it. Other supposedly “negative-calorie” foods, such as grapefruit, broccoli, apple, and cabbage, also don’t have a thermic effect that surpasses 100 percent. Basically, they aren’t calorically negative because you still do gain calories from eating them (albeit in small amounts).
Now, you might be thinking: “What if I just chew my food really slowly, so that I’ll expend more energy?” Well, consider this: A stick of chewing gum has about 11 calories, and a study showed that you’d have to chew it for an 𝘩𝘰𝘶𝘳 just to burn that amount of energy.
However, these foods certainly can (and likely will) help you lose weight. Aside from the fact that they’re low in calories, celery and other fiber-rich foods will keep you fuller for much longer. So while shoving stick after stick of the green stuff in your face won’t magically make you lose weight, substituting your favorite potato chips with celery would definitely help your #BalikAlindog plans. Just make sure to skip the cream cheese dip.
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Author: Mikael Angelo Francisco
Bitten by the science writing bug, Mikael has years of writing and editorial experience under his belt. As the editor-in-chief of FlipScience, Mikael has sworn to help make science more fun and interesting for geeky readers and casual audiences alike.