The concept goes something like this: some veggies are so low in calories that they require more energy to digest than they contain. The result? Eating celery, cucumbers or iceberg lettuce can give you a “negative calorie balance.” Sounds great in theory, but “the calories you need for digestion won’t ever exceed the number of calories any type of food contains,” says Los Angeles-based nutritionist LeeAnn Smith Weintraub, RD. However, these non-starchy, low-calorie veggies can still help you lose weight since their fiber and water content will keep you feeling full for longer. So go ahead and pile them on generously when you hit the salad bar for lunch. " copyright="iStock" attribution="" fullImage="/yahoohealth/gallery_assist/62/gallery_assist3465/calorie-burning-myths-celery.jpg" page="1 of 8" collectionName="ArticleItems"/> Celery, cucumbers and iceberg lettuce have negative caloIt sounds like it makes sense: Your body needs energy for a morning run, so not eating beforehand forces your body to dip into its fat stores for fuel, allowing you to burn more fat. Exercise physiologist Brad Schoenfeld, CSCS, author of Women’s Home Workout Bible, spent years researching the theory, hoping to confirm it as fact.