Although no foods actually have a negative calorie value, the premise of the negative calorie diet is that some foods burn more calories to chew and digest than they contain. No science supports this theory, explains the Every Diet website, but filling up on low-calorie food in place of high-calorie items can indeed lead to weight loss. If you don't want your entire diet to consist of negative calorie foods, you can swap in some of these foods in recipes. For instance, add chunks of vegetables in place of meatballs in spaghetti sauce.
Numerous vegetables qualify for the negative calorie diet. Include cruciferous vegetables such as broccoli, cabbage and cauliflower. Some root vegetables are acceptable, including beets, carrots and turnips. You also may eat asparagus, bell peppers, celery, cucumbers, endive, green beans, various types of lettuce, onions, radishes, spinach, watercress and zucchini. Although you may think of garlic as a spice, it's actually a vegetable in the onion family. Add garlic cloves to meals for extra flavor.
Eat large amounts of fruit during a negative-calorie diet, advises Fat Free Kitchen. Include apples, grapefruit, lemons, limes, mangoes, oranges, papaya, peaches, pineapple and tangerines. If you like melons, include cantaloupe, honeydew and watermelon. Enjoy blueberries, cranberries, raspberries and strawberries as well. People tend to view the tomato as a vegetable, but technically it's a fruit--and it also qualifies for the negative calorie diet.
Hot peppers such as cayenne, jalapenos, habaneros, serrano and other chili peppers can burn calories by speeding up your heart rate and metabolism, according to FitFAQ.com. If you like spicy food, keep a variety of peppers on hand and add chopped peppers to your meals.
Black tea, green tea, yerba mate and coffee all contain caffeine that can boost metabolism and help you burn more calories, according to FitFAQ.com. In addition, green tea, black tea and yerba mate contain epigallocatechin gallate, a polyphenol chemical compound that has the same effect. These beverages also contain no or nearly no calories. For more beverages with very low calorie levels, try herbal tea or add a splash of fruit juice to seltzer water for a soda-like treat.