I found 2 articles talking about negative calorie foods.
One was on sparkpeople.com and another was in someones weight watchers blog, sorry I didn't bookmark it. So at the risk of plagerizing here they are, these are copy and pasted directly from their sources and as soon as I find them again I will give them credit for their words of wisdom:
"Negative Calorie Foods: 15 Foods That Actually Burn More Calories Than They Contain
Friday, December 7, 2007 at 1:36am by admin
By Laura Milligan
No, we’re not advocating the battle to see how few calories you can consume each day or promoting crash diets in any form or function; however, if you’re a snack-o-holic who can’t stop munching and crunching in between meals, try snacking on one of these negative calorie foods instead of gobbling down a cupcake or big bag of chips. Your body can burn more calories just by chewing and processing the snack than the food contains already. In other words, you’ll be able to keep eating throughout the day without packing on extra pounds.
*Celery: A staple on most party veggie trays, celery (without the ranch dressing) is a crispy snack that you can enjoy without worrying about taking in any calories. It is high in sugar and sodium, but still much healthier than pigging out on brownies or salty peanuts.
*Oranges: Before you leave for work in the morning, toss an orange into your bag for a mid-morning or late afternoon snack. An orange typically contains only 45 calories, so feel free to eat the whole thing!
*Strawberries: Strawberries are a popular negative calorie food because of their natural sweetness and juiciness. Sprinkle a few on your breakfast cereal to give your metabolism an extra jumpstart early in the day.
*Tangerines: A smaller, more tart version of the orange, tangerines are another negative calorie food that’s both tasty and portable. Enjoy one or two for a snack throughout the day to stimulate your taste buds without having to dig through the candy drawer.
*Grapefruit: As big as it is, grapefruit –without the extra sugar on top– is a surprisingly negative calorie food. One-half of a grapefruit only contains 36 calories but a whopping 78% of your daily value of potassium.
*Carrots: Carrots don’t just make your eyes sparkle; they also let you snack guilt-free. Snack on baby carrots instead of chips and salsa while you make dinner, or keep a bag in your office refrigerator when you feel the need to eat due to stress.
*Apricots: Indulge in nutrient-rich apricots for a sweet snack with negative calories. Your higher metabolism and thinning waistline will thank you.
*Lettuce: There’s a dirty little rumor in the magazine industry that the girls at Vogue keep lettuce in their desks to snack on when the hunger pains strike, but they can’t afford to compromise their stick thin figures. We’re guessing you’re not about to go through the day dizzy with starvation, but you can make yourself a hearty salad with lots of lettuce (and other negative calorie veggies!) once you get home. Don’t forget to take it easy on the dressing.
*Tomatoes: Chop up a tomato to give your sandwich, salad or egg whites omelet extra flavor without adding any calories.
*Cucumbers: Your salad can’t survive on lettuce alone. Cucumbers are another negative calorie food that are great for crunching on when your mouth is getting bored. Check here for tips on growing your own cucumbers.
*Watermelon: A traditional summertime treat, enjoying a watermelon is almost fun and delicious as eating candy because of its super sweet, super juicy nature. Plus, you’ll burn off all the calories crunching, digesting, and of course, spitting out the seeds.
*Cauliflower: Another party platter vegetable, raw cauliflower is naturally low in fat and of course, calories, so don’t be shy about piling up your cocktail napkin.
*Apples: An apple a day keeps the doctor away, but when eaten as a snack instead of candy bars or chips, apples will also keep the calories at bay. With only 81 calories per apple, your body also works a lot harder and longer to digest the fruit many other snack options.
*Hot Chili Peppers: Excess seasonings and dressings pile on lots of fat and calories to otherwise healthy meals. To avoid gaining weight simply because you’re a condiments junkie, experiment with more natural seasonings like hot chili peppers, which is a negative calorie food.
*Zucchini: Zucchini is a versatile, negative calorie food that can be baked, steamed, fried (not recommended), or prepared in many other ways. With just 15 calories per 100g, make zucchini your new diet staple.
Implementing negative calorie foods into your daily diet doesn’t just help you lose weight by cutting calories; it also speeds up your metabolism and introduces healthier items like fruits and vegetables into your regular food choices and favorite recipes. So no matter how you look at it, you’ll come out ahead."
"Certain vegetables like cucumbers, spinach, celery, watercress, alfalfa sprouts, beet greens, cabbage, chives, endive, lettuce, radishes, garlic, mushrooms, seaweeds, turnip greens, and water chestnuts all burn more calories digesting them than they contain. So, in theory, just eating a cucumber makes you lose weight. In reality, that isn't quite true, but these are all definitely veggies you want to eat a lot of. You can also include broccoli, cauliflower, eggplant, peppers, and tomato, but those veggies are borderline. So, if you're going to have a snack, why not cut up a cucumber and pour some vinegar over it? Zero points, and you may actually burn more than you ate. Pretty good, huh? Unfortunately you can't be sneaky and count these veggies as negative points, but that's alright."
