Can you loose weight by eating pineapple?

Is it just hype or are there really negative calorie foods? For as long as I can remember, I heard that you burned more calories chewing pineapple than you actually got by eating it. Is this true? I decided to find out.

My research took me to The Food Lover's Companion and On Food and Cooking (where else?) Neither had anything on negative calories in regards to the pineapple, I did learn however, that the pineapple must be picked ripe or the starch will not convert to sugar. Hmmm...

Apparently, the theory that you can burn calories by eating certain foods was the basis of the 1990s book Foods that Cause You to Lose Weight: the Negative Calorie Effect and includes other foods such as asparagus, lettuce, broccoli, beets, onions, cabbage, carrots, cucumber, zucchini, apples, oranges, pineapple, grapefruit, raspberries, pineapple, strawberries, lemons and limes.

So, can you eat your way to losing more weight? I couldn't find any scientific proof to prove this theory but stumbled across some great web articles:

My Diet Power

Excerpt:

"Calories are expended in three ways, Eckel explained: 70 percent through basal metabolic rate (basic activities of living), 25 percent through exercise, and 5 percent through thermogenesis (the cost of absorbing and storing calories). "Typically, a five-calorie carrot would need about 0.25 calories to absorb and store," says Eckel. "Thus, the carrot still has about 4.75 calories. The only way one burns more than one eats is if you eat less or exercise more. A calorie never changes."

Barbara Rolls, Ph.D., professor of nutritional sciences at Pennsylvania State University, finds the theory of negative-calorie foods "interesting, but very hypothetical. I don't think we have the metabolic tools to determine whether this is possible." Rolls thinks people lose weight eating so-called negative-calorie foods not because the foods burn calories, but because they displace higher-calorie foods. Co-author of the book Volumetrics: Feel Full on Fewer Calories, Rolls says that "clinical trials show that eating high-water-content fruits and vegetables helps with weight management."

"You eat fewer calories through satiety," Rolls concludes, "not through the metabolic effect."

Negative Calorie Foods: This article talks about fat burning foods.

Excerpt:

"Fat-burning fish foods: Salmon, Tuna, and Sardines. These foods all contain large amounts of omega-3 fatty acids which, besides being incredibly healthy, seems to have a strong effect on metabolism. Omega-3 fats (the healthiest of 'good fats') alters levels of a body hormone called leptin which directly influences metabolism and determines whether you burn calories or store them as fat. Basically, the less leptin you have in your bloodstream the more calories you use for energy. Cold-water fish and omega-3 oils like flax seed oil - which is definitely a strong fat-burning food - have been shown to significantly lower leptin levels and improve metabolism."

And for fun: "Caffeine and EGCG have both been shown to help you work out harder and longer!"