Negative-calorie foods. I first stumbled across this notion on Pinterest. I, personally, am obsessed with Pinterest. But it is important to remember that this is not a great source of reliable information (much like Wikipedia).
The idea behind negative-calorie foods is that the energy it takes to digest and absorb that food is more than the calories that food contains. Below is a sample list of these foods.
However, this school of thought is not accurate. These are, in fact, very low calorie foods. And, we do burn calories during the digestive process (this is called the thermic effect of food). But, the thermic effect of food is only estimated to be 10% of our energy intake. So, a cup of asparagus is approximately 180 calories and the thermic effect of digesting the asparagus would be around 18 calories. This is no where close to negating the calories of the asparagus. Different food groups do have different thermic effects:
So, at most, we burn off 30% of the calories of some foods during digestion. But we never burn off 100% or more of the calorie content of that food. If negative-calorie foods actually did exist, don’t you think that’s all people would eat? And don’t you think you would have heard of it by now?