Catabolism and anabolism
There are foods that require more calories to get digested than theyprovide to the organism, and these food are known as the catabolic foods.Before you ask, catabolism is the metabolic process where you startoff with one complex molecule, break it up in a metabolic pathwaythat would take two blackboards to depict, and end up with simplemolecules such as (to keep it simple) carbon dioxide and water andsome energy. The opposite process, anabolism, starts with simplemolecules that are combined to give more complex molecules, whichwill be used for various purposes, like storage of energy, orbuilding of some sort of tissue, such as muscle. Anabolic processesrequire investment, that is, spending of energy.
Catabolic foods arerecommended to people who are trying to burn some calories and thuslose excess weight. Catabolic foods comprise of foods that burn morecalories to digest and negative calorie foods. The opposite, anabolicfoods also spend calories while they are digested, but end up ingiving more calories (this is something like lighting a fireplace -small fire from a match must be spent in order to get a large firefrom a log). Anabolic foods are therefor used by bodybuilders andpeople who wish to gain weight.
How they work
As told, catabolic foodsare energy-inefficient. They yield less than they take. Most foodsprovide more calories than is needed to digest them. Some provideless. Where is the catch? Digestion is process of breaking up complexmolecules found in food into more simple ones, which our body canabsorb and use, much like disassembling something made of Lego bricksso that you can construct something else with those same bricks. Ittakes some energy to break such complex molecules. In catabolicfoods, it takes up a lot of energy. And there is more. Some linkswithin the molecules give energy when they are broken. In anabolicfoods, this energy is greater than the energy required to break thelink that contains it, and the net energy balance is positive. Incatabolic foods, this energy is lesser, and the net energy balance isnegative. You have lost energy, that is, you have lost some calories,while you digested some kinds of food - catabolic foods. Theseinclude foods which boost the metabolism, and foods which stay instomach longer than other foods, thus preventing intake of other,potentially energy-rich foods.
So, what foods are these?
Fruits: blueberries,blackberries, grapefruit, lime, oranges, lemon, pineapple, plums,pears, strawberries, watermelons.
Vegetables: broccoli,celery, asparagus, carrots, Brussels sprouts, eggplant, leeks,spinach, lettuce, tomato, sweet potato, celery, pepper, parsleyleaves.
Meat: seafoods, low fatwhite meat.