What are the main foods advocated by some websites as promoters of weight loss? They are: green tea, black tea, coffee, chili, calcium, extra protein, ginger, flax oil, medium chain triglycerides, fish oil, conjugated linoleic acid, fish oil, garlic, ginseng and many other herbs and spices. Although it is true that consuming these foods is not only harmless, but also health promoting. These food items may marginally enhance metabolic rate thereby accelerating your weight loss program. ---but only marginally! Because of their marginal (read insignificant) effect on fat loss, you can not fully depend on these items for fat reduction. Main thing which is objectionable about the claims that these food items promote fat loss is that they are based on studies whose validity is doubtful and hence they are unscientific. Another objectionable thing is that these claims will deviate your attention from the main focus which should primarily comprise of:
Many fat loss gurus these days have adopted this as the main theme. Some deeper explanation is necessary before understanding this claim. You see our central theme of fat loss (or gain ) is this simple law of physics: Eating more calories than expenditure will result in fat gain and spending more calories than eating will result in fat loss. But the issue of low carb and high carb diets needs to be explained in the context of nutrition and glycemic index.
If you eat more carbohydrates than nutritionally required, they will be stored as fat. Same is true for fat and protein with slight difference. The metabolic cost is the energy spent in conversion from the nutrient to glucose. The metabolic cost of carbs, fat and protein is not the same. The relative metabolic cost is higher for protein and lower for fat:
So it is clear that protein is marginally difficult to be stored as fat [but excess protein (and carbs and fat) in any case will ultimately and surely be converted into fat] than carbs than fat. Also body prefers carbs or fat as fuel than protein; but again, excess is converted and stored as fat. So the essence is: Anything in excess of requirement eventually will get converted into fat. Much importance need not be given to a particular nutrient but it should certainly be given to eating nutritionally correct amount of each of the three macronutrients---simultaneously keeping in mind that you have to reduce total calories.
Second part is glycemic index. When you consider carbs, all are not alike from fat loss point of view. Even if you eat equal calories, for example, of (a) candy or other sweet item and (b) whole wheat bread or oats, the effect on conversion to fat is different due to their different glycemic indexes (in addition to this there is no nutritional benefit due to candies).
Visit the page Importance of Glycemic Index for Fat Loss for knowing the importance of glycemic index in fat loss
If you are an adult, and your lifestyle is sedentary (very little exercise), then your daily diet should be weight in Kg X 30 calories. For example, if you weigh 70 Kg (155 lb.), then you should eat 70 X 30 = 2100 calories of which 0.8 X 70 = 56 grams should be protein. Your diet should include less than 30% calories from fat, and no trans-fat. If you do some moderate exercise, then multiply weight in Kg. by 35 instead of 30 in this example.