When it comes to weight loss, there seems to be a common belief that if you eat fewer calories than you burn you will lose weight. Part of this notion is that a calorie is a calorie so if you eat 200 calories of fat or 200 calories of carbs, the consequence on the body is the same. Over time I have found this to be false – a calorie of fat will have different consequence on the body than a calorie of carbs or a calorie of protein. Further more, not all carbs are the same – watch the link.
People need to stop saying that changing body composition is about energy in and energy out because it isn’t the case. It is about the amount of specific energy in. For example, low carb, high protein and fat diets are more efficient at reducing body fat when compared to low fat diets even when calories and activity level are the same.
Fat loss is possible but only if you eat the right foods in the right amounts for a sustained period of time. With the exception of high intensity athletes, most people will get better fat loss if they limit their sugar intake (of ALL types of sugar and particularly fructose and man-made sugars like high fructose corn syrup).