Low calorie diets are not in right now, but they will be again. It is my contention that one should not toss around terms like “carbs” and “protein” and “calories” without really knowing what they are. That they are something in food which makes you gain weight is the generic understanding people have. Diet soda is good because it does not have any. Things that taste good probably have a lot of them.
Calorie is short for kilocalorie, the unit of energy required to raise 1 kilogram of water 1 degree Celsius. A piece of food with 100 Calories (properly capitalized to identify it as a food calorie, or kilocalorie, equal to 1000 small non-food calories) would yield 100 Calories when combusted, and could thus raise 1 kilogram of water 100 degrees Celsius. In short, Calories describe how much energy a substance contains. Protein and carbohydrates each contain 4 Calories per gram, and fat contains 9 Calories per gram. That means fat contains more than twice as many Calories per equivalent mass. In theory, eating less Calories means less weight.
But this is only in theory. The basic discussion in popular nutrition is that one has to burn off more Calories than one takes in to create weight loss. This is true, but there is a larger discussion both in Chinese medicine and in professional nutritional medicine as well, of metabolism. You need energy to fuel it. If you repeatedly take in too little of it, you deplete your reserves (see The Kidneys Store the Jing), weaken your metabolism, and gain more weight. Calorie utilization depends both on individual metabolism as well as the food the Calories are contained in. Poor quality, low nutrient foods will produce greater weight gain than an equivalent caloric serving of high quality, high nutrient foods. This is partially because the body can utilize the nutrients to fuel its metabolism, thereby reducing the negative impact of caloric accumulation as fat or as other forms of long term energy storage. Because there is little to be done with the poor quality foods, Calories are simply stored.
If you learn to eat well, you will never have to count Calories. You will also never have to think about “carbs”, or “net carbs”, or “bad carbs”, or getting enough protein. And, best of all, you will be freed from a lifetime of struggle and obsession with food.