For years, medical advice and diets have been thrown at us in relation to "calorie control" and for years, people have had great difficulty losing weight with these kinds of diet. A great deal of hardship has been gone through to lose relatively small amounts of weight. Considering it recently I've come to the conclusion that calories are a bit of a con and that's why calorie control does not work.
Q: How do they measure calories in food?
A: They set fire to it.
They set fire to it and measure the heat generated during burning. This may well be where the phrase "burning calories" comes from in relation to exercise. The body on the other hand does not set fire to anything. What the body does is turn food into energy in the form of glucose or store it in the form of fat. This is a completely different process from simply setting fire to it.
So for carbohydrates in particular, the body converts the carbs to glucose quite easily. If there is too much glucose for the body's needs it is stored in the liver as glycogen and once that is at capacity, its converted to fat and stored.
When it comes to fat and protein, the body can also convert these directly to glucose, but its not as simple a process. It takes longer and is much less efficient than producing glucose from carbohydrate. To put it another way, in order to make glucose out of fat, the body has to burn energy. So one calorie's worth of glucose is easier to produce from carbs than from fat.
So not all calories are equal. If you eat 100 calories worth of carbs instead of 100 calories worth of fat then it will generate more glucose - which has to be either used or stored.
Looking at protein, this is mostly amino acids which are required for essential processes and building in the body. While its possible to "burn" protein, the body will always need amino acids. So protein is not burned unless there is a shortage of carbs and/or an excess of protein.
So if protein is not burned and generates no calories, then you may be able to discount all the calories from protein, no matter how many calories it emits when you set fire to it. Fat "costs" calories to "burn" so the calories from fat are worth less than calories from carbs.
So what do all the calorie controlled diets recommend you eat? Carbs. They are focussed on fat avoidance because gram for gram there are more calories in fat. This usually means avoiding a lot of protein as well since the two go hand in hand a lot of the time.
So you eat more carbs than you did when you started out. So more gets converted to glucose. So you have more free glucose to use as energy. So you don't use glucose stored as glycogen or fat. So you don't lose much weight.
At best calories are highly misleading simply because they are measured by a process which has nothing to do with how the body uses food. When people start counting calories they focus on foods which are lower in calories, avoid the fats and end up eating more usable calories.
So do calories have any use at all? Only really if you are eating the same proportion of foods all the time because otherwise you change the availability of energy from those foods and the calorie count becomes meaningless.
Calorie counting basically drives people to eat more carbs, which is bad enough but in diabetics its positively dangerous.
Oh and it will make you fat ;)
