Posted by: Nige
on Apr 12, 2010
I've written about this before, but I can't do a series on diabetes myths without mentioning calories since they may be the biggest con and/or misconception in nutrition.
We are regularly told by health authorities, food manufacturers and the media that we need to eat a calorie controlled diet. But why?
A calorie is a measure of energy and your body uses energy not only for movement - jogging, swimming, poking the remote control, raising your pint glass etc - but for keeping your body's automatic systems going. So your brain uses energy all the time, your heart uses energy to keep pumping and so on. So yes we do need a certain amount of energy for the body to keep going. If we take in more energy than we use up, it gets stored in the form of fat and we put on weight.
So far so good. So whats the problem?
The problem is that calories in food are measured by putting a certain amount of food into a calorimeter, setting fire to it and then measuring how much energy is given off. Does your body set fire to food? Mine doesn't.
The body simply does not use energy in that way. All the parts of your body are made up of a collection of cells, which use energy in the form of glucose. Its similar to the way in which the cooker in your kitchen may use fuel in the form of electricity or gas or wood or coal. The fuel that your body runs on is glucose.
And it doesn't set fire to it.
As discussed in myth #2, the body makes most of this glucose from carbohydrates - because its easier to make it from carbohydrates than it is to make it from fat or protein. But when they set fire to food in a calorimeter, it doesnt take into account whether its burning carbohydrates, fat or protein.
Protein is used mainly by the body for building and repairing itself. Since thats what the body mainly uses it for, its unlikely to get turned into glucose. Some sources suggest that as little as 10% of the calories in protein get converted to glucose in a human on a "normal" diet. The rest is used for repair and building.
So when you set fire to a steak, all the protein in it burns and gives off energy - but thats not what the body does with protein so the number of calories from burning a steak bears no resemblance to what the body really does with it.
Its a similar story with fat. The body can make glucose out of fat, but its harder than making it out of carbohydrates. They are on safer ground here though since if the body already has enough glucose from carbohydrates, it will convert the excess glucose to fat and store it as fat. But there's still a difference.
If the body does not have all the glucose it needs from carbohydrates, it will convert fat to glucose. But this is much harder to do, so it "costs" energy to make glucose out of fat. So some of those calories get lost. Some sources suggest that as little as 30% of the calories get converted to glucose in a "normal" diet.
When looking at the classic "calorie controlled diet", people avoid fat because there's more calories worth of energy in fat when you set fire to it. These are usually foods with more protein in them as well - meat, cheese etc. But if most of the calories in protein and fat are never used for energy, then even though they have more calories in them to start with, they don't all "count".
But the calories in carbohydrates do count.
So a calorie controlled diet drives you towards a diet which has more carbohydrates in it, less fat and less protein. But you're likely to wind up eating more effective calories than before. This is bad enough for non-diabetics, but for diabetics its positively insane because more carbohydrates means higher blood glucose. Because its harder for the body to make glucose out of protein and fat, it takes longer. So your blood glucose rises slower and either your pancreas or your injected insulin (if you use it) has more of a chance to keep up.
So unless there is a furnace in your stomach and your body actually DOES set fire to food, then counting those calories is likely to lead you down entirely the wrong path and have you pushing your blood glucose much higher than it needs to be.
On the other hand if it does then you are about to become immensely rich because you will be the first species on the planet which uses energy in the same way that they measure it.
This is a series of blog entries about diabetes myths. Diabetes Myth #1 - Its all your own fault Diabetes Myths #2 - Its all about sugar
Diabetes Myth #3 - Calories Count Diabetes Myth #4 - Cures Diabetes Myth #5 - The Diabetic Diet Diabetes Myths #6 and #7 - "Diabetes is progressive" and "Pills or Insulin mean failure" Myth #8 - Glycemic Index is the answer. Now whats the question? Diabetes Myths #9 - Cholesterol Diabetes Myths #10 - HbA1c is an Average
