Thermogenesis: Why Eating Protein on Dukan Diet Burns Fat
It used to be thought that a calorie is a calorie, in terms of the effect that they have on our body weight, meaning that if you ate 100 calories of protein, 100 calories of fat or 100 calories of carbohydrate their impact would be the same. This is no longer the case and it is now considered that all calories are not equal, but this needs a little more explanation as a calorie is a measure of the energy that our food supplies and a calorie is the unit of energy it takes to raise the temperature of 1 gram of water by 1 degree Celsius.
It would therefore seem totally logical to assume that 100 calories of any type of food will provide the same amount of energy and this is correct, but 100 calories of different types of foods provide different net increase in energy. This is because to extract the energy our bodies have to process the food and it does not take the same amount of energy to process 100 calories of fat as it does to process 100 calories of protein.
One of the best analogies I can think of, is to think of our body as an engine which can run on three different types of fuel, protein, fat and carbohydrate, but the engine is tuned to run most efficiently, on fat, then carbohydrate and finally protein. Therefore if you put a gallon of fat in the engine you will get more miles per gallon than you would from a gallon of protein.
There are a couple of terms used to describe this process, one is Specific Dynamic Action (SDA) and this is the term that Dr Dukan uses in his book, whilst the other is Thermogenesis. Dr Dukan advises in the UK Version of The Dukan Diet that the SDA of carbohydrates is 7%, the SDA of fats (lipids) is 12% and the SDA of protein is 30%. I haven’t been able to find the scientific data on which Dr Dukan based the information he provided. I did find an article Diet Induced Thermogenesis (DIT) published in Nutrition and Metabolism in August 2004. This article advised:
…. DIT is different for each nutrient. Reported DIT values for separate nutrients are 0 to 3% for fat, 5 to 10% for carbohydrate, 20 to 30% for protein , and 10 to 30% for alcohol. In healthy subjects with a mixed diet, DIT represents about 10% of the total amount of energy ingested over 24 h. When a subject is in energy balance, where intake equals expenditure, DIT is 10% of daily energy expenditure.”
While the information does not exactly match that provided by Dr Dukan it does confirm that protein has the highest SDA or DIT of all the food types. This means that by switching the balance of the food types you eat, to foods which are low in fat and high in protein, your body will obtain less net calories than it did before where the number of calories consumed remains the same.
I’ll illustrate this using some simple figures. Imagine that you have a normal diet of 2,500 calories with 10% DIT this means that the net calories you obtain from your food each day is 2,250. You then start to follow the Dukan Diet and increase your overall DIT to say 20% by eating less fat and carbohydrate and more protein but continue to eat 2,500 calories however the net calories you obtain from your food has dropped by a further 250 calories to just 2,000.
So this is why eating protein on the Dukan Diet burns fat.