Carbohydrates or “carbs”, as most people refer to them these days, are the number one enemy to fat burning in most people’s diets. Although it might appear to be more logical to reduce the intake of fat when trying to lose fat, the hormonal effects of high carb intake will completely block the body’s ability to burn fat.
Carbohydrate intake blocks the body’s ability to burn fat because it triggers the production of the hormone insulin. Most people associate insulin with the disease diabetes and with blood sugar control, but it is also directly involved in the storage of fat in the body. Insulin stimulates the tissues to convert excess blood sugar and store as fat, and at the same time will block the conversion of fat back to sugar so it cannot be burned for energy.
When you eat a lot of carbs, they are quickly digested and absorbed into the blood as blood sugar, also known as glucose. A rise in blood glucose above what the body needs for its immediate energy needs triggers the release of insulin from the pancreas. Insulin stimulates the muscles and liver to store the excess glucose as a compound called glycogen, which is a quick energy source. The amount of storage space available for glycogen is pretty limited, and when that is filled up, the insulin stimulates the fat tissue to store the remaining excess glucose as fat. This means the more carbs you eat, the more insulin you will produce, and the more fat your body will store.
Some people think that they can overcome this problem by simply exercising more to make up for eating too many carbs, but this will not work. Even though exercising more will burn additional calories, they won’t be fat calories!
Exercise does stimulate the body to first burn glycogen, and then turn to burning fat once the glycogen is used up - except when there is high insulin release. In the presence of high insulin, once the glycogen is gone, the insulin blocks the burning of fat and so the body turns to burning the protein of your muscles to produce energy.
At first, people who are trying to lose weight and continue to eat a lot of carbs may have the illusion that they are burning fat, but in actuality, they are losing water weight and muscle mass. As this goes on longer, the loss of muscle results in a lower metabolic rate, which makes it even harder to lose weight. The end result for the person who continues to eat a lot of carbs while trying to lose weight is that they wind up feeling up weak and tired and have an even higher percentage of body fat than before they began their weight loss program.
