Lets say you are 180 pounds. Ssshhh! We won’t tell anyone your weight. Now lets say your body fat is thirty percent. This means you probably have a high BMI. Your body fat in weight terms is 54 pounds or thirty percent of your total weight. On the other hand, even a very fit person can store about 500 gms of glycogen or sugar. These statistics matter. They determine what your body uses as its primary source of energy.
If your regular diet consists of a high carbohydrate diet, your body will primarily use this for energy. The typical indicators of this is hunger pangs within a few hours of eating, a sugar high and crash, and the inability to ever skip a meal. Intermittent fasting? Forget about it. Your body will not allow you to. You can’t even really use fat that you are eating for energy. It gets shovelled into storage. You will constantly be craving carbohydrates. You may often need an afternoon nap and have highs and lows in your energy levels. You may get frequent headaches.
Research has shown that athletes who switch to a meal consisting predominantly of fat undergo something called fat adaptation. This means that your body can use fat as its primary source of energy. Up to 70-80 % of your energy needs can now be met by fat. You no longer get the sugar crash and can easily skip meals. You can also use fat in your meals directly as a source of energy instead of stored fats.
There is no real home test to measure if you are fat adapted. Measuring the ratio of oxygen you inhale to carbohydrate you exhale is one. If your ratio is close to 1, you are carbohydrate or sugar adapted. If your ratio is 0.7 you are fat adapted. People who have diabetes, eat late at night or are overweight have a ratio closer to 1. You goal should really be to make yourself fat adapted.