When Does the Body Start Burning Fat During Fasting?


As soon as you start dieting, exercising, and especially fasting, you want to lose weight quickly. If you do not see the effects in your body immediately, you will probably start asking yourself a prevalent question that ‘When does the body start burning fat during fasting?’

Luckily, you are in the right place as we are going to answer that question in great detail with the help of proven statistical data.

The short answer to that question that you must be fasting for at least 12 hours before the body starts burning fat efficiently. In some conditions, it can take even up to 14 hours or even more, before the body initiates fat-burning. It is highly dependent on your glucose consumption and the amount of glycogen stored in your body.

In order to understand the duration of the fat-burning process, it is crucial to be familiar with the mechanism of fasting as well. Your body is in constant need of energy, even while sleeping. The primary source of this energy is the glycogen in your body. The glucose is synthesized into glycogen for energy. Foods rich in fats, proteins, and carbohydrates are the fundamental sources of glucose, for example, cheese, meat, fish, fruits, and vegetables.

In intermittent fasting, food consumption is stopped for a specific period, which means you are not providing fresh glucose to your body. Consequently, the body uses up glycogen stores for energy. Eventually, the glycogen stores are also entirely depleted within 12 to 15 hours in normal conditions.

After the glycogen, the body starts burning protein and then fat simultaneously to get the required amount of energy. According to a study by Medical Hypothesis, short fasts are suitable for people who wish to maintain muscles while losing weight during fasting. The data indicated that fasting up to 14 hours a day and exercising up to five days can help you in losing more fats than the muscles. Moreover, your diet must consist of a minimum glycaemic index and an appropriate amount of fats.

Another research by the Journal of the International Society of Sports Nutrition, states that if you wish to achieve the maximum results of fasting by burning the highest amount of fats, you should fast for at least 16 hours, along with some intense exercise, like resistance training.

As seen from the researches, the period in which your body starts burning fat is varied by numerous factors. Still, commonly, 12 to 16 hours of fasting is considered to be the optimum period of fasting. Other than focusing on the duration, you should pay attention to your diet as well and make sure the glucose is limited in your diet. It will reduce the level of glycogen stores in your body and hence the body will start burning fats immediately, instead of the usual 12 to 16 hours period. In this way, you will be able to burn maximum fats and enjoy the advantages of fasting.