Exercising on Empty Stomach – The Key To Weight Loss

“You need food to fuel your workouts” – One of the greatest misconceptions about weight loss exercising

This thesis has been called into question lately – Indeed, consuming carbs before working out can increase performance (mostly in sprinting & sports that require power), but it also stops the body from using the already stored body fat for energy, thus stopping the weight loss process. So, if you exercise to stay fit and/or lose weight, exercising on empty stomach is the more effective option.

Fasted State

After you have a meal, your body is in fed state. It releases insulin to lower blood sugar, glucose is transported to the muscles for energy and the fats & proteins are absorbed by the digestive system. This state lasts about four to six hours after you’ve had your meal.

Six hours after your last meal, the body enters the fasted state. Glucagon is released to keep the blood sugar at normal levels. The fat (adipose) tissue starts breaking down into free fatty acids that convert into a form of energy known as ketone bodies. Basically, you are burning fat for energy when exercising on empty stomach.

Studies demonstrate that a bout of aerobic exercise on empty stomach, compared to exercising on heavy carb diet increases the reliance on fat and subsequently reduces the reliance on carbohydrate as fuel during exercise, with several publications showing that fasted exercise burns around 20-30% more fat.


The theory behind fasted exercise is strong, but it is not easy to switch from working out on a heavy carb diet to fasted exercise. Experts suggest starting your fasted training with aerobic activities, like walking, jogging or cycling. In the beginning, the workouts will feel a lot harder, but in short period of time, the body will get used to it and will start burning fat for fueling your workouts.

Completely stay off carbs?

Although exercising on empty stomach will help you lose weight, it is not recommended to completely avoid carbs. Ultimately, the goal should be ‘metabolic flexibility’ – that is, to prime the body to use both carbs and fat as and when required. Two energy stores are better than one.

Advice: Always drink water, before, during and after workout. It is essential to stay hydrated, especially during workout, since you are losing a lot of water through sweat. The general guidelines are to drink 17 to 20 ounces of water 2 to 3 hours before exercising, another 8 ounces during your warm-up (or 20 to 30 minutes before exercising), 7 to 10 ounces every 10 to 20 minutes during exercise, and 8 ounces of water within 30 minutes after exercising.