Should you work out on an empty stomach?

Do you want to work out on an empty stomach, or do you need the advantage of getting some fuel in the tank to help propel you through an exercise morning? If your goal is to burn fat or create muscle mass, here’s what scientists found when they studied the effect on our exercise habits of the timing of our food choices.

While more studies are needed, scientists recently came to some conclusions about one important question: whether it makes more sense to eat before or after your sweat session.

In a 2017 study published in the American Journal of Physiology: Endocrinology and Metabolism, UK researchers had a group of overweight males walk on an empty stomach for one hour at 60 percent maximum oxygen consumption; then, on another day, after consuming a high-kilojoule, high-carbohydrate meal, they had them walk again for two hours. After eating and while fasting, as well as after exercise, the researchers obtained numerous blood samples. Before and after one hour of walking, they also took adipose tissue (fat) samples directly.

The results showed differences in gene expression of the fat tissue in the two trials. The two genes they looked at, PDK4 and HSL, increased as a result of the volunteers fasting and exercising and decreased when they ate before exercising.

The researchers conclude that the rise in PDK4 possibly suggests that stored fat was used during exercise to fuel metabolism as opposed to food carbohydrates and that HSL increased when energy was stored by the fat tissue to benefit from a boost in exercise. In short: when volunteers exercised without a pre-workout snack, instead of fuel from food, they burned off body fat.

The type of exercise you’re doing will help decide whether before your workout you should eat. You do not need to fuel up beforehand for light or low impact workouts, such as cycling, golfing, or gentle yoga. However, before exercise, you should always feed, which takes a lot of muscle, energy, and stamina. Tennis, hiking, and swimming are part of this. If you intend to work out for more than an hour, it’s particularly necessary.

There are certain times you may want to eat during strenuous exercise lasting more than an hour, such as during a marathon. This is necessary to maintain blood glucose levels needed to continue moving. It also helps you avoid using up stored energy in your muscles, which can help you build muscle mass.

Do not sweat it if you work out on an empty stomach at times, but for strenuous or long-lasting workouts it might not be safest. You’re the best guide for yourself, so listen to your body and do what feels good for you. Keep hydrated properly, maintain a healthy diet, and live a lifestyle in accordance with your best interests in fitness. And before beginning any new fitness program, remember to speak with your doctor.

Check out my related post: Do you know about your body’s metabolism?

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One comment

  1. Thank you for your insightful post. I have been working out on an empty stomach for over a year now. I do strength training and Hiit workouts. I have found that I have more energy and get a better workout on an empty stomach. Take care. Scott


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