Exercising on an empty stomach

Exercising on an empty stomach (“fasting cardio”) may help burn more fat 

Fitness, ,

Recent research from the University of Bath (England) showed that exercising on an empty stomach results in more fat loss than exercising after eating. “Fasting cardio” may be something you try if you have difficulty losing body fat by other means. 

“Fasting cardio” may be familiar to those who know something about “intermittent fasting”, which research shows gives multiple health benefits. Fasting cardio specifically means doing aerobic exercise (usually in the morning), without having had breakfast before.

Fasting cardio makes sense

Thinking about metabolism, fasting cardio makes sense. If you eat before exercise, you mostly burn calories from the glucose you get from the food you recently ate. If you are fasting, you will be more likely to burn calories from your stored tat and sugars.

The British exercise study

This study, published in The Journal of Clinical Endocrinology & Metabolism, involved 30 sedentary overweight men. They were randomly split into 3 groups of 10 men each. The first group (called the control group), did nothing different during the six-week study. They carried on their normal life.

The other two groups were put through an exercise routine over the next 6 weeks. Each of these men in the 2 groups did a morning exercise program on a stationary bike, at a moderate pace. During exercise, they were monitored with heart monitors and face masks to measure how much fat and sugar they burned during their exercise.

One of the exercise groups drank a vanilla flavored shake (with plenty of calories) 2 hours before their exercise. After exercise, they drank a flavored drink which was basically water and no calories.  The third group of men drank this calorie-free beverage 2 hours before their exercise, and after the exercise, they drank the shake with calories.

The results

After 6 weeks, all the men who exercised were in better physical condition, but the men who exercised after drinking only flavored water (fasting cardio) lost almost 50% more fat calories than the men who drank the calorie-rich drink before exercise. Both groups burned about the same number of calories, but the fasting cardio group lost more of their calories from fat.

Some previous studies— similar to this study—have shown the same results, but some other studies showed that it didn’t matter if you ate before or after exercise. This English study though was particularly well carried out (blind and randomized), so we should consider these results with some confidence.

What this means

If you have been exercising after eating, you might try fasting cardio to see if, over some weeks, you get better results. If you exercise in the morning, just do not eat before that, but if you prefer to exercise at night, try not eating for 4 or more hours before your exercise. In either situation, remember that you should keep hydrated, so drink as much water as you need. 

Some cautions

You should be in good health to undertake any fasting program, including fasting cardio. If your exercise requires quick power (such as sprinting or tennis), you are better off eating before. A fasting cardio workout should not be longer than 60 minutes, and of low to moderate intensity. While most people do not notice any problem working out on an empty stomach, if you get dizzy or just don’t feel right, don’t do it. Any exercise is good, but listen to your body.

To find a doctor, of any specialty, anywhere in Brazil, check out our website: www.ProcuraMed.com.

See also in ProcuraMed:

How intermittent fasting can improve health

How to experience intermittent fasting for yourself

Esta postagem também está disponível em: Portuguese (Brazil)

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