The Health Benefits of Fasting

People have fasted for thousands of years, and for thousands of years, people have held testament to this practice’s health benefits. And it turns out, they were on to something—the latest scientific research shows that the health benefits are real and manifold.

Fasting is the practice of not consuming food for extended periods. There are several different diets that incorporate fasting. The type of fast that is right for you depends on what fits your lifestyle best.


Regardless of the type of fasting you choose, studies have found a number of benefits to fasting, including:

Fat burn—When the body runs out of food to digest, it turns to glucose for energy. When it runs out of glucose, it starts burning fat. This leads to weight loss.

Metabolic boost—When the body has no food in it for a prolonged period, this causes the metabolic to fire up. This can also contribute to weight loss. One study showed fasting led to a 3-8 percent decrease in weight over a period of 3 to 24 weeks.

Preserve muscle—Because fasting causes growth hormone levels to increase in the blood, weight loss through fasting has been proven to preserve muscle better than diets that involve a prolonged reduction in calorie consumptiion.

Immune system—One study showed that longer periods of fasting (2-4 days) can clear out old immune cells and regenerate new ones, which strengthens the immune system. This immunity boost has been shown to help cancer patients reduce side effects during chemotherapy, when they fasted for three days prior to treatment.

Longer life—Two studies have even found evidence of improved longevity in fasting subjects at the molecular and genetic level—signs that fasting and modify your body’s gene expressions and help you life longer.


If you’re going to fast for the health benefits, it’s important to be aware of the risks, too. UK’s National Health Service has listed several, including dehydration, increased stress, disrupted sleep, headaches, and even heartburn. Some experts also correlate fasting to an increased risk for eating disorders. For these reasons, start fasting slowly and always listen to your body if you are struggling while fasting.