In the past, intermittent fasting was not a choice due to scarcity of food. People would go hours or days without eating. Today, we have access to food whenever we want. This shift in eating habits has led to questions about the benefits of fasting and its potential reintroduction.

Intermittent fasting usually involves limiting food intake to specific times or days, like eating only for eight hours out of 24 (16:8 diet) or restricting calories for two days out of seven (5:2 diet).

Strong Points

Intermittent fasting can help with weight loss, particularly fat loss, as it reduces overall caloric intake. It also provides structure to eating days and can be flexible and intuitive. Some benefits include decreased hunger, lower levels of the hunger hormone ghrelin, reduced appetite, and improved fat burning.

Fasting may also lower the risk of type 2 diabetes and improve vascular health. Research shows that intermittent fasting is beneficial for cardiometabolic health and may have positive effects on long-term cardiovascular health.

There is evidence to suggest that fasting can protect against issues related to aging, improve autophagy, and potentially benefit brain health and cancer risk, but more research is needed to support these claims.

Cons

Concerns about fasting include potential muscle loss and the lack of long-term studies to support its safety. Some studies suggest that restricting eating to less than eight hours a day could increase the risk of death from cardiovascular disease, but data collection methods and sample sizes in these studies may be flawed.

There is also a risk of reduced protein intake with intermittent fasting, which could be problematic for some individuals, especially those with a history of eating disorders or health conditions that require regular meals.

Experts recommend ensuring adequate protein intake and incorporating strength training if trying intermittent fasting. It’s important to approach fasting like any other diet, not as a permanent solution, and to pay attention to food choices when breaking the fast.

About our experts

Dr. Jason Fung, Dr. Darryl Gioffre, Brady Holmer, and Drew Price are experts in their fields and have published work related to intermittent fasting, nutrition, and health.