

Answers from Francisco Lopez-Jimenez, M.D.

Maybe. Researchers aren't sure why, but it seems that regularly fasting — severely restricting food and drink for a 24-hour period on one to two days a week — can potentially improve your risk factors related to heart health.

It's difficult to tell what effect fasting has on your heart health because many people who routinely fast often do so for health or religious reasons. These people generally tend to not smoke, which also can reduce heart disease risk.



However there are concerns about the potential side effects of regular fasting for certain people or in specific circumstances.

  • People with eating disorders may end up binge eating more after fasting.
  • Fasting and exercising at the same time may lead to low blood sugar (hypoglycemia), which can cause dizziness, confusion and lightheadedness.
  • Fasting by people taking diabetes medications can lead to severe hypoglycemia and can lead to serious health issues.
  • Skipping breakfast may be considered fasting by some because it can result several hours without food, but skipping breakfast can be unhealthy and has been associated with obesity.

More study is needed to determine whether regular fasting can reduce your risk of heart disease. Most scientific evidence on fasting comes from animal, not human, studies. The studies that have been done on people are mostly observational, which has the lowest level of scientific evidence.

If you're considering regular fasting, talk to your doctor about the pros and cons. Keep in mind that a heart-healthy diet and exercising regularly also can improve your heart health.


Francisco Lopez-Jimenez, M.D.

Sept. 28, 2017 See more Expert Answers