Intermittent Fasting: Is it Safe?

Intermittent fasting (IF) has recently become a popular diet trend, and you may be curious if it is healthy or not. IF has many different definitions, but in general it means fasting for a certain period of the day or week. The most common type of IF entails fasting for 12-20 hours of the day and eating during the remaining 4-8 hours of the day. For example, it could mean eating only between the hours of 8am-4pm. Another type of IF involves restricting intake to 500-600 calories on two days, and eating normally for the remaining five days of the week.  You might have even done a type of IF for one day without realizing it before if you woke up late or went to sleep very early.

Scientific research on the health outcomes of IF has mostly been done in adults because it is not safe for anyone who is still growing to restrict their intake or follow a diet. The research that has been done in adults shows no clear health benefits in the short-term time period, and no long-term benefits at all. In fact, IF is not very sustainable and may even be harmful in the long-term.

When deciding if it safe for you to try IF (or any diet), it is helpful to take a step back and think about why you want to try it. If you are still growing, any type of diet should be avoided. For those who are growing or are active, restricting intake to 500-600 calories is very unsafe. For individuals of all ages, dieting can be mentally and physically harmful in the long-term. It’s also important to think about how IF could affect your social life. For example, if you ate only from 8-4pm, you might miss out on eating at a fun event. In general, it is not safe for anyone who is still growing to try IF, and you should always consult your medical provider before making any changes to your diet.

-Dietitian Elsey