Written by: Vivian Schemper, Nutrition & Wellness Specialist

Intermittent fasting has gained considerable popularity in recent years, and many people find it easier to follow than a traditional calorie restriction diet. Supporters claim that intermittent fasting can prevent (or reverse) diabetes, encourage long-lasting weight loss and even prevent cancer and heart disease. While many of these benefits have been backed by research, it is important to consider the risks and determine if it is appropriate for you.

THE OPTIONS

There are three common types of intermittent fasting:

• The 5:2 plan: involves restricting food intake 2 days per week (usually eat ~500 calories on fasting days) while allowing normal eating the other 5 days per week.
• Alternate-day fasting – alternates days of zero calories with days of unrestricted calories.
• On-time restricted fasting – food consumption is restricted to a 6-8-hour window.

THE SCIENCE

A systematic review published in 2015 looked at 40 studies and found that intermittent fasting was effective for weight loss (typical weight loss was 7-10 pounds over 10 weeks). While many studies were reviewed, many of them were not of the highest quality and some had a very small number of participants.  In 2017, a randomized controlled trial (the gold standard of research) followed 100 obese individuals for one year. They found that intermittent fasting was not any more successful for weight loss than just cutting your calories every day. Plenty of research exists on the benefits of intermittent fasting, but most have been done on rodents—not humans.

THE BOTTOM LINE

It is likely that those who engage in intermittent fasting are losing weight and improving their health based on the simple premise that they are reducing the number of calories they normally consume.

Severely restricting calories 2 days per week, just so you can eat whatever you want on the other days is not the key answer to overall health and wellness. If intermittent fasting is easy to follow and you are able to make healthy choices on the days you are not fasting, go for it. If intermittent fasting is a miserable experience for you, it may mean that fasting is not right for you—and that’s perfectly okay! There are plenty of other ways to eat that can promote weight loss, support a healthy weight and keep a healthy body.

A FINAL NOTE: WHO SHOULD NOT DO INTERMITTENT FASTING? Anyone who has been diagnosed with diabetes (both type I and type II), who are on medications for diabetes, people with a history of eating disorders, and/or pregnant or breastfeeding women should not do intermittent fasting. If you fall under these categories and you are interested in intermittent fasting, we recommend speaking to your healthcare provider for their advice and guidance.