Intermittent Fasting – does it help Weight Loss?

timed eating

By Maggie Zeng, UC Davis Nutrition Peer Counselor

The concept of intermittent fasting continues to grow in popularity; people tout the effect of fasting on weight loss or even report it boosts their mood. There are many versions of intermittent fasting, including the “16/8 method”, “5:2 diet”, and “Eat-Stop-Eat”, among others.  Is there any evidence that fasting is advantageous?

What is Intermittent Fasting

Intermittent fasting is a way of scheduling your meals into a restricted time frame. You are not necessarily changing the amount of food eaten, rather you’re changing when you eat.

There are three common ways of intermittent fasting:

16/8 method

This method splits a day (24 hours) into two blocks. One is 16 and the other 8 hours long. During the 8 hour block, you eat whatever you want (the amount of food you normally eat for a day). You may still eat 3 meals within the 8 hours or skip one meal. During the 16 hour block you fast, drinking only water.

16_8

5:2 Diet

The 5: 2 Diet is a weekly pattern during which five days a week you eat normally, and two days (recommended not consecutive) you limit your calorie intake to below 500-600 kcals.

Eat-Stop-Eat

This method involves a 24 hour-fasting period once or twice per week. During the fasting day, only water, black coffee and other non-caloric beverages are allowed.

Any benefits?

Potential benefits to intermittent fasting include possible weight loss due to decreased calorie consumption, possibly a positive effect on blood glucose control (more research needed) and enhanced brain health.  One study found that mice on a brief intermittent fasting diet had better learning and memory than mice with free access to food.  Further research, in animals, suggests that intermittent fasting can suppress inflammation in the brain, which has links to neurological conditions.

What about the down side?

Potential pitfalls include individual tolerance to fasting times – some people find it convenient to skip meals, others find it difficult. Overeating during non-fasting times can contribute to excessive calorie intake and weight gain. Finally, the lack of research on long term effects prevents these regimes from being a recommended practice.  Talk to your medical provider if you are considering any new eating pattern.

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Harvard Health Publishing. “Not so Fast: Pros and Cons of the Newest Diet Trend.” Harvard Health, https://www.health.harvard.edu/heart-health/not-so-fast-pros-and-cons-of-the-newest-diet-trend.