Will Intermittent Fasting Help You Lose Weight?

There are many different plans. Here's one you can try without suffering.

Posted Dec 26, 2018

Jimmy Kimmel lost 25 pounds on the 5:2 diet, eating fewer than 500 calories on Mondays and Thursdays then eating whatever he wants the rest of the week. Actor Benedict  Cumberbatch also lost on the 5:2 diet while Hugh Jackman had a different intermittent fasting schedule. Each day he ate during an eight hour period but fasted for the remaining 16 hours. Is this just a Hollywood fad or are there real benefits to intermittent fasting?

Researchers have demonstrated that fasting counteracts a variety of ailments including cardiovascular disease, diabetes, and even diminishing cognition but these findings were based on studies of rats and other laboratory animals where the researcher controlled the animal’s fast. Even if fasting was as beneficial for humans as it is for rats and mice, the reality is that most of us don’t like to be hungry and there’s no researcher to enforce the fast. 

Is fasting worth the effort? A recent metanalysis combined the results of six studies of intermittent fasting found the average weight loss of 15.4 pounds was equal to continuous dieting but both were significantly better than no treatment. It’s hard to draw definitive conclusions based on the results of six studies. Since fasting is difficult for most people, even if it proved to be effective, it might not be a long-term solution to weight control. The 5:2 diet would be more acceptable than a strict fast but many folks would still be miserable on Mondays and Thursdays if they tried to follow Jimmy Kimmel’s example.

Even if intermittent fasting hasn’t proven to be more effective than traditional dieting you may be tempted to try it but reluctant to endure the unpleasantness of going without eating. One type of fast offers a relatively painless way of testing the benefits for yourself. 

Several animal studies demonstrated that intermittent fasting based on daily circadian rhythms prevents weight gain. Mice given unlimited access to high-fat lab chow ate throughout the day and night which resulted in obesity and type 2 diabetes. Other mice fasted for 16 hours and actually consumed the same amount yet they didn’t gain weight or have negative health consequences. The findings suggest that it was the timing of eating, rather than the amount consumed which determined weight gain.

Although the findings with mice are well established there’s less evidence that time restricted eating works for humans. One human study found significant weight loss when participants fasted for 11 hours overnight compared with control conditions. Another study found a 4.1 percent weight loss resulting from consuming a single meal in the afternoon although self-reported hunger was greater the next morning. Other studies haven’t supported night-time fasting for humans so it’s too early to draw definitive conclusions but you might want to experiment to see if it would work for you. 

Edward Abramson, PhD
Source: Edward Abramson, PhD

Although it may be unfashionable, try to have dinner early and once you’ve finished your meal don’t eat anything and limit your drinking to water or tea. You’re just avoiding bedtime snacks and watching TV without nibbling so you’re not on a diet and since you’ll be sleeping for most of your fast you probably won’t be hungry. It should be a relatively painless way to see if intermittent fasting works for you.

References

Patterson, R. E. & Sears, D. D. (2017). Metabolic effects of intermittent fasting. Annual review of nutrition, 37, 371-393.

Abramson, E. E. (2016). Weight, diet and body image: What every therapist needs to know. Eau Claire, WI: PESI Publishing & Media.