3 Effective Fasting Methods for Weight Loss, Science Says
Since it's been a trendy eating habit for a while now, you've likely already heard of intermittent fasting, or IF for short. If you're trying to lower the number on the scale, variations of this diet offer minimalist approaches to losing weight.
"Any time we have a calorie deficit, there will be weight loss," Jenny Fontana, NT, NCRC, NCFAC, who instructs certified nutrition coaches, tells Eat This, Not That!.
There are several different forms of intermittent fasting, some of which may be more practical weight loss interventions than others. A study recently published in JAMA Network highlighted three methods found to be particularly effective.
Related: Intermittent Fasting Can Lead to "Significant" Weight Loss, New Research Says
"This study is essentially a review of review articles. It demonstrates that the different forms of intermittent fasting (i.e., alternate day fasting, the 5:2 diet, and time-restricted feeding) are all effective weight loss interventions for people with obesity," Krista Varady, PhD, co-author of the study and a nutrition professor at the University of Illinois, Chicago, told Medical News Today.
Beyond weight loss, IF also offers a wealth of science-backed health benefits—here are seven to be aware of. But first, here's a breakdown of the three forms of intermittent fasting name-checked by Varady.
Alternate day fasting
Followers of alternate day fasting adhere to a schedule that switches back and forth between eating and fasting. Those who abide by this diet alternate between one feast day and one fast day, which typically includes a 500-calorie meal.
"The trick is to make sure you are still eating healthy on days when you are not fasting," Heather Hanks, MS CAM, nutritionist and medical advisor at Medical Solutions BCN, tells Eat This, Not That!. "If you overindulge in calories from refined sugars and carbs, you'll throw your insulin and hunger hormone levels off and wind up storing more glycogen than you're burning."
Healthline notes that "the most popular version of this diet is called 'The Every Other Day Diet' by [Varady], who has conducted most of the studies on ADF."
5:2 diet
Followers of the 5:2 diet eat an unrestricted diet for five days of the week and fast for the remaining two.
When it comes to long term compliance with the first two diets on this list, Shadi Vahdat, MD, the medical director at LiveWell Integrative Medicine, offers a word of caution.
"While the alternate day fasting, 5:2 diet, and time-restricted feeding can all be effective in weight loss, reduction of body fat and the associated metabolic improvements that come with them, long term compliance with the alternate-day fasting or 5:2 diet can become very challenging," Vahdat tells Eat This, Not That!.
Time-restricted feeding
There aren't calorie restrictions in time-restricted feeding, but followers of this method only eat during a daily window of four to 10 hours. Fasting occurs outside of that designated eating window.
"The most practical and feasible option for a lot of people turns out to be time-restricted feeding," Vahdat tells Eat This, Not That!. "If done correctly with daily overnight fasting of anywhere between 12-14 hours, then the benefits can be obtained long-term with none to minimal side effects."
To learn more about fasting for weight loss, check out Doing This Before Fasting Can Speed Up Your Fat Burn, New Study Says. Then, don't forget to sign up for our newsletter for more of the latest health and food news!
