This Is How Long It'll Take For Intermittent Fasting to Work

Two of the more well-known intermittent fasting plans are the 5:2 diet and the alternate-days approach, Liz Weinandy, a registered dietitian at Ohio State University’s Wexner Medical Center in Columbus, OH, tells POPSUGAR.

“Under the 5:2 diet, individuals eat normally but healthfully for five days of the week and consume only 500 to 800 calories on two nonconsecutive days,” Weinandy says. “On the restricted-calorie days, some might opt to split their calories into two or three mini meals.”

Under the alternate-days plan, Weinandy explains you would eat normally one day, then fast for part of the day and eat fewer than 600 calories the next day.

A third, though less popular, approach is an everyday method, in which individuals restrict their eating to six to eight hours only, every single day, without altering their caloric intake. A popular option is the 16:8 plan, in which you fast for 16 hours and eat for eight.

Have you ever heard the phrase “breakfast is the most important meal of the day”? According to Sriram Machineni, MD, director of the Medical Weight Clinic at the University of North Carolina at Chapel Hill and assistant professor at the UNC School of Medicine, it is.

A recent study may have confirmed just that when it showed that people who ate closer to the time when their bodies released melatonin – “at the onset of sleep,” Dr. Machineni says – had higher weight and higher body fat percentages than those who ate earlier. What this means, anecdotally, is that if you start your calorie consumption right when you wake up, you might have better luck with weight loss.

Weinandy says that results are usually apparent around the 10-week mark, adding that she sees an average weight loss of seven to 10 pounds over that period through any of the three approaches to intermittent fasting mentioned previously.

It might take longer than that since everyone’s metabolism works differently. “I tell people who make any diet change to give themselves one to two months,” Weinandy says. On the other hand, “if you’re losing weight too quickly, you’re doing it wrong.” In that case, you should re-evaluate your calorie intake.

Our experts say studies are inconclusive so far, but because you’re eating healthier and fewer calories, the method could have an impact beyond the scale and on your overall health, including your cholesterol, triglycerides, and blood sugar levels.

“Some of my clients do intermittent fasting with no problems, but this is very individual,” Weinandy says, adding that people who are pregnant and those with blood sugar problems should check with their doctors before trying intermittent fasting.

She adds that the 16:8 method seems to be the most sustainable. “As long as a person isn’t experiencing nutritional deficiencies, they can follow this program for the long term,” Weinandy says.