The protocol encourages “anti-aging magic.”
Hungry athletes should consider a pseudo fast.
While alternate-day and intermittent protocols require you to go several hours or even full days without food, the fasting-mimicking plan essentially tricks your metabolism into thinking you’re on a prolonged fast—while allowing you to eat.
Here’s how the five-day plan, which was developed by Valter Longo, Ph.D., a professor of biological sciences at the University of Southern California in Los Angeles, works: On day one, you’d consume about 1,100 calories—with some variation depending on gender, activity levels, and weight—then 725 on each of the next four days. Your protein intake should be much lower than normal throughout (more on the macro breakdown below).
Calories and protein signal to your body that it's getting fuel, explains Robin Foroutan, RD, an integrative dietician at The Morrison Center in New York City. By keeping amounts of both comparatively low for several consecutive days, you “sneak past that metabolic cascade of effects and your body thinks that it’s fasting.”
Since you’re allowed to eat, you can still exercise during the five fasting days—and fasting-mimicking could even help you recover from workouts more quickly since it eases inflammation, she adds.
In fact, it elicits several benefits similar to those you'll get from more extreme fasts. It has been shown to improve blood sugar and cholesterol levels, reduce the presence of a specific gene associated with cancer, and help you lose visceral fat, the dangerous kind that surrounds your organs, Foroutan says.
“And it increases production of stem cells,” Foroutan notes, which are used for repair and linked to longevity. "That's the anti-aging magic." You'll get the most benefits if you eat primarily vegan during the five-day plan, with one or two servings of fish.
Adds Romina Ines Cervigni, Ph.D., a nutrition biologist who studies fasting-mimicking at the Valter Longo Foundation in Milan, Italy: “The idea is that the body enters a more protective mode and prioritizes removing damaged cells and tissues.”
Research shows the benefits kick in once you adhere to the plan three months in a row. That said, you could try it every month or alternate months for as long as you’d like (with your doctor’s approval) to see if it works for you.
Here, the plan's specifics and who should try it.
How to do it:
On day one, your macro totals should be about 11 percent protein, 46 percent fat, and 43 percent carbs (that’d be about 30 grams of protein, 56 grams of fat, and 117 grams of carbs if you eat 1,100 calories).
For the next four days, they’d drop to 9 percent protein, 44 percent fat, and 47 percent carbs—or 16, 35, and 85 grams, respectively, on a 725-calorie diet.
On all five days, it’s important to stay well-hydrated; aim for two to three liters of water a day, Foroutan says. While you can take part in low- or moderate-intensity workouts (like yoga or a steady-state, five-mile run), you should avoid vigorous exercise like HIIT and heavy lifting so your body has energy to create stem cells, Foroutan says. You can, however, stick to your regular fitness routine before and after those five days, so you can even try it during high-volume training blocks.