The Complete Guide To Intermittent Fasting

IT’S NOT OFTEN THAT AN ANCIENT Greek scholar and a Kardashian agree, but the rising popularity of fasting has made strange bedfellows. Athenaeus of Naucratis, who died in the third century a.d., said of fasting that it “cures diseases, dries up bodily humors, makes the mind clearer and the heart purer.” For her part, Kourtney Kardashian has raved about how intermittent fasting allows her to eat what she wants and retain her sleek physique. What is this age-old yet totally of-the-moment method? In simple terms, intermittent fasting, or IF, puts the emphasis on when you eat rather than what you eat. And research is showing that, as Athenaeus proclaimed, it can be good for both mind and body, while also (as Kardashian has found) helping you lose weight. That growing body…

✱ Are underweight ✱ Have a history of eating disorders like anorexia or bulimia ✱ Are pregnant or breastfeeding ✱ Are under the age of 18 You can probably fast, but may need medical supervision, if you: ✱ Have either type 1 or type 2 diabetes ✱ Take prescription medication ✱ Have gout or high uric acid levels ✱ Have a serious medical condition like liver, kidney or heart disease.…

FOR MOST OF HUMAN HISTORY, our primary problem with food was not having enough of it. Famines, scarcity, droughts, wars—these often made the next meal uncertain. People ate when they could, and their bodies adapted to survive during the times when they couldn’t. Fast-forward to the present, and you have a recent study in the American Journal of Clinical Nutrition posing the question: “Do hunger and satiety still affect eating or has recreational (or mindless) eating taken over?” The researchers found that Americans are not only eating more than they were 30 years ago, but they are also eating more frequently throughout the day, “with overall meal patterning shifting from three eating occasions a day to more constant eating among children and adults.” At the same time, surveys from the Centers…

If there’s a reason that Silicon Valley whizzes have embraced IF, it may be in part because of fasting’s profound impact on brain function. Studies have shown several different cellular mechanisms that may account for IF’s apparent brain benefits. One is autophagy, which may help clear cellular debris that could disrupt communication between synapses. A major review of the evidence at the U.S. National Institute on Aging, published in Nature Reviews Neuroscience in 2018, found that IF “impacts multiple signaling pathways that promote neuroplasticity and resistance of the brain to injury and disease.” Ketone bodies that are produced through fasting also appear to have specific benefits to the brain, according to Shelly Fan, PhD. The brain can use only glucose or ketones as fuel, because fat can’t cross the blood-brain…

By doing nothing—simply refraining from eating for a while—you are handing your entire system a welcome respite. In the absence of food, your body can reset and reboot, allowing digestive players like insulin to drop to baseline. Meanwhile, innate cleanup and repair processes can proceed uninterrupted, clearing out dead cells and lowering inflammation. Rather than “starving” and suffering, you’re becoming stronger and more resilient. Here are some of the many ways fasting makes that happen. HEART Several important markers for cardiovascular disease improve after IF, including lower blood pressure readings, healthier cholesterol and triglyceride levels (which help keep arteries clear), and decreased inflammation, which is a big player in heart conditions. PANCREAS This hardworking organ catches a break on IF, as it’s responsible for supplying your body with insulin. IF…

IT’S SAFE TO SAY THAT AS A CULTURE, Americans have developed a fear of hunger. We are deluged with marketing and images that tell us we need that candy bar to stop from becoming “hangry,” and that constant fueling with nuts and cheese and between-meal snacks will keep our bodies (and our metabolisms) humming along. We’ve been warned that getting famished will make us lose control and binge when we can eat again. Hunger has become an enemy, something to be staved off at all costs, rather than as a neutral and natural process. It wasn’t always this way—and rates of obesity have never been as high as they are today. “People graze all day long now,” says Megan Ramos, director of the Intensive Dietary Management Program. “In the Leave It…