Why Jillian Michaels Has Reversed Her Thinking on Two Controversial Health Practices

Well, cheers, because that's exactly what's happened. Backstage at Livestrong's Stronger Weekend event in Los Angeles, Jillian Michaels, creator of the My Fitness app and former trainer on The Biggest Loser, tells me that research for her latest book, The 6 Keys: Unlock Your Genetic Potential for Ageless Strength, Health and Beauty has actually changed her mind on—of all things—alcohol.

This reversal is due to the fact that the book looks at health data from an anti-aging standpoint rather than from a weight-loss perspective. "I was always like, 'Alcohol is the devil, it’s the worst thing for weight loss, and it is...But there are so many studies looking at [the benefits of] dark alcohols in limited consumption," she says. Among its specific benefits she lists alcohol's ability to increase glymphatic function (meaning, how waste is cleared from the central nervous system) and says the resveratrol and antioxidants found in alcohol are anti-aging and protective of heart health.

"I was always like, 'It doesn't matter when you eat or when you don't eat, all that matters is how much you eat,' because I was looking at it from the weight-loss perspective...However, when it comes to anti-aging, it does matter." —Jillian Michaels

Still, she says, this turnaround doesn't mean she's all for going off the rails. "It's no more than two drinks a night," she says, noting that if you drink too much, you increase your risk of breast cancer, ovarian cancer, and weight gain [also, perversely, dementia]. "My thing is no more than six drinks a week, tops... and not in one night." (I should note that a recent buzzy study showed that no amount of alcohol is technically "safe" for consumption, but that conclusion is not without its critics.)

Research for the book changed her mind on another hot topic in today's wellness world, too: intermittent fasting. "I was always like, 'It doesn't matter when you eat or when you don't eat, all that matters is how much you eat,' because I was looking at it from the weight-loss perspective," she says. "And it's true from that lens; however, when it comes to anti-aging, it does matter." She now believes, she says, in the benefits of intermittent fasting on longevity and says she tries to limit her daily food intake to the period between 8 a.m. and 8 p.m.

You'll have to read Michaels' book to get the specific intel that changed her mind on this issue, but Mark P. Mattson, PhD, senior investigator at the National Institute on Aging’s Laboratory of Neurosciences, recently told me that mice put on an alternate-day fasting schedules when they're young—one day on, one day off—live 30 percent longer than mice on regular feeding schedules. In other animal studies, he said they've found that intermittent fasting, whether it's alternate-day fasting or 18-hour windows without food daily—increases the resistance of nerve cells to stress. This can also slow aging.

Based on that interview, I started to toe-dip into the intermittent fasting pool, and it's reassuring to know such a prominent fitness guru is doing the same. Michaels' change of heart on these two issues proves it's not always beneficial to be stubbornly dogmatic about diet, in large part because new evidence presents itself for consideration constantly. Before writing her new book, Michaels says she was always judging whether practices helped make you thin or fit. "[I wasn't] looking at what’s protecting your cells, your macromolecules, your DNA strands, your telomeres," she says. Bottoms up to this face-saving (literally, not figuratively) about-face!

Can't get enough of Jillian? Find out which 3 foods she says are wrecking your metabolism. Also, here's the intel on why she's never experienced a 4 p.m. slump.