If there’s anyone who knows how to increase longevity and healthspan, it’s Mark Sisson, founder of Primal Kitchen and author of the Two Meals a Day Cookbook. Sisson is turning 69 years old in July, but he looks and feels more than 20 years younger—in fact, he has just as much energy as he did when he was training for the 1980 Olympic Trials; he has just relinquished a consistent running schedule in favor of Frisbee. 

Today, Sisson follows a holistic approach to sustaining all-day energy well into his 60s. On this episode of the mindbodygreen podcast, he shares some of those nonnegotiable nutrition and fitness tips, and we grabbed the highlights below: 

Sisson is a huge fan of time-restricted eating. He typically eats two meals a day, with his first meal around 1:00 or 2:00 p.m. and dinner at 7:30. “One of the benefits is the creation of metabolic flexibility,” he notes. “So you become very good at burning fat in addition to burning sugar.” When you’re able to burn off your stored body fat, he adds, you extract energy from your own body, rather than needing another hit of glucose to feed the blood sugar crash. Thus, you may naturally have more energy. 

“Your body becomes so metabolically efficient that you extract energy from your body fat [and] from ketones, so there's an efficiency that begets an added sense of energy and the empowerment that energy brings,” he adds. In addition to feeling younger, time-restricted eating may come with real longevity benefits: A recent study from 2019 found that people who followed a time-restricted eating plan in which all meals were consumed between 8 a.m. and 2 p.m. had multiple genes associated with longevity (including one that upregulates autophagy). 

Of course, everyone may benefit from a different time-restricted eating plan, and your schedule likely won’t look identical to Sisson's. But the key is finding your own sweet spot for metabolic flexibility. You can read all about the different types of intermittent fasting plans here. 

Sisson enjoys what he calls a “fire and ice” practice (aka, hopping from a cold plunge to a steam room or sauna), as brief yet intense cold exposures have been associated with a balanced inflammatory response, improved sleep, muscle and joint health, and mood support. Plus, a cold temperature activates the production of brown fat, which breaks down blood sugar and fat molecules to create heat. In doing so, that brown fat can create healthy metabolic shifts. 

However, Sisson stresses the importance of brief cold exposures. “With cold plunges, we tend to get caught up in the game of it and not looking to optimize the benefits,” he explains. Many people think spending longer in an ice bath begets more benefits, but a few minutes (or even just 30 seconds) is really all you need to reap the health advantages. In fact, like fasting, you may experience negative effects if you overdo it. “More is not better—maybe more is significantly worse,” Sisson says. 

Sisson doesn’t believe one type of exercise is the best for vibrant energy levels. Whatever you choose, though, it must be fun: “I haven't run a mile in 25 years,” he says. Rather, “I started playing games. I started playing ultimate Frisbee, so I'm doing a lot of running, but I'm not going out and running 10 miles,” he says. Sisson also loves to paddleboard and ride his fat bike on Miami beach—both of which require a blend of strength and cardio. “[It] keeps me lean, fit and entertained enough without really having to manage pain,” he explains. 

That way, exercise feels more like a fun, energetic activity than a chore. And when you love a specific type of workout, chances are you’ll engage in the movement more often. 

Hormetic stressors like fasting, exercise, and cold plunges can have a significant impact on your energy levels. Of course, it is possible to go overboard, so make sure to find your sweet spot and stick to it. That way, you can feel more vibrant long-term without stressing your body too far.