For months, Juna Gjata, the co-host of WBUR's new podcast, "Food, We Need To Talk," asked every eating expert she interviewed the same question: "If you could tell people to change only one thing that would have the biggest impact on their health for the rest of their lives, what would it be?"
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Their expertise ranged from nutrition to metabolism to how super-tasty foods affect the brain. She expected them to answer with pointers like "eat more vegetables," or "increase your protein," or "cut down on the cheesecake."
But, limited to just one recommendation for lifelong health, none of them focused on food. All had the same answer: just exercise.
And several focused on one particular type: resistance exercise — also known as strength training — as the best benefit for the least amount of time.
So, with 2020 just around the corner, here's an edited preview of an upcoming episode of "Food, We Need To Talk," with the hope it might help inform your New Year's resolution thinking. Juna is joined by her co-host, Dr. Eddie Phillips, founder of the Institute of Lifestyle Medicine.
They begin by looking back at Juna's old misconception about exercise as simply a way to burn off calories on the treadmill. Eddie notes that actually, the most important thing about exercise is that it increases and maintains muscle mass.
Juna: I asked Dr. Wayne Westcott, director of the Exercise Science Program and Fitness Research Program at Quincy College, why is having high muscle mass so important?
Westcott: Great question. Muscle not only burns calories and uses energy when you're active; when you're at rest, muscle also burns lots of energy — so much energy that it makes up about 30% of your resting metabolic rate. When you're sound asleep at night, your muscles burn 30% of your calories.
Juna: Your resting metabolic rate — that's basically all the calories your body burns when you're doing nothing — lying down, sleeping, breathing.
Eddie: Right, just keeping the lights on. And it becomes even more important as we get older, because the natural course of events is to actually lose muscle mass. Our metabolism just slows down. And the way that we raise our metabolism is not green tea supplements or apple cider vinegar shots — there's no science backing them. There's lots of science, though, for good, old-fashioned exercise.
Juna: So we should hit the treadmill?
Eddie: Well, not so fast. Not all exercise is created equal. Cardiovascular exercise like on the treadmill is really great for your heart, your lungs, your brain and your stress levels. But if you actually want to build your muscles, you've got to do what we call resistance training. That's the scientific term for lifting weights, using bands, your body weight, anything that stresses your muscles. It's also called strength training.
Juna: Honestly, the reason that I never got into it was because it really doesn't look like it burns that many calories. Lifting weights just looked so chill. I didn't think it would do anything.
Eddie: If you're just counting calories, Juna, you're absolutely right. You're not burning a lot of calories to lift those weights. But your body actually has to remodel itself after you've stressed it, and that takes even more calories.
Juna: That was the coolest thing that I ever learned about exercise: Basically, a human being is an adaptation machine. We're meant to adapt to the stresses we put our body through. So if you go out in the sun, your skin gets tan to prepare for the next time you're in the sun. Or if you're doing really laborious work with your hands, they grow calluses. That's how fitness podcaster Sal Di Stefano talks about exercise, and it's what finally got through to me.
Di Stefano: When you do lots of cardio, where you just get on a treadmill and jog, jog, jog, or you get on an elliptical and go forever, the body is getting a couple of different messages. It's getting the message, "We need stamina and endurance." And it burns a significant amount of calories, so we probably want to become more efficient. We don't need much strength. So, a great way to become more efficient at calories is to pare down muscle.
Eddie: So if you're picturing who's going to win the next marathon, you know what they look like. They're going to be slim. They're going to have near zero fat on them. Small and just fast. They're not carrying a lot of extra muscle mass around.
Juna: Exactly. On the other hand, resistance training sends a pretty different message.
Di Stefano: Resistance training doesn't burn a ton of calories when you do it, but it is sending the signal to your body that's saying, "We'd better build more muscle and more strength to be able to handle this stress." Because when you lift weights, that's what you're doing: stressing the body. It's why you get sore. So your body's OK with becoming less efficient with calories. It's OK with speeding up its metabolism because you're constantly telling your body, "We just need to be stronger."
Eddie: And when you're doing that resistance training, it's not just building up the muscles. It's actually that the muscles that you have become even more metabolically active. Here's how Wayne Westcott describes it.
Westcott: People who don't strength train, if they run or walk or swim or bike, their muscles burn about six calories per pound per day, which is great. That's a lot. People who do strength training, their muscles burn, at rest, nine calories per pound per day, 50 percent more. Resting metabolic rate increases when people strength train by between 5% and 9%, the average being seven in almost all the studies. That's huge in terms of maintaining a better body weight, and sustaining your body weight, which is the biggest issue in the United States.
If we didn't have scales, just had full length mirrors, people would do a much better job of deciding what kind of exercise they should do or not do.Wayne Westcott
Eddie: Seven percent doesn't sound like a lot. But it adds up to about 250 calories a day. That still doesn't sound like a lot, but over the course of a year, it's 20 pounds' worth of calories.
Juna: And Wayne Westcott found in his studies that when people diet down — and they're not doing any exercise, they're just dieting — they'll lose muscle and fat. So you're not just losing fat. You're losing muscle, too. Now, if you're anything like me, your natural inclination when you diet is to also run your little butt off on the treadmill.
Westcott: It increases the fat loss. But guess what? It also increases the muscle loss significantly. It exacerbates the aging process of losing muscle. When they do strength training plus diet, they lose the least muscle and they lose the most fat.
Eddie: So resistance training is perhaps the best exercise to use if you're trying to lose fat.
Westcott: In our studies, the average person loses about one pound of fat per month when they strength train, and they add about one pound of muscle per month. So the body weight tends to stay the same. And people say, kind of surprised, "Well, I haven't lost weight, but I'm wearing different pant sizes, or dress sizes. You know, and my waist is smaller, my hips are smaller." Well, that's because muscle is more compact, more dense than fat. If we didn't have scales, just had full length mirrors, people would do a much better job of deciding what kind of exercise they should do or not do.
Eddie: But we're not just talking about resistance training. We still want everyone to be doing their 150 minutes a week of exercise that raises your heart rate. It's going to take care of other problems — your risk of diabetes, of osteoporosis, of cancer are all going to plummet the more active you are. You're going to live longer and live better. And in the meantime, psychologically, there's no medicine like exercise.
Juna: That is what I find to be the best part about going to the gym, for sure. The stronger I feel in the gym, the stronger I feel outside the gym, too.
Eddie: Also, the physiologic effects of starting to lift weights actually come much quicker than just going on the treadmill. For patients who have obesity, we start with resistance exercise. And the psychological benefit comes very quickly when you realize that you can and will get better from a little bit of hard work. And you really don't have to do that much exercise to get the most results. Which is good news for a lot of us, because the time intrusion of exercise is still what gets most people not to start and not to continue. And remember, what we're trying to do is get people to change in small ways, and to commit to changes that they're going to enjoy and do for the rest of their lives. It's not a 12-week beach body challenge. And the research shows that with the resistance training that we've talked about, two or maybe three times a week is all you need. And a half hour at a time, you're going to see those dramatic results. It's almost like an inoculation. It's just enough to get your muscles moving.
Juna: So what's best to do at the gym?
Eddie: If you want a simple answer? Shameless plug: Listen to The Magic Pill [the previous season of this podcast.] But if you only had one exercise to do, I would say squatting. Get the proper form. Up and down off of your chair, just to strengthen your legs, get into your core. You're also going to work your arms, by doing a little bit of pushups. If you can't do them on the floor, do them against the the edge of a table. And you're going to work your core. If you do that, your life has already changed. If you're overweight, the best thing you can do to carry that weight — until hopefully you lose it — is to make your muscles stronger. That then is going to take the stress off of your joints. Get some guidance. This is not something that everyone knows how to do. So if you can, find a trainer or use YouTube videos.
Juna: And if you feel self-conscious about the gym, here's what Sal Di Stefano says:
Di Stefano: I'll tell you something right now: One of the most empowering things you could do is overcome a fear like that. Nobody knows what they're doing at first. Nobody cares. People who work out couldn't care less that there's other people working out at the gym. Just go to the gym, put your headphones on and go take care yourself and don't let anything stop you, especially fear. Start small. Go easy. Once you start to get used to going to the gym, you start to find yourself getting stronger. You're going to be a more empowered individual.