Why Exercise Burns Fewer Calories Than We Think

[00:00:00]The standard story, well, we'll call it the additive model. Let's say I burn 2,500 calories a day today and I have I'm pretty sedentary. Well, let's say I'm going to change my lifestyle and I'm going to add 300 calories a day of exercise to that. So, on average I'll be running 3 miles a day extra. The additive model would say, well, I I was burning 2,500 calories a day before I started the exercise program. Now, I'm exercising and I'm going to have 300 calories a day more than that, so I should burn be burning 2,800 calories a day. That's the standard way of thinking about it. Your exercise just adds up to whatever you were doing before. That's why we call it additive. What we've learned is that actually that that's not really what happens. It'll work like that for a few weeks, maybe, as your body's adjusting. But after your body adjusts to that new lifestyle, if we check in with you a few months down the road, you're not burning 2,800 calories a day, which is what we would have expected. You're burning substantially less than that. And it's because your body has adjusted to kind of make room for that new exercise you're doing and it doesn't show up anymore in the total calories a day that you're burning.