The Linear vs Constrained Model Of Exercise

One thing we've learned is that exercise is not linear. Exercise is not endless in the amount of calories that it can burn. Studies have shown that you cannot simply just do more exercise to burn more calories and therefore increase your total of daily energy expenditure. We now believe in a constrained model of physical activity. That you can exercise up to a certain point and you will burn more up to a certain point. But you can not burn more calories beyond a certain point.

Figure: the old additive (linear) model on the left and the constrained model on the right. Schematic redrawn from Pontzer H et al., Current Biology 2016.

• Left: what we used to believe. Every extra workout adds calories on top of everything else.
• Right: what was measured in 332 adults with doubly labeled water. Total burn rises at first, then levels off.
• The grey area shrinking on the right is your body cutting back elsewhere (less fidgeting, less movement, NEAT) to pay for the exercise.

This is the previously believed linear model of physical activity. We used to believe that the more you exercise, the more calories you burn. This is no longer true.

We now know that there is a cap to the amount of calories you can burn with exercise. When you first start exercising you will burn more calories up to a certain point, then you no longer burn more calories. In fact, your body will downregulate other parts of your total daily energy expenditure to make up and compensate for it. This usually comes from non exercise activity thermogenesis (NEAT). You will stop fidgeting, stop moving, stop walking as much, and stop doing other imperceptible movements that you didn't even know you had.

Here's the study if you want to look at it and of course you can watch my very in-depth exercise YouTube video. Go to DrAlo.tv and search for "In Depth Exercise Research Review".

Watch me explain this on YouTube:

https://www.youtube.com/watch?v=82NKcRYbToA

So What's the Solution?

The answer is diet. Dr. Alo's Dietary Guidelines show the evidence-based approach to eating. Learn why diet is more important than exercise for weight loss.