Exercise helps burn more calories – but not as much as you’d think

It’s generally accepted that exercise is a key element of losing weight. But this long-held view has been called into question in recent years – with no shortage of articles and podcasts claiming it’s a myth that exercise increases your metabolism and helps you burn calories after you work out.

The central tenet of these reports is that the amount of calories we burn each day is somehow constrained. This hypothesis was first proposed in 2012 by the evolutionary anthropologist Herman Pontzer. He posited that as you increase your daily energy expenditure (calories burned) through physical activity, your body will find ways to cut back on energy expended on other biological processes – such as your resting metabolism. This leaves your overall daily energy expenditure unchanged.

This theory has since been popularised in Pontzer’s 2021 book Burn, in which he theorises that “we burn calories within a very narrow range: nearly 3,000 calories per day, no matter our activity level”.

Building on this, Pontzer suggests that, “The bottom line is that your daily (physical) activity levels have almost no bearing on the number of calories that you burn each day.”

But before you pack away your running shoes, let’s look at what the research shows us. The most rigorous and robust evidence available on the topic actually shows that exercise…

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