Training for weight loss

Opinion: Why Training for Weight Loss is a Waste of Time

We all know that exercise burns calories and revving up your internal combustion engine is key to weight loss. Yet we’re all wrong, says Dr Herman Pontzer. Could our efforts to train ourselves trimmer be a fat lot of good?

The Hadza hunter-gatherer tribe in east Africa averages more physical activity in a day than typical westerners do in a week – but they don’t burn any more calories. That’s because, as Dr Herman Pontzer explains in his book Burn: The Misunderstood Science Of Metabolism (Allen Lane), ‘the armchair mechanic’s view’ of your body as a simple machine isn’t how it actually works. Your body is a dynamic organism evolved to match energy expenditure to fluctuating food intake, manipulating your metabolism accordingly. After all, burning more calories than you eat forces your body to consume itself, eventually to death.

If anything, says Dr Pontzer, your body is like a business with a fixed energy budget: exercise suppresses operations that might otherwise run riot, such as inflammation and stress response. But overtraining can hamper essential functions, which means that it’s not so smart for weight loss.

Men's Health: Your book challenges most people’s understanding of metabolism. What’s been the feedback?

Dr. Herman Pntozer: A lot of folks were positive and thought it was a really new take. People generally felt I make the case pretty strongly, with evidence. There have been two areas of pushback: one is people whose careers depend in one way or another on exercise being a great tool for weight loss; the other is the keto and carnivore bros, who don’t want to hear that we didn’t evolve to eat 100% meat.

MH: Why is metabolism so misunderstood?

HP: Metabolism is the work that your cells do all day, but we’re only consciously aware of a small fraction of that. We’re aware of the energy we spend exercising and of the calories we put in with our food, but the rest is unseen. People tend to be told that metabolism is synonymous with exercise or diet, but it’s a lot more than just that.

MH: Short of handing them a copy of your book, how do you help people understand metabolism at, say, a dinner party?

HP: First of all, I explain to them the Hadza work. I think that makes it very real. You can have this group of people who are incredibly physically active, yet their bodies burn the same number of calories every day as you and me. People find that hard to believe. And then I say, ‘Actually, if you look across species, even within the human population as they get enrolled into exercise programmes, you see much the same thing: exercise doesn’t change how many calories you spend, it changes how you spend them.’ People don’t always buy it, but at least they understand what I’m trying to say.