Does your metabolism slow down in your 40s?

On Ologies (the "Evolutionary Anthropology (METABOLISM)" episode, January 2024), evolutionary anthropologist Herman Pontzer took a listener question that host Alie Ward read out, one many adults ask themselves: why does my metabolism suck? His answer in that conversation was that it doesn't. Then he described a study he took part in, which mapped how much energy people burn from birth to old age, once body size is taken into account.

it really doesn't change with menopause, it really doesn't change as testosterone levels go down in men.

Herman Pontzer, Ologies, 2024

What he described

Pound for pound, Pontzer said, energy use peaks around age one, comes down through childhood and the teenage years, and reaches the adult level in the early twenties. From there it holds steady through the late fifties. After about 60 it starts to decline, and he called that decline real. He admitted he had expected something else: in his forties, he was sure his own metabolism must be slower than it was at 30.

He added that people whose metabolism runs a little slower aren't necessarily more likely to gain weight. In his view, the trouble usually sits elsewhere:

your metabolism's great; it's your brain that's giving you trouble

Herman Pontzer, Ologies, 2024

By "brain" he meant appetite, in a world where tasty food is cheap and close at hand.

What the guidance adds

The study Pontzer described isn't among the sources this program draws on, so take its details as his account. The guidance we do hold fits his main point and adds nuance. France's national health authority (HAS), in its 2024 care guide, says weight gain around menopause is common but not inevitable, and varies a lot from one woman to the next. It names a mix of causes: hormonal and physical changes, less physical activity, disturbed sleep, disrupted routines, and stress and what it does to eating. It also notes that fat tends to move toward the waist in these years. So hormones play a part, even if a slower engine isn't the main story.

After 60, the picture changes, as Pontzer said. The World Health Organization's 2020 activity guidelines ask older adults (65 and over) to include balance and strength training, at moderate or greater intensity, as part of their weekly activity.

What to look at instead

If the scale crept up in your forties, the useful question is what changed around you. A new job, children, caring for a parent, a longer commute, shorter nights: each one can shift when you eat, how much you move and how you sleep, often without a single decision.

How this fits the Lose weight sustainably program

The program starts where Pontzer points: your day, as it is now. In the free first chapter you describe a usual day of eating in your own words, and your answers point to one of four patterns, such as running on empty until evening or eating what happens to be in front of you. The paid chapters then walk one day with you, from your first meal to bed, setting habits for your plate, your long gap, moving and sleep, and you leave with two habits to start, fitted to the life you have now. Start Lose weight sustainably: the first chapter is free.

Source: Ologies, "Evolutionary Anthropology (METABOLISM)" with Herman Pontzer, 31 January 2024 Research: HAS, Guide du parcours de soins: surpoids et obésité de l'adulte (2024) · Bull et al, WHO 2020 guidelines on physical activity and sedentary behaviour (2020)