A new gym-goer finds an exercise routine, sticks with it, and the pounds start coming off at a regular clip—until something changes. Not the person; they’re still exercising as hard as ever, sometimes harder, but the weight loss has stopped. What happened?
A new study in Current Biology looks at the problem that’s plagued some (though not all) exercisers, and concludes that it probably wasn’t anything they changed that caused the problem. Instead, it was something that they didn’t.
Essentially, non-exercisers see a big benefit in weight loss right at the start of a new regime. But, once they’ve made the transition over to becoming a regular exerciser, their exercise routines (although they may stay the same or increase) are no longer showing big results. Even if they keep upping their exercise levels, sometimes by quite a lot, the jump in the energy they burn when going from almost no exercise to some exercise is never really replicated. Hence, there is a plateau in weight loss, to the frustration of many exercisers.
It’s no big surprise that a regular runner—as legs and lungs get stronger—starts to find the routine less and less taxing to the body. But what can we draw from all this about how weight loss really works? According to the study authors, while the change from not exercising to exercising is a big one, after that, our bodies tend to adapt to increases in activity to keep our energy levels roughly in-check. Even regularly increasing exercise is unlikely to burn up so many calories to drive weight loss on its own.
So trying to figure out how much weight loss exercise can cause may simply be the wrong question to ask. Perhaps there are better reasons than weight loss for people to exercise. It can help with weight loss, but it has much more measurable gains in improving strength, stopping loss of muscle or bone mass as you age, and even in enhancing mood.
So, does exercise help people lose weight? The best answer seems to be yes, to a point—but the reasons to keep doing it reach much further than that.
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