I Went on a Quest to Fix My Metabolism. Here’s What I Learned

My metabolism, it seems, has fallen off a cliff.

I first noticed that things weren’t quite as they should be this past spring. After last year’s period of festive indulgence, I hit the gym again, dialed up my running, and locked in my diet in the same way I have been doing for the past five years. Only, at age 35, all my usual hacks didn’t seem to be having the same effect. I’ve never been super in shape, but usually a few weeks of work would leave me fairly happy with how I looked. Now, no matter how much I run or diet, I can’t seem to lose weight.

“We’re cooked,” says my friend Joel when I bring this up. Joel has an active job, and he’s been running 40 miles a week to and from work—and he has kids to keep him busy. But we’re both in the same boat. “I’m not losing any weight, even with all this running,” he tells me.

Instead of giving in to the cruel ravages of time, I thought I’d try and do something about it. I contacted the best experts around to see if they could help me, Joel, and you understand what metabolism actually is, and how we might kick-start it once it starts to slow down.

What is metabolism, exactly?

“Your metabolism is a combination of many factors which can change as we grow,” says Dr. Gareth Nye, a lecturer in biomedical science at the University of Salford. “One important factor is your basal or resting metabolic rate (BMR)—the number of calories you burn as your body performs basic life-sustaining functions, or essentially the calories you would burn staying in bed.”

As a teenager, someone might have remarked on your ability to lie around all day, eat burgers, and still be slender, attributing this to a fast metabolism. The thing is, our bodies aren’t growing as they did when we were younger, so keeping the metabolic fire stoked now takes a bit more work. Especially when you factor in the more sedentary and stressed life of a middle-aged guy.

“There’s no coincidence that most people complain about being unable to lose weight in their 30-40s as it’s normally when adults are at their most stressed and busy with work and family,” says Nye.

Why are things slowing down now?

“Your body is doing exactly what it was designed to do,” says Dr. Harpal Bains, a longevity doctor and medical director at Harpal Clinic. “From an evolutionary perspective,” she continues, “men were built to peak in their late teens and early 20s to compete, reproduce and protect the tribe. By your 30s, testosterone starts to decline, muscle-building slows and your metabolism downshifts.”