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.”
All of which makes sense, but it’s a rude awakening for someone trying to convince themselves that they can still hold their own with the younger generation. I don’t want to be over the hill at 35, even if my body’s designed that way.
It gets worse. “You become more insulin-resistant, cortisol (stress hormone) creeps up and recovery takes longer,” adds Dr. Bains. “This makes it harder to stay lean or build strength using the same strategies that worked a decade ago.”
Dr. Bains explains, however, that this isn't failure: It's biology. “Your body isn’t broken. It’s behaving exactly as it was built to,” she says. “But with the right training, nutrition, recovery, and testing, you can absolutely stay strong, lean and high-performing well into your 40s and beyond. You just have to stop fighting your 20-year-old blueprint and start upgrading it and working with it.”
Does testosterone play a part?
Maybe it’s just my algorithm, but social media seems to be awash with testimonials about testosterone treatments and receiving a new lease of life as a result. Bains says that things are supposed to get harder as we get older, but how much of a role does low testosterone play? Is it entirely to blame?
If you’re struggling to remember your secondary school science, testosterone in men is responsible for making sperm, our bone density, muscle mass and strength. “From the age of about 30, men will start to see a natural decline in their testosterone levels as they experience the ‘male menopause’ or ‘andropause,’” says Dr. Shirin Lakhani, an expert in intimate rejuvenation treatments and men’s sexual health at Elite Aesthetics. In fact, it’s a pretty noticeable drop off of about 1.6 per cent per year.
According to Dr. Lakhani, the impacts can include loss of sex drive, erectile dysfunction, mood swings, irritability, loss of muscle mass, fat redistribution (i.e. ‘man boobs’), insomnia and poor concentration and memory. Irritability and insomnia are definitely an issue for me, but it’s difficult to know if they’re linked to T levels or general stress.
“It’s not just about testosterone—other hormones like growth hormone and IGF-1, which support tissue repair and metabolism, also decline with age,” Lakhani says. “Lifestyle factors also play a massive role. Poor sleep, high stress, and increasingly sedentary routines can disrupt hormonal balance and promote fat storage. For example, just one week of sleep deprivation has been shown to significantly reduce testosterone levels in men.”
“Diet matters too,” she says. “Many people in their 30s eat less protein than they should, which can accelerate muscle loss.”
Can I restart my metabolism with food?
Diet seems like a good place to start, so I asked Harry Cox, founder of ClubQ Health, for a magic bullet. It didn’t quite go as I’d hoped.
“I want to eradicate the idea that there’s going to be anything magical you can eat which will fix your metabolism or boost your testosterone,” he warns, but he does add that when it comes to giving my body the best chance at looking good and functioning well, I should think about three things:
- Eating enough calories to promote recovery, muscle growth and hormone production;
- Eating a high-protein diet to support muscle tissue repair and growth;
- Monitoring overall calorie consumption to minimize fat gain.
If you do one thing, upping your protein intake might deliver the quickest results. “Protein has the highest thermic effect of food,” says Cox. “This is the number of calories required to digest, absorb and process the nutrients. Twenty to thirty percent of the calories in protein are burnt simply by digesting it, meaning if you were to go from a low-protein diet (50g) to a high-protein diet (150g), you might increase the calories you burn in a day by 80-120 cals.”
Dr. Nye stresses that a balanced lifestyle is key. Fatty fish like salmon is a great source of omega 3 fatty acids and vitamin D. “An ideal meal might look like a salmon fillet served with sautéed broccoli and a few potatoes,” says Cox—but drinking a beer at night might cancel out the benefits.
However, cutting out carbs completely is not the way. “We can't begin to exclude food groups as this will cause alternative shifts in metabolic processes,” Dr. Nye explains. “Low- or no-carb diets are often associated with increased cholesterol and blood vessel damage which can be deadly, particularly in men through increased risk of heart attacks and strokes.”
Dr. Nye points out that spices like ginger and turmeric are said to improve metabolism, while Bains points to supplements like magnesium, zinc, ashwagandha and even tongkat ali to support testosterone production.
“Time-restricted eating and/or intermittent fasting also helps by improving insulin sensitivity, reducing inflammation and promoting fat metabolism,” says Dr. Bains, “as long as protein and fat intake is maintained to preserve muscle and support hormone production.”
What else can I do?
Cox adds that activity levels are a vital factor, making up 15 to 30 per cent of our daily calorie expenditure. “Setting step goals can be useful,” he says. “An additional 5,000 steps per day can lead to an additional 350-450 calories burned without any formal exercise. But, pretty much the only thing we can do to improve how many calories our body burns at rest is to increase muscle mass. This can be achieved with regular resistance training, a high-protein diet and a slight calorie surplus.”
Dr. Nye agrees with Cox that exercise is key, pointing to evidence that high-intensity training has been linked with improved metabolism in the short period following the activity. “Most people are not consciously aware of their daily calories ingested, so I always suggest people take a few days to understand their intake vs. activity,” says Dr. Nye. “Your metabolism won't slow down if you overeat (it will if you undereat), but your fat deposition will increase.”
There are definitely some solid takeaways there, but my diet isn’t terrible, and if anything, it’s gotten better in recent years. Which leads me to think lifestyle factors might also be playing a part —especially as I now wake up at 3 a.m. thinking about emails on a nightly basis.
“Sleep is a hugely underrated metabolic tool,” says Dr. Lakhani. “Poor sleep lowers testosterone, increases cortisol, and interferes with appetite-regulating hormones like leptin and ghrelin—all of which make it harder to maintain a healthy weight.”
Ironically, all of the cortisol-spiking coffees I down to help me blast through the work I’m so stressed about are also making things worse. “If you’re chronically stressed, your body’s stress hormone—cortisol—stays elevated, and that can signal your body to store fat, particularly around the abdomen,” says Dr. Lakhani. “High cortisol can also interfere with thyroid function and suppress your metabolic rate.”
According to Dr. Bains, stress is “likely the most important factor as it also impacts sleep and directly impacts hormone production.”
Which hits me like an arrow to the heart.
“We all need to figure out a way to manage our stress better. Meditation might work for some but may cause even more stress for others, especially when they struggle to quiet their mind and it feels like they are failing at it,” she says.
The solution to your stress might be trial and error, playing around with everything from breathwork, to cold plunges or showers, morning light, grounding, and actual rest days where there is nothing planned. In other words, slowing down might actually help you hit your goals.
What’s a brief, metabolism-boosting workout I can try?
“Focus on strength-building workouts,” Dr. Bains advises. “These specific exercises work because they recruit multiple large muscle groups at once, hence causing more muscle activation and better hormonal response. Moves like squats, rows and presses mimic natural movement patterns, build core stability and are far more efficient for building strength and muscle than isolated or machine-based exercises.” He adds to get Zone 2 training in on rest days as well.
Try two rounds of this 20 minute workout with minimal rest between exercises:
- Goblet squats: 45 secs
- Push-ups or dumbbell press: 45 secs
- Bent-over rows: 45 secs
- Jump lunges or step-back lunges: 45 secs
- Plank to push-up: 45 secs
- Rest: 60 secs
For Round two: Increase reps or intensity. Finish with 2 minutes of slow, mindful breathing.
What else do I need to remember?
Crucially, you can dial in all of the above, but you can’t fight genetics. As Dr. Nye explains, “this could all be predetermined and in essence you might be fighting a losing battle before you even begin.”
We’re all going to age, and things will slow down, but that doesn’t mean we have to just give in, does it? “It’s not about doing more, it’s about doing it better,” says Dr. Bains. “In your 30s and beyond, quality beats quantity. Fewer, smarter workouts with proper recovery will get you further than trying to train like you did in your 20s.”
For example, swap back-to-back daily HIIT sessions for three full-body strength workouts with intentional progression and rest days. “It’s often about doing things more intentionally,” agrees personal trainer Penny Weston. “It’s also about redefining success and focusing on energy, strength, mobility and mental clarity, rather than just aesthetics.”
Crucially, Dr. Bains wants you to remember that things change, but not necessarily for the worse. “This isn’t the end of your peak,” she says. “It’s just the start of a new phase.”
This story originally appeared in British GQ.