Why Metabolic Health is Mental Health – An Interview with Darren Tebbenham

Darren Tebbenham lectured in sport and exercise psychology before deciding the industry had the problem backward. Eat less, move more, choose low-fat–he questions all of it. Now The Diabetes Coach, he helps people prevent and reverse type 2 diabetes–the point where the familiar cycle of losing weight and regaining it stops being disheartening and becomes a disease getting closer. He has written two books on it and taught his approach to more than 3,000 health professionals across 30+ countries.

Darren Tebbenham, Metabolic & Mental Health Expert

He is equally blunt about corporate wellbeing, apps nobody opens, webinars nobody attends, all of it measured in sign-ups rather than outcomes. His alternative is measurement: more than 160 BodyScans in a single morning at NFU Mutual, then an honest conversation with staff about what their own numbers meant. Here he argues that metabolic health is mental health, and that lasting change starts from the inside out.

Your message is that "metabolic health is mental health." What led you to connect those two ideas so closely?

Watching the same thing happen over and over. Someone changes what they eat, starts lifting, gets their blood sugar steady, and comes back three weeks later saying the fog has lifted and they're not snapping at their kids. Nobody promised them that. It just happens.

I came at it from psychology, so my instinct was always that the mind drove the body. It took me years of coaching to accept the traffic runs both ways, and heavily. Your brain runs on glucose and is exquisitely sensitive to how well you handle it. Mood, focus, resilience, motivation, all downstream of metabolism.

We've built an entire wellbeing industry around mindfulness apps while ignoring that half the workforce is on a blood sugar rollercoaster from 7 am. You cannot think your way out of a physiological problem.

You left academia because you believed knowledge alone rarely changes behaviour. What did the real world teach you that the classroom could not?

That I was answering a question nobody was asking. In a lecture theatre you assume the gap is knowledge. Fill it, and behaviour follows. Then you stand on a gym floor and meet a woman who can tell you the glycaemic index of everything in her cupboard and is heavier than she's ever been. The information wasn't missing. It was never the problem.

What the real world teaches you is that people don't fail on the plan. They fail on Tuesday, when the plan meets a bad night's sleep, a birthday cake, and someone else's crisis. Nobody in academia was studying Tuesday.

You've recently narrowed your focus to diabetes specifically. Why now?

Frustration, if I'm honest. I've spent twenty years watching people lose weight and put it straight back on. For most people, that cycle is disheartening. For someone insulin resistant, it's something else entirely. It's a disease getting closer.

Same failure, completely different stakes. More than one in five UK adults now lives with diabetes or prediabetes. Millions have been handed a leaflet and told to lose a bit of weight by people who genuinely care but have twelve minutes and no mechanism to offer. Meanwhile, I'd been pointing everything I know at people who wanted to look better in a dress.

At some point that becomes indefensible. So the work sits under The Diabetes Coach now, preventing and reversing type 2, not managing it.

Your Inside-Out Transformation framework starts with identity before habits. Why does that order make such a difference?

Because habits built on top of the wrong identity are a rented house. They stand up beautifully until something shakes them.

If you think of yourself as someone who's trying to eat well, every meal is a test you can fail. If you think of yourself as someone who eats well, most meals aren't decisions at all. Same behaviour, completely different load-bearing structure.

It's also why "all-or-nothing" is so destructive. When the plan requires perfection, the first ordinary human moment doesn't dent it, it ends it, because you've relabelled yourself as "off it". Change the identity first and a bad Tuesday is just a bad Tuesday. Everyone starts with habits because habits are teachable and identity feels woolly. It's the wrong way round.

Mental health is often treated separately from physical health. What needs to change in healthcare and workplaces?

In healthcare, an honest conversation about direction of travel. We're superb at treating symptoms and largely uninterested in root cause. Someone gets medication for blood pressure, statins for cholesterol, an antidepressant for mood, three prescriptions for what is very often one underlying problem, and nobody joins the dots.

In workplaces, it's simpler and more fixable, stop measuring wellbeing by sign-ups. Every organisation I meet can tell me how many people downloaded the app. None can tell me whether anyone got healthier.

Measure something real. Then you have a baseline, an obligation and, for the first time, a way of knowing if any of it worked.

After training more than 3,000 health professionals, what separates coaches who create lasting transformation from those who simply share good advice?

The good ones are comfortable being quiet. Average coaches perform expertise, they explain, prescribe, demonstrate how much they know. It feels like value, and it changes nothing. The ones who get results ask better questions and then shut up long enough to hear the answer.

The other difference is what they do with failure. Most coaches treat a missed week as a discipline problem, which lands as blame and makes the next week worse. Good ones treat it as information, something in the design didn't survive contact with this person's actual life. Fix the design, not the person.

BodyScan assessments give people measurable insights. What conversations do those results usually start?

Better ones than I expect, every time. The scale is the crudest instrument in the building, and we've built an entire industry around it. A BodyScan shows what it can't, whether you're carrying muscle or quietly losing it, where the fat actually sits, what your metabolism is doing. Two people at identical weight can have completely different risk.

At NFU Mutual, we ran more than 160 scans in a single morning and then stood up and talked to staff about their own numbers. The room changes when it's personal. Nobody attends a wellbeing webinar, everybody queues to find out what's happening inside their own body.

The conversation shifts from willpower to biology, which is the moment people stop feeling like failures and start moving.

Where do you stand on Mounjaro, Ozempic and the rest?

Neither for nor against. That's between a patient and their prescriber, and I don't prescribe. But I'll be direct about what they are. A glucagon-like peptide 1 (GLP-1) shrinks your appetite. It doesn't change your relationship with food, it doesn't protect your muscle, and it doesn't build a single habit for the day you stop. It's a window, not a fix.

Used alongside the right dietary change and proper resistance training, they can be genuinely transformative. Used instead of changing anything, the weight comes back and often takes muscle with it, so you end up lighter, weaker, and more insulin resistant than when you started.

Ninety days to break the grip of cravings is one thing. A prescription as a permanent substitute for skill is another.

When someone has tried countless diets without lasting success, where do you encourage them to begin?

By letting themselves off the hook, and I mean that practically rather than as comfort. They've been told to eat less and move more. For someone insulin resistant, that's the one instruction that can't work. High insulin physically blocks fat release, so they cut harder, nothing moves, and they conclude the problem is them. It was never willpower. It was a hormone, and nobody told them which one.

So we start with measurement, not motivation. Five markers you can check at home in two minutes: waist against height, what a doctor's already said, whether you're on blood pressure or cholesterol medication, and whether the weight goes down, comes back, and is now stuck. Understanding why it's been happening does more for someone's motivation than any pep talk I've ever given.

You return to the idea that change starts from the inside out. How has that shaped your own life?

It's made me suspicious of my own discipline. I used to think I was a disciplined person. I'm not especially. What I have is an environment and an identity that make the right thing ordinary, and on the occasions I've let those slip, my supposed discipline evaporated exactly like everyone else's.

That's been humbling and useful. It's very hard to lecture someone about willpower once you've watched your own fail under mildly difficult conditions.

What are you building now?

Three things that are really one. The Diabetes Coach, a ten-week online programme combining nutrition coaching, live strength training and the accountability that makes it hold. The first week is free.

Alongside it, my colleague Allison Rumgay runs The Women's Strength Coach, the same programme through the lens of menopause and women's strength, which is a genuinely different physiological problem and deserves its own front door.

Through Gloo Fitness, we take the whole thing into workplaces, scan the workforce, tell them what it means, then give them somewhere to go. Both my books, on the biology and the psychology of weight loss, are free to download here.

If every leader understood one thing about metabolism, mental health and performance, what would it be?

That the mental health, energy and productivity of their people have a physical foundation, and unlike almost everything else on the wellbeing budget, it can be measured.

Scan a hundred employees, and you'll find people who have no idea they're walking towards type 2 diabetes. Not one of them will hear it from a mindfulness app. Measure it. Understand it. Change it. That's the whole job.

Visit my website for more info!

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