Your GP called it pre-diabetes and told you to eat less fat and move more. Your last blood panel flagged metabolic syndrome, and the advice was the same. Your mates have the same markers, so the whole thing got filed under “just getting older.”
None of them told you what’s actually driving it. And the advice they gave you, eat less, move more, is the one approach almost guaranteed not to work for a man with insulin resistance trying to lose weight.
Not because energy balance isn’t real. It is. But for a man whose insulin is the problem, a calorie deficit is working on the wrong variable. His hormones decide whether the food he eats gets burned or stored, and right now those hormones are biased hard toward storage. You can run a deficit for months and barely move, then conclude you lack discipline. You don’t. The model you were handed doesn’t account for the thing that’s actually in your way.
The Bottom Line: If you have insulin resistance, weight loss isn’t an arithmetic problem, it’s a hormonal one. Chronically high insulin keeps your body biased toward storing fat, so a calorie deficit alone fights you the whole way and usually stalls. Lower insulin by changing what you eat, not how little, and your body starts releasing stored fat again, often without you counting anything.
What is insulin resistance, and how does it block weight loss in men over 40?
Insulin resistance means your cells have stopped responding efficiently to insulin, so your body produces more and more of it to do the same job. The result is chronically elevated insulin, not because you’re eating more, but because your cells have become less sensitive after years of high-carbohydrate eating.
Insulin is your body’s fat storage hormone. When you eat carbohydrates, blood glucose rises, insulin is released, and your cells are signalled to take up glucose for fuel. That part is normal. The part that matters for weight loss is insulin’s second job: while it’s elevated, it suppresses the release of stored fat. Insulin is the primary brake on fat burning. When that brake is on most of the day, your body strongly favours storing fuel over releasing it.
Most men over 40 carrying excess weight have this to some degree. They don’t know it because no one named it. The GP flags it as pre-diabetes or metabolic syndrome and moves on.
You can still lose fat in a deficit while insulin is high. But you’re fighting the hormonal current the whole way, which is why so many men grind through a deficit for months and watch the scale barely move. Trying to lose weight with chronically elevated insulin is like emptying a bath with the tap running hard. You can bail, but you’re working against the inflow. The calorie model tells you to bail faster. No one’s talking about the tap.
This is the mechanism Jason Fung explains in The Obesity Code: obesity as a hormonal problem, not a calorie one. Two men, same calorie count, one eating mostly carbohydrate and one mostly fat, produce completely different hormonal responses and, over time, completely different body composition. The calorie number tells you nothing about that.
If you want the broader case for why “calories in, calories out” describes the symptom rather than the cause, I’ve laid it out separately here: why calories in, calories out doesn’t work for men over 40. This post is about what to do when insulin resistance specifically is the thing in your way.
Why doesn’t a calorie deficit work when you’re insulin resistant?
Because lowering calories does not, on its own, lower insulin, and insulin is what’s keeping the fat in storage.
Start with the assumption everyone is handed: cut 500 calories a day, lose a pound of fat a week. That’s the 3,500-calorie rule, and it comes from static estimates made on isolated tissue in the 1950s. It has never accurately predicted real-world weight loss in humans. It became the model anyway.
For a man with insulin resistance, it fails in a few ways at once. His insulin is chronically high, so his body resists releasing stored fat regardless of the deficit. He cuts calories, loses some muscle, some water, some energy, and the fat barely shifts. Then the model ignores where the calories come from. A 500-calorie deficit built by cutting fat produces a very different hormonal response than the same deficit built by cutting carbohydrate. The carbohydrate cut lowers insulin directly. The fat cut does almost nothing to it. The calorie model treats these as identical. They are not.
And it forces him into obsessive tracking while ignoring the actual driver. Counting to the gram, logging every meal, running deficits, getting nowhere, and concluding the problem is him. I’ve watched men spend months in that cycle. Nothing was wrong with their effort. They were cutting calories when the thing in their way was insulin.
Why does cutting calories get harder the longer you do it?
Sustained calorie restriction makes itself less effective over time, because the body lowers its resting energy expenditure to defend against the deficit. The cut that worked in week one stops working by week eight.
This is documented. Kevin Hall and colleagues at the NIH have shown that prolonged restriction reduces basal metabolic rate, the calories you burn at rest, as a survival response. The body reads severe restriction as a threat and downregulates energy use to match. (Worth being straight about the science here: Hall’s controlled-feeding work is about this adaptive slowdown. The size of the carbohydrate-insulin effect itself is still argued over in the literature. The practical case rests less on winning that argument and more on what’s repeatable in real men: appetite, energy, and what they can actually sustain.)
In practice it means you have to keep restricting further to keep losing, which triggers a deeper slowdown, which demands more restriction. Most men in this loop were never told the mechanism, so they decide they lack willpower. Their body is just doing what any body does under prolonged restriction: protecting itself. The minute the restriction ends, fat regain accelerates, because the body is now efficient at conserving energy.
Tim Noakes put it plainly: if you have to exercise to regulate your weight, your diet is wrong. The same logic applies to permanent restriction. If you have to stay hungry and under-fuelled to hold your weight, you haven’t fixed the problem. You’ve found a way to suffer through it indefinitely.
Are all calories equal for weight loss?
No. A calorie from bread and a calorie from butter do not produce the same hormonal outcome.
Carbohydrate raises blood glucose and triggers an insulin response. Dietary fat produces almost none. So two meals with an identical calorie count, one built around carbohydrate and one around fat, create completely different hormonal environments. For a man with insulin resistance, that difference is the difference between progress and none. The error in the calorie model isn’t the counting. It’s the assumption that what you eat doesn’t matter as long as the number is right.
How do you actually lose weight with insulin resistance?
Lower insulin. That’s the mechanism, and everything else follows from it.
The most direct way to lower insulin is to cut the foods that spike it highest and most often: processed carbohydrates. Bread, pasta, white rice, breakfast cereal, juice, sugar. These are what keep insulin chronically elevated in most men. Remove them and insulin comes down. As it comes down, the brake on fat release eases, and your body can get at stored fat again.
This is what I use with clients: low-carbohydrate, healthy-fat eating. Not because fat is magic, but because replacing carbohydrate with fat removes the primary insulin driver while keeping energy intake high enough that you’re not starving. The body shifts to burning fat as its main fuel, a state called fat adaptation. Once you’re fat-adapted, the appestat starts to self-regulate. Men eat less without forcing it, because they’re no longer riding the blood-glucose crashes that drive hunger and cravings.
For me now that’s two meals a day. I don’t plan them. I eat when I’m hungry, usually around midday, and I don’t think about food between meals. If you’ve spent years eating five or six times a day to avoid crashing, that sounds implausible. It isn’t. It’s what happens when the hormonal environment is working with you instead of against you.
This is not a tweak to the calorie model. It’s a different model. You stop managing the number and start managing the hormone that decides what the number does.
What if you’ve already tried cutting carbs and it didn’t last?
Then the approach didn’t fail. The structure around it did.
Most men have been here. Low-carb for a few weeks, maybe proper keto for a month or two. The weight came off, then work travel hit, or a holiday, or a brutal quarter, and it came back. Short-term carbohydrate restriction lowers insulin and unlocks fat burning, but if you don’t know how to eat in restaurants, how to handle alcohol, how to travel without blowing up the hormonal environment, the results are temporary. The underlying insulin resistance hasn’t been resolved. The moment restriction ends, the old pattern reasserts.
That’s the difference between a six-week keto stunt and a permanent change in fuel source. The mechanism is the same. Willpower isn’t the answer. The system has to survive a work trip, Christmas, and a bad quarter. If it can’t, it won’t last.
What does losing weight with insulin resistance actually look like?
I ran the wrong model myself for years. I was paying a dietitian $200 an hour and running 70 kilometres a week, and I was still fat. Not slightly overweight. Fat. A Stephen Phinney seminar ended it. For the first time someone explained the actual mechanism. I went home, stopped eating bread, rice and pasta, and within six months I was back to 65 kilos. I’m 60 now, 15% body fat, resting heart rate of 39, and I ran 2.4km in 9:47 earlier this year. I don’t count a calorie. I eat intuitively, because fat adaptation regulates appetite for you.
Pavel, a software engineer from Brisbane, came to me a confirmed sceptic. His starting position: “I thought that the human body works just like any other thermodynamic system. It’s physics, right? Just get into a calorie deficit and your body will be forced to burn fat.” His conclusion after trying it: “Wrong. That approach simply doesn’t work. Not for me anyway.” He lost 8kg in 12 weeks, not by counting more carefully, but by changing the model.
Craig, a 55-year-old retired army officer, had worked with a dietitian for years. His verdict on it: “It was good nutrition, but there was no weight loss.” With my low-carb, healthy-fat approach he went from 105kg to 90kg in four months and improved his blood markers across the board. His words: “It was almost embarrassingly easy.” And Troy came back for a second program after his first round cleared his insulin resistance and took off 14kg in 12 weeks.
None of these men lacked effort. They’d just been pouring it into the calorie count when the lever was insulin.
Why fix insulin instead of counting calories?
Because counting keeps your attention on the one number that was never going to change anything. You can hit your deficit every single day and make no real progress while insulin stays high. You can track every gram perfectly and still wonder why nothing changes.
Ask yourself how long you’ve been at this. Months? Years? If the model worked, it would have worked by now. The question that matters isn’t “how many calories am I eating?” It’s “what is my insulin doing?” Because insulin decides whether the food you eat gets burned or stored, and for a man with insulin resistance the answer has been the same for years: too high, for too long.
Fix the hormonal environment. Lower the carbohydrate, raise the fat, let insulin come down. Once it does, your body starts releasing stored fat the way it’s built to. Not through willpower. Not through a bigger deficit. Because the thing that was braking it has eased off.
This is also why GLP-1 medications like Ozempic tend to rebound when you stop. They suppress appetite, they don’t fix the insulin driver, so when the drug goes the hormonal environment is unchanged and the weight returns. The fix is the same wherever you’re starting: lower insulin, change what you eat, build a way of eating that doesn’t need a drug to manage the hunger your hormones are producing.
If you want to see what your tailored macro numbers look like under a hormonal model rather than a calorie one, start with the free macro calculator. It just takes a couple of minutes
Then, if what’s described here matches your situation and you want to know what it looks like for you specifically, the next step is a conversation. It costs nothing and takes 30 minutes. I don’t take everyone, and the call is where we both work out whether this is a fit.
Frequently Asked Questions
How do you lose weight with insulin resistance?
You lower insulin, which you do by changing what you eat rather than how little. Cutting processed carbohydrates (bread, pasta, rice, cereal, sugar) reduces the primary driver of elevated insulin and lets your body release stored fat again. A low-carbohydrate, healthy-fat approach targets the actual mechanism, where a standard calorie deficit does not.
Can you lose weight in a calorie deficit if you’re insulin resistant?
You can, but it’s much harder than it should be. Chronically high insulin keeps your body biased toward storing fat, so a deficit alone fights the hormonal current and often stalls. Lowering insulin by changing the type of food you eat makes the deficit happen more easily and far less miserably.
What is the best diet for insulin resistance and weight loss in men over 40?
Low-carbohydrate, healthy-fat eating has the most consistent results for men with insulin resistance. It directly reduces the main driver of elevated insulin, processed carbohydrates, and lets the body switch to burning fat as its primary fuel. Appetite then tends to regulate itself, so most men eat less without tracking.
Why isn’t my calorie deficit working?
If you’re in a deficit and not losing weight, elevated insulin is the most likely explanation. While insulin is high your body resists releasing stored fat, so cutting calories further mostly costs you muscle and energy. The fix is to change what you eat to lower insulin, not to cut the calories harder.
How do you know if insulin resistance is stopping your weight loss?
The common signals are a waistline that won’t shift despite real effort, constant hunger and afternoon energy crashes, and blood markers heading the wrong way (rising fasting glucose, a pre-diabetes or metabolic syndrome flag from your GP). A fasting insulin test, not just fasting glucose, gives you the clearest read.
