The Bottom Line: Your body does not require dietary carbohydrates to survive or function. Carbohydrate is not an essential nutrient – your liver produces glucose from fat and protein through a process called gluconeogenesis. The brain runs well on ketones. For most men, removing the bulk of dietary carbs lowers insulin, burns stored fat, and eliminates the energy crashes that come with carb dependence.
I hear this constantly. “Andre, I’ve been cutting fat, watching what I eat, exercising consistently – so why haven’t I lost weight?”
The question assumes the problem is effort. Most of the time it isn’t. It’s the advice they were following.
Carbohydrate is the only macronutrient the body does not require from food.
Protein is essential. Without it, muscle and tissue break down. Fat is essential. Without it, hormones fail and fat-soluble vitamins cannot be absorbed. Carbohydrate? Your liver makes glucose on demand from fat and protein. It has done this for as long as humans have existed. The process is called gluconeogenesis, and it works efficiently without you eating a single gram of carbohydrate.
That is not a fringe position. It is established biochemistry. The National Academies of Sciences set the dietary reference intake for carbohydrate at zero grams per day on the basis that there is no minimum requirement, provided fat and protein are adequate. [Ref 6]
Yet you have probably been told, more than once, that carbs are your body’s preferred fuel. That your brain needs glucose to function. That cutting carbs will leave you foggy, flat, and unable to perform. None of that holds up once you look at what actually happens when carbohydrate intake drops.
Does your brain actually need carbohydrates to function?
No. But here is the distinction most people miss: the brain needs glucose, but it does not need you to eat carbohydrates to get it.
When carbohydrate intake is low, the liver produces glucose through gluconeogenesis, converting amino acids and glycerol into what your brain and red blood cells need. The liver also produces ketone bodies from fat. Ketones cross the blood-brain barrier and are used directly as fuel.
I’ve lost count of the number of men who’ve told me they couldn’t function without oats at breakfast. Two weeks later they’re asking why they haven’t had their usual afternoon crash.
After a period of adaptation, the brain runs largely on ketones, and the demand for glucose drops accordingly. A 2024 review in npj Metabolic Health and Disease found that ketone bodies preserve cognitive function and show neuroprotective effects in multiple metabolic conditions. [Ref 12] During starvation, wartime rationing, or carbohydrate restriction, human brains function. Thinking does not stop when bread stops.
Your brain being uniquely carbohydrate-dependent is a product of how most people have eaten for the past fifty years, not how the brain is designed. The afternoon crash that feels normal is not normal. It is what happens when blood glucose spikes, insulin surges, and glucose crashes in a cycle driven entirely by dietary carbohydrate.
Why does low-carb nutrition stabilise energy better than a high-carb diet?
When you eat carbohydrate, blood glucose rises. Insulin is released to drive glucose into cells. Glucose drops. Energy drops. You eat again. The cycle repeats.
That’s not stable energy. That’s a dependency loop.
If you’re reaching for another coffee at 3pm every day, that’s not because you’re undisciplined. It’s because your body has become very good at burning sugar and very poor at burning fat. Fix the fuel source and the crash goes away – not managed, gone.
Roger Gray is a CEO based in New Zealand. Three months ago he was exercising regularly and nothing was shifting. Seven kilograms later, his words: “No craving or snacking between meals. No mid afternoon energy slump. All gone.” He did not change how much he exercised. He changed what he ate.
A 2015 Cell study with 800 participants showed that individuals eating identical carbohydrate meals produced dramatically different blood glucose responses. [Ref 1] A 2023 Frontiers in Nutrition study found substantial within-person variability in glucose responses even under controlled conditions. [Ref 2] The GI system – the dietetic industry’s proposed solution to carbohydrate variability – was found to be too imprecise to reliably predict individual energy patterns. [Ref 3]
If you want stable energy, you need to break the cycle, not optimise it. Real food that does not spike insulin – meat, eggs, fish, butter, olive oil, and non-starchy vegetables – produces satiety and calm, not highs and crashes. Once fat-adapted, your body runs on a fuel source that is almost inexhaustible. The average lean man carries around 100,000 calories of stored body fat. He carries, at most, 2,000 calories of glycogen. The math speaks for itself.
Is carbohydrate actually an essential macronutrient?
No. Dietary carbohydrate is non-essential. Fat and protein are essential macronutrients. Carbohydrate is not. [Ref 6]
This is not a low-carb talking point. It is published nutritional science. The body requires dietary fat for hormone production, cell membrane integrity, and fat-soluble vitamin absorption. It requires dietary protein for tissue repair, enzyme production, and immune function. It requires zero grams of dietary carbohydrate, because the liver manufactures glucose whenever it is needed.
Traditional cultures provide consistent historical evidence. The Inuit of northern Canada, the Maasai of East Africa, and Mongolian herders have thrived for centuries on high-fat, animal-based diets with minimal or no grain consumption. Their metabolic health, documented in early twentieth century anthropological studies, was markedly better than the grain-dependent populations that colonised their regions.
The current assumption that carbohydrate is the dietary foundation is not ancient wisdom. It is a modern policy position, built in large part during the 1970s and 1980s on flawed epidemiological data, and reinforced by food industry funding. Gary Taubes documents this history in Why We Get Fat. Tim Noakes dismantled it with his own clinical and research career after decades of recommending carbohydrate loading. The science moved. The policy has not.
The men I work with are rarely eating badly because they don’t know better. They’re eating badly because their professional lives make it the path of least resistance. Client dinners, business travel, conference drinks, seventy-hour weeks. The food environment works against them at every turn. Nathan Cannon told me that if I’d asked him before we started whether he ate well, he would have said yes – clean ninety percent of the time, home cooked meals, no processed food. He lost 10.6 kilograms in twelve weeks. The foods most men consider healthy – wholegrain bread, low-fat yoghurt, protein bars – are often precisely the problem.
Most men I work with do not have a willpower problem with carbohydrates. They have a dependency. Rice with dinner, pasta at weekends, beer after a hard week – these are cultural and habitual, baked in over decades. That is not weakness. That is what a dependency looks like. One client recently told me he hadn’t realised how often he thought about food until he stopped chasing his next carb hit. The question is not whether you can restrict carbs. It is whether you are willing to switch fuel sources. The physiology makes it easier than you expect once the first few weeks are behind you. It is not restriction. It is a different engine.
How long does fat adaptation take, and what happens during it?
Fat adaptation is the process by which your body transitions from using glucose as its primary fuel to using fat and ketones. For most men, fat adaptation takes four to eight weeks of consistently low carbohydrate intake – typically under 50 grams a day.
The first week or two can feel rough. Fatigue, headaches, mild brain fog. Most men think they’ve broken themselves. They haven’t. They’re asking their body to run on a fuel source it hasn’t relied on for years. Electrolyte depletion – particularly sodium, potassium, and magnesium – accounts for most of these symptoms. Increasing salt intake and eating adequate fat resolves them quickly.
After adaptation, the shift is not subtle. A 2016 study in Metabolism found that keto-adapted ultra-endurance runners maintained similar muscle glycogen utilization to high-carb athletes while achieving 2.3-fold higher peak fat oxidation rates. [Ref 7] They were not impaired. They were metabolically more flexible.
A 2025 systematic review in Cureus found that LCHF-adapted athletes maintained equal performance in long-duration aerobic events, with fat oxidation rates reaching approximately 1.5 grams per minute. [Ref 8] These athletes were not running on glucose. They were running on fat – and performing.
I have been eating this way for fifteen years. My training load runs at fifteen or more hours per week for half-Ironman distances and marathons. My performance has improved, not declined. I am faster now at 56 than I was at 48. When I followed mainstream high-carb advice, I was heavier, inflamed, and hungry. Six years on LCHF: 64 to 66 kilograms, no inflammation, consistent energy throughout the day. That is not anecdote. That is physiology operating as designed.
Is low-carb eating safe for men with type 2 diabetes or on medication?
This is the question that matters most for many of the men I work with, and the answer requires care.
The short version: carbohydrate restriction is the most direct dietary intervention for type 2 diabetes because it directly reduces blood glucose load and lowers the insulin demand that drives the condition. But if you are taking medication for diabetes, blood pressure, or cholesterol, you must work with your GP before making changes. Medication doses may need to be reduced as markers improve, and that process requires medical supervision.
The evidence is substantial. A 2021 Frontiers in Endocrinology narrative review found low-carb approaches were as effective as, or superior to, other dietary strategies for managing the condition. [Ref 11] The five-year Virta Health trial showed that nutritional ketosis produces durable diabetes remission. One in five participants achieved full remission at five years, with sustained improvements in weight, triglycerides, and HDL cholesterol. [Ref 5]
Geoff Steer had been diabetic for several years when his doctor started growing increasingly concerned about the trend. He had known me for thirty years and watched the results I was getting with other men before finally reaching out. He lost 9 kilograms by focusing on what he ate, not how much. His blood sugar levels fell to a point where his doctor’s response was: “Keep doing what you are doing.”
Bill Sowry is a consultant. In four months, he lost 15 kilograms. Blood pressure back to normal. Resting heart rate down. Off medications. His GP was surprised. Bill’s take: “Andre helps you to understand how to make this sustainable.”
If you are on medication and considering this approach, do not self-manage. Take the evidence to your doctor. Insist on monitoring. The goal is to improve your markers to the point where medication becomes unnecessary, not to stop medication before your body is ready.
Does low-carb raise cholesterol, and is that a problem?
This is where many men hit resistance from their GP, and it deserves a direct answer.
Low-carb, high-fat eating typically raises total cholesterol and LDL in some individuals. In many cases, the LDL particle composition shifts toward larger, less atherogenic particles. Triglycerides drop. HDL rises. These changes are an improvement in cardiovascular risk profile, not a deterioration.
Here’s the problem. Most GPs measure total LDL and flag it without assessing the full lipid panel. I have sat with clients who were told to stop their low-carb approach because their LDL had risen – despite the fact that their triglycerides had halved and their HDL was the best it had ever been. A high total LDL reading on its own, in the context of low triglycerides and high HDL, is a completely different risk picture from elevated LDL combined with high triglycerides and low HDL. That combination is what a high-carbohydrate diet produces.
A 2025 meta-analysis of 174 randomised controlled trials found that carbohydrate-restricted diets improved cardiovascular health and body composition, with benefits increasing over longer timeframes. [Ref 4] A 2022 Frontiers in Nutrition meta-analysis found low-carb diets lowered triglycerides and improved metabolic markers. [Ref 10]
Do not abandon a working approach without investigating the full picture. Ask for a complete lipid panel – triglycerides and HDL, not just total LDL. Ask about particle size if you can get it. The triglyceride-to-HDL ratio is a more useful cardiovascular risk indicator than total LDL alone, and it almost always improves on low-carb.
I am not asking you to override your doctor. I am asking you to ask better questions.
What happens to energy and performance when you stop eating carbs?
For the first two to four weeks, performance may dip. This is not permanent. It is adaptation. Once the metabolic machinery shifts to fat as the primary fuel, performance in endurance activities typically returns to baseline and, for many men, improves.
Mark Purcell came to me after spending years on the bariatric surgery waiting list. He had known me through the military and figured it was worth trying before going under the knife. He lost 18 kilograms in twelve weeks on a low-carb approach. He never had the surgery. His energy improved. He was not flat or depleted. He was no longer carrying the metabolic burden of insulin-driven fat storage.
Martin Griffiths is an engineer and Executive Director in Melbourne. Before working with me, he spent three months at the gym plus calorie counting and lost three kilograms. Twelve weeks on my approach: twelve kilograms. His assessment: “I’ve probably added at least a decade to my life.”
The men who come to me having done everything the mainstream recommends – eating low-fat, counting calories, grinding through cardio – and getting nowhere, are not failures. The model failed them. Training harder never fixed it. The food was the missing piece. You cannot out-train a fuel source your body cannot use properly.
I have seen the same across 895 men over fifteen years.
Why does mainstream dietetics still recommend carbohydrates as a dietary foundation?
Because institutions change slowly, and the food industry has a financial interest in them not changing at all.
The dietary guidelines that placed carbohydrate at the foundation of the food pyramid were built on observational epidemiology, not controlled experiments, and they were heavily influenced by grain industry lobbying. The famous Ancel Keys study that implicated saturated fat in heart disease selectively omitted countries that did not fit the hypothesis. This is documented history, not conspiracy.
The science has moved. Jason Fung’s clinical work on insulin-driven obesity, Stephen Phinney’s decades of research on fat adaptation and human performance, and Tim Noakes’s career-redefining journey from carbohydrate loading advocate to LCHF champion – these are not fringe voices. They are credentialed researchers and clinicians whose work withstands scrutiny.
What I call conventional stupidity is not stupidity in the people following the advice. It is stupidity in the system that keeps producing the same advice despite the evidence. You followed the guidelines. The guidelines failed you. That is not your fault. But staying on a model that has already failed you is a choice you are making now.
What should men over 40 actually eat?
Eat real food. Prioritise protein and fat. Remove refined carbohydrates and sugar. Keep non-starchy vegetables. That is the foundation.
In practice for most men I work with: meat, fish, eggs, butter, olive oil, cheese, nuts, and above-ground vegetables form the core of the diet. Grains, bread, pasta, rice, and sugar are removed or drastically reduced.
Cut alcohol back – not for moral reasons, but because your body clears it first. It treats alcohol as a toxin. While that’s happening, fat burning stops entirely. For men who drink regularly and cannot shift weight despite eating well and training consistently, this is often the piece that explains everything. The mechanism is not complicated. It is just not talked about.
Fix the food and hunger regulates itself. The appestat – the body’s built-in hunger control mechanism – functions properly when insulin is stable. When it’s running on glucose spikes all day, it doesn’t. Most men report better sleep within the first two to four weeks as well – not as a side effect, but as a direct consequence of stable blood sugar through the night.
The kitchen is where weight loss happens. Not the gym.
If you are still hungry two hours after eating, your food is wrong. If you are crashing at 3pm and reaching for coffee, your food is wrong. If you are training consistently and not losing weight, your food is wrong.
Fixing the food fixes the problem. Everything else is a finishing touch.
If you want to be the man your kids can still keep up with at sixty – active, lean, sharp – what you eat in the next twelve weeks matters more than any other health decision you will make this year.
The free carb calculator will show you roughly where you are now. It is a starting point, not a prescription – but for most men the number is instructive.
If what I have described here matches your situation, the next step is a thirty-minute conversation. It costs nothing. Book a call here
Find out exactly what's keeping you stuck.
Frequently asked questions
Do we really need to eat carbs to survive?
No. Carbohydrate is the only macronutrient the body does not require from food. The liver produces glucose through gluconeogenesis, converting fat and protein into glucose whenever it is needed. The dietary reference intake for carbohydrate is zero, provided fat and protein are adequate. The body runs efficiently on fat and ketones without dietary carbohydrate.
Do carbs give you energy, or is fat a better fuel source?
Carbohydrates produce glucose, which provides energy, but they also trigger insulin surges and crashes that create the energy instability most people treat as normal. Fat is a more stable fuel source, particularly for men with substantial stored body fat. Once fat-adapted, most men report steadier energy throughout the day – no spikes, no crashes, no 3pm reach for coffee.
Can the brain function without carbohydrates?
Yes. The brain uses both glucose and ketones as fuel. When carbohydrate intake is low, the liver produces glucose via gluconeogenesis and ketones from fat breakdown. The brain adapts to run largely on ketones. I regularly hear from men who were convinced they’d be mentally useless without carbs – and who report clearer, more consistent thinking after fat adaptation than they had before.
Is it safe to cut carbs if you have type 2 diabetes or are on medication?
The evidence for carbohydrate restriction in type 2 diabetes is strong, including the five-year Virta Health trial showing durable remission with nutritional ketosis. However, if you are on Metformin, insulin, or other diabetes medication, work with your GP before making changes. Blood glucose will drop as carbohydrate intake drops, and medication doses may need to be reduced under medical supervision to avoid hypoglycaemia.
Does a low-carb diet raise cholesterol and increase heart disease risk?
Low-carb eating typically raises total LDL in some men while lowering triglycerides and raising HDL. The triglyceride-to-HDL ratio is a stronger cardiovascular risk indicator than total LDL alone, and this ratio typically improves on low-carb. A 2025 meta-analysis of 174 randomised controlled trials found carbohydrate-restricted diets improved cardiovascular markers. Request a full lipid panel before drawing conclusions from a total LDL figure.
How long does it take to adapt to eating low-carb?
Most men take four to eight weeks. The first one to two weeks can feel rough – fatigue, headaches, brain fog. Most guys assume something has gone wrong. Nothing has gone wrong. Your body is switching fuel systems. Adequate salt intake and sufficient dietary fat clear the symptoms quickly. After adaptation, energy, performance, and hunger regulation all improve.
Studies and resources
[1] Zeevi, D., Korem, T., Zmora, N., et al. (2015). Personalized nutrition by prediction of glycemic responses. Cell, 163(5), 1079-1094. https://doi.org/10.1016/j.cell.2015.11.001
[2] Daanje, M., Siebelink, E., Vrieling, F., et al. (2023). Are postprandial glucose responses sufficiently person-specific to use in personalized dietary advice? Design of the RepEAT study. Frontiers in Nutrition, 10. https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2023.1281978/full
[3] Kaur, B., Koh, M., Ponnalagu, S., & Henry, C. J. (2020). Postprandial blood glucose response: does the glycaemic index (GI) value matter even in the low GI range? Nutrition & Diabetes, 10, Article 15. https://www.nature.com/articles/s41387-020-0118-5
[4] Meta-analysis of carbohydrate-restricted diets on cardiovascular and body composition outcomes (2025). https://ajcn.nutrition.org/article/S0002-9165(25)00528-3/fulltext
[5] McKenzie, A. L., Athinarayanan, S. J., et al. (2024). 5-Year effects of a novel continuous remote care model with carbohydrate-restricted nutrition therapy including nutritional ketosis in type 2 diabetes. Diabetes Research and Clinical Practice, 217, 111898. https://doi.org/10.1016/j.diabres.2024.111898
[6] Trumbo, P., Schlicker, S., Yates, A. A., & Poos, M. (2002). Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein and amino acids. Journal of the American Dietetic Association, 102(11), 1621-1630. https://doi.org/10.1016/S0002-8223(02)90346-9
[7] Volek, J. S., et al. (2016). Metabolic characteristics of keto-adapted ultra-endurance runners. Metabolism, 65(3), 100-110. https://pubmed.ncbi.nlm.nih.gov/26892521/
[8] Sultan ZH, Speelman D. (2025). A systematic review of the effects of low-carbohydrate diet on athletic physical performance parameters. Cureus, 17(2):e79166. https://doi.org/10.7759/cureus.79166
[9] Chiarioni G, et al. (2023). The effect of polyphenols, minerals, fibers, and fruits on irritable bowel syndrome: A systematic review. Nutrients, 15(18):4070. https://doi.org/10.3390/nu15184070
[10] Lei L, Huang J, et al. (2022). Effects of low-carb vs low-fat diets on metabolic risk factors. Frontiers in Nutrition. https://www.frontiersin.org/journals/nutrition
[11] Wheatley SD, et al. (2021). Low carbohydrate dietary approaches for people with Type 2 diabetes. Frontiers in Endocrinology. https://www.frontiersin.org/research-topics/16762/carbohydrate-restricted-nutrition-and-diabetes-mellitus/magazine
[12] Fulghum K, et al. (2024). Ketone body metabolism and cardiometabolic implications for cognitive health. npj Metabolic Health and Disease. https://pmc.ncbi.nlm.nih.gov/articles/PMC11908690/
