Recently, a gym member asked me what I thought about an article titled “5 Reasons Carbs Are Not the Enemy” written by a dietitian and published on the Goodlife Health Clubs website where I used to teach.
Aside from agreeing with the first two lines, I disagreed with nearly everything else. It ignored basic metabolism, misrepresented low-carb nutrition, and overlooked modern science.
So let’s look at what the evidence and experience, actually show.
Carbs and “Balanced Energy”: Still a Myth.
The author claimed carbohydrates “help balance your energy levels,” saying that low-GI foods give a steady stream of energy for two hours or more.
That sounds nice, but biology doesn’t agree.A landmark 2015 Cell study involving 800 people showed that individuals eating identical carb-based meals produced dramatically different blood-glucose responses, highlighting why universal dietary recommendations often fail [Ref 1].
A 2023 Frontiers in Nutrition study questioned whether individual glucose responses are consistent enough for personalized dietary advice, demonstrating substantial within-person variability under controlled conditions [Ref 2]. Meanwhile, a 2020 study in Nutrition & Diabetes showed that even foods within the same low-GI category (GI values of 24 vs. 54) produce markedly different metabolic responses, suggesting GI classifications are too broad to reliably predict individual energy patterns [Ref 3].
If you truly want stable energy, focus on foods that don’t spike insulin: meat, eggs, fish, butter, olive oil, and low-carb vegetables. These promote satiety and calm, not highs and crashes.
See my article Calories In, Calories Out for how energy balance really works.
Low-Carb Diets Are Sustainable, and Proven
The same article claimed that “very few people can maintain low-carb beyond 3–6 months.” That’s outdated thinking.
A comprehensive 2025 meta-analysis of 174 randomized controlled trials found that carbohydrate-restricted diets significantly improved cardiovascular health and body composition, with benefits increasing over longer timeframes [Ref 4].
The five-year Virta Health trial demonstrated durable remission of type-2 diabetes with nutritional ketosis [Ref 5]. One in five participants achieved full diabetes remission at five years, with sustained improvements in weight, triglycerides, and HDL cholesterol.
Sami Inkinen 2011 Ironman World Championships
I’ve eaten this way for fourteen years (as of 2025). No deprivation, no brain fog, no cravings. Once you become fat-adapted, your body makes ketones—a clean, stable fuel for both brain and muscle.
Learn more in Fat Adaptation for Endurance Performance.
Carbohydrates Are Not Essential Nutrients
Basic biochemistry tells us that carbohydrates is non-essential, unlike fat and protein [Ref 6].
Your liver easily makes glucose through gluconeogenesis when you need it.
A 2016 study in Metabolism found that keto-adapted ultra-endurance athletes maintained similar muscle glycogen utilization and repletion patterns to high-carb athletes, while achieving 2.3-fold higher peak fat oxidation rates, demonstrating that well-formulated low-carb diets can support endurance performance through enhanced metabolic flexibility [Ref 7].
Traditional cultures, the Inuit, Maasai, and Mongolian herders, thrived for centuries on high-fat, low-carb diets. Our modern grain-based society? Fatigued, inflamed, diabetic.
Endurance: Why Fat-Adapted Athletes Are Winning
Fat-adapted endurance athletes are changing the playbook.
A 2025 systematic review in Cureus found that LCHF-adapted athletes maintained equal performance in long-duration endurance events, with fat oxidation rates reaching approximately 1.5 g/min and glycogen-sparing effects [Ref 8]. While LCHF diets didn’t consistently improve performance, they also didn’t impair it in most aerobic tests lasting 10km or longer.
They burned fat efficiently, spared glycogen, and recovered faster.
In my own training, 15 hours per week for half-Ironman and marathons, my performance has improved. I run faster now at 56 than I did at 48.
When I followed mainstream “eat more carbs” advice, I was heavier, injured, and hungry.
Six years on LCHF: 64–66 kg, no inflammation, consistent energy.
That’s not hype. That’s physiology working as intended.
Fiber, Gut Health, and the Myth of “More Is Better”
Fiber and IBS is nuanced: while some research shows soluble fiber supplementation can reduce bloating [Ref 9], many people with IBS find relief by reducing fermentable fibers (FODMAPs). Individual tolerance varies—experiment to find what works for your gut. [Ref 9].
Humans don’t digest fiber; our gut microbes do. For many, that fermentation causes gas, cramps, or nutrient malabsorption.
Try two weeks with lower fiber from grains and legumes and notice the difference.
You can still nourish your microbiome with non-starchy vegetables and fermented foods, without the gut chaos.
Do High-Carb Diets Make You Live Longer?
The “carbs = longevity” claim comes from weak association studies, not controlled experiments.
Correlation isn’t causation.
Modern randomised trials show the opposite trend:
- 2022 Frontiers in Nutrition meta-analysis found low-carb diets lowered triglycerides and improved metabolic markers [Ref 10].
- 2021 Frontiers in Endocrinology narrative review found low-carb approaches are as effective as, or superior to, other dietary approaches for managing Type 2 diabetes [Ref 11]..
Low-carb isn’t trendy; it’s a return to pre-insulin medical nutrition therapy.
For deeper reading, see Gary Taubes’ Why We Get Fat and Nina Teicholz’s The Big Fat Surprise.
The Bigger Issue: Conventional Stupidity
The fitness industry profits from confusion.
It sells you carb-heavy snacks, “energy” gels, and endless HIIT classes while warning that fat will kill you.
That’s what I call conventional stupidity, doing what everyone does, even when it clearly doesn’t work.
If you’re still hungry, tired, and inflamed, your diet isn’t serving you.
Question the dogma. Eat real food. Take ownership of your health.
For mindset support, see Choose Your Mindset.
FAQs
Q: Do we need carbs for brain function?
No. Once fat-adapted, the brain runs beautifully on ketones. Recent neuro-metabolic studies (2024 npj Metabolic Health and Disease) show ketone bodies preserve cognitive function [Ref 12].
Q: Are carbs “bad”?
No, but most people eat excessive refined ones. Vegetables = good; processed grains = trouble.
Q: Will low-carb hurt performance?
Evidence shows equal or better endurance when athletes adapt fully [Ref 8].
Q: Is low-carb safe long-term?
Yes. Multi-year follow-ups confirm improved metabolic health and lower medication use [Ref 4, 5, 11].
Key Insights
- Carbohydrate is not essential; your liver produces glucose.
- Ketones are an efficient, clean fuel for body and brain.
- Long-term low-carb is safe and sustainable.
- Fiber and grains are optional, not mandatory.
- Mainstream advice keeps people dependent; real food builds freedom.
