Reviewed September 2026. Covers the fat-loss, exercise, frequency and diet-setup chapters of both books, plus the online calculator. Added so you don't have to scroll 4b. The "fasting mimicry" claim is biochemically wrong IMO This one won't cost you muscle or fat loss. But if you bought into the idea that RFL days give you the cellular benefits of fasting, you should know the claim doesn't hold. In Chapter 11 he writes: "Fundamentally, my RFL is nothing but a ketogenic diet without the dietary fat. Which means that it generates the same basic physiological shift as with complete fasting." He's half right. RFL does deplete liver glycogen, shift you towards fat oxidation, and produce ketones. That's the metabolic switch. Fine. What it does NOT do is replicate the cellular signalling state of a true fast. The reason: he's telling you to eat 150–220 g of protein on those days. The amino acid leucine — abundant in every lean protein source he recommends — is the most potent known activator of mTORC1. And mTORC1 activation directly suppresses AMPK and shuts down autophagy (Levine & Kroemer, 2019; Alirezaei et al., 2010). Translation: the protein that protects your muscle is the same protein that prevents the cellular cleanup he's claiming you get. You cannot have both simultaneously. Does this matter practically? For his stated goals — fat loss without muscle loss, training support — no. The RFL day works brilliantly for those. But if you were banking on autophagy, mitophagy, or the hormetic stress-response benefits that the fasting literature discusses, an RFL day will not deliver them. You'd need actual amino-acid deprivation for that, which is the opposite of what he prescribes. He also dismisses Longo's Fasting Mimicking Diet as "nonsensical" while running what is functionally a modified fasting-mimicking approach himself — just with the right macronutrient (protein) instead of the wrong ones (carb/fat). The dismissal is ironic and the physiological claim needs a qualifier.

I went digging into "beef protein isolate" powders because things didn't add up. Here is what I found, with sources. "Beef protein" on a UK/EU label names the animal, not the tissue. 🫣 The mandatory nutrition declaration does not include amino acids (Regulation (EU) No 1169/2011) — so the tub alone cannot tell you whether you bought muscle protein or collagen made from hides and bones. Why it matters: collagen contains zero tryptophan and very little leucine. In a randomised trial, whey — but not collagen — stimulated muscle protein synthesis (Oikawa et al., 2020, American Journal of Clinical Nutrition). The fix is one number: hydroxyproline. It is collagen's chemical fingerprint. Muscle has only traces. And you can't spike it away with added aminos. Case in point: one US brand, True Nutrition, publishes its full amino table — 10.2 g hydroxyproline and 3.7 g leucine per 100 g. Collagen-dominant, by the brand's own numbers. One published table settles the question in seconds. Every UK-sold "beef protein" tub I have checked — across the major brands — prints no amino table at all. Not one shows leucine, tryptophan or hydroxyproline. The name changes; the silence doesn't. And the supply chain isn't hiding it: a major trade ingredient sold to supplement makers as "beef protein hydrolysate" is described by its own supplier as "derived from carefully processed bovine bones." To be fair: collagen is a legitimate supplement for joints and tendons — the research supports that use. It is not a muscle-building protein, and it shouldn't be dressed as one. So here's the rule. Ask the brand for the full amino acid table for your exact SKU and batch. Read hydroxyproline first. If they won't show the numbers, treat the tub as unverified — not proven collagen, not proven muscle. No table, no trust.

What is your favoured rest interval between sets. I don’t time between warm up sets, I just use the time it takes to adjust the weights on my dumbbells. I use 2 1/2 minutes on all work sets except for squats and Romanian deadlifts, where I use 3 minutes. I’d be really interested to hear what you do.

I bought some of this whey isolate. They don’t do plain/unflavoured. I bought malted chocolate. If you haven’t got a sweet tooth, look elsewhere. This stuff is so sickly it drew my arse up to my elbow.

I think this topic will apply to several posts. Quick question before you read on: how many different fuels can the human body actually run on? Most people say three. The answer is seven. Drop your guess in the comments, then check yourself. The body follows one rule: it oxidises first whatever it cannot store. That gives you a queue, from first used to last. 1. Alcohol. Zero storage capacity, so the body deals with it immediately, and while it does, everything else waits. In infusion studies, alcohol alone cut fat oxidation by 87%. Add glucose after the alcohol, and fat oxidation drops to almost nothing for 90 minutes. Interesting twist: the liver exports most of alcohol's energy as acetate, which the rest of the body then uses. 2. Ketones. No storage tank either. Made by the liver from fat when glucose runs short — and the liver, remarkably, cannot use the ketones it makes. It lacks the enzyme. They are produced purely for export. In prolonged fasting, they supply up to 60–70% of the brain's energy, the adaptation that stretches survival without food from weeks into months. 3. Carbohydrate and protein — the contested middle. You hold roughly 400–500 g of glycogen, about 6,700 kJ. One hard day. Protein has no storage depot, so every gram used for energy means dismantling working tissue. Disposing of a protein-rich meal also produces the biggest rise in heat output of any fuel — the body literally vents the surplus as warmth. 4. Lactate. Not a waste product — that idea died decades ago. Working muscle exports lactate, and the heart and even the brain take it up and use it as fuel. The catch: it is recycled glucose carbon, so it moves energy around the body without adding any. 5. Short-chain fatty acids. The fuel almost nobody names. You cannot digest fibre — but the bacteria in your colon can, and they ferment it into fuels that supply roughly 10% of your daily energy. The cells lining your gut draw 60–70% of their energy from these. 6. Fat. Last in the queue, biggest tank by a distance: around 15 kg in a typical adult, roughly 565,000 kJ. Stored at 96–98% efficiency. While carbohydrate is abundant, fat oxidation is actively suppressed — a mechanism first described by Randle in 1963. And from a study we verified in full this week: the greatest amount of fat is oxidised at moderate exercise intensity, not at really low or maximal intensity. At 85% effort, fat use is no higher than at 25%. Now the part that reframes everything.