Nutrition index

Food, supplements and ergogenic aids, graded by evidence. The honest short version: a balanced diet plus a handful of proven aids does almost everything; most of the supplement shelf sells reassurance.

Start with evaluating supplement claims for how to read the evidence behind anything below: who funded it, how good the studies are, and whether the headline is a real performance gain or just a biomarker. Its companion, the marketing playbook, is about the practice itself: how the industry sells fixes for problems you do not have, and how to spot it. A third, supplement contamination and anti-doping, covers the separate question of safety: how often products carry undeclared banned substances, and what that means for a tested runner.

Well-evidenced (the 95%ers)

• Daily carbohydrate, protein and energy needs — the everyday-diet foundation: fuel scaled to the work, enough protein and total energy
• In-race carbohydrate — dosing by duration, and the 90 g/h trick
• Gut training — training the gut to tolerate high carbohydrate intake
• Carbohydrate loading — for events over 90 minutes
• Pre-race and race-morning fuelling — the last few hours before the gun, rehearsed in training
• Caffeine — the most reliable legal aid
• Dietary nitrate (beetroot juice) — real but modest, fades in elites
• Sodium bicarbonate — for short hard efforts; the “pros use it” case
• Iron — correct a diagnosed deficiency, do not supplement when replete
• Hydration — drink to thirst; overdrinking is the danger
• Protein, supplements and recovery nutrition — total daily intake beats timing
• Recovery nutrition — when rapid refuelling matters, the overstated protein window, and rehydration
• Vitamin D and calcium — correct a deficiency, mainly for bone health
• Creatine — strong for power, mixed for endurance
• Beta-alanine — strong evidence, but for a window that barely overlaps distance running
• Collagen and vitamin C — plausible, low-risk support for tendon, ligament and bone; promising but not yet proven

Dietary strategies (contested)

• Low-carbohydrate and ketogenic diets — raise fat oxidation, but the cleanest trials show worse economy and race performance
• Carbohydrate periodisation (train-low) — fuel to the session to amplify adaptation; loud molecular signal, unreliable performance payoff
• Plant-based running nutrition — vegetarian and vegan diets are neutral for performance when planned; mind B12, iron, omega-3 and creatine

Other substances

• Alcohol and endurance — a dose- and timing-dependent tax on repair, refuelling, rehydration and sleep
• Omega-3 fatty acids — sound general-health nutrient and plausible minor recovery aid, no proven performance benefit
• Menthol — reliably makes hot running feel cooler without cooling the body; a small, inconsistent performance benefit in dry heat
• Tart cherry — a modest, real recovery aid for strength and power, with an antioxidant-blunting caveat that makes timing matter
• Curcumin (turmeric) — a real but modest reduction in muscle soreness, tempered by poor absorption and the antioxidant-blunting caveat

Energy, health and body composition

• Relative Energy Deficiency in Sport (RED-S) — too little fuel for the training done; the root of many problems
• Body composition and weight — the power-to-weight trap and why lighter is not simply faster
• Disordered eating in runners — higher risk in endurance sport; warning signs and duty of care

Poorly evidenced (documented with caveats)

• Nomio (broccoli-sprout shots) — hyped, plausible mechanism, no performance evidence yet
• Ketone esters — expensive, no race-day benefit
• Exogenous lactate — lactate is a real fuel, but eating it has not improved performance and upsets the gut
• Ashwagandha — an adaptogen with a VO₂max signal, but low-quality, industry-linked evidence and real safety footnotes
• HMB (β-hydroxy-β-methylbutyrate) — a leucine metabolite with a split endurance signal and a steadier muscle-damage recovery benefit; emerging, not proven
• BCAAs — plausible mechanism, no delivery
• Magnesium — heavily promoted; real if you are deficient, little on top of an adequate diet, and not a cramp cure
• Electrolytes — oversold; no cramp or hyponatraemia protection, and most runners already get enough sodium
• Antioxidant supplements — may blunt adaptation
• CBD (cannabidiol) — no direct athlete evidence, a poorly regulated market, and a THC doping risk
• Supplements that do not hold up — glutamine, MCT, nitric-oxide products and more