Start with the parts that are settled
Nutrition arguments are loud at the edges and quiet in the middle. The middle is where almost all of the benefit is.
Eat enough protein. Eat enough total food to support your training. Get most of your calories from things that are recognisably food. Include plants across a range of colours and types. Drink water when you are thirsty and a bit more when it is hot or you are working hard.
Nobody builds an audience arguing for that, which is why you rarely hear it.
Protein, practically
Protein is the nutrient most active adults underestimate, and the one where a change is most likely to be noticed.
The best available synthesis is a meta-analysis of 49 randomised trials in 1,863 healthy adults doing resistance training. Adding protein produced a small but real advantage over training alone: about 2.5 kg more on one-repetition maximum strength and about 0.3 kg more fat-free mass. The dose-response curve flattened at roughly 1.6 g per kg of body weight per day, with the confidence interval running from 1.0 to 2.2 — so 1.6 g/kg is a reasonable working target and a reasonable place to stop climbing.
Two details are worth carrying. First, the effect is modest; protein makes a training programme somewhat more productive, and does nothing in place of one. Second, the same analysis found the benefit to fat-free mass shrank with increasing age, which is the opposite of how protein supplements are usually marketed to older adults.
Getting the total is easier than it sounds once breakfast contains something other than carbohydrate. Eggs, dairy, fish, meat, tofu, tempeh, legumes, and a protein powder if it makes the arithmetic simpler all count.
The Protein Range Planner turns your weight and activity into a working range and a per-meal target.
Hydration without the theatre
Thirst is a reasonable guide for most people on most days, and the consensus position on endurance events is stronger than that: drink when thirsty.
The reason is exercise-associated hyponatremia, which is caused by drinking more hypotonic fluid than you are losing, combined with a hormonal response that stops you excreting the excess. It is rare, it is dangerous, and it is a drinking problem rather than a sweating problem. Drinking beyond thirst has not been shown to reduce fatigue, cramping, or heat illness, so there is nothing on the other side of the ledger to justify it.
One widespread belief needs correcting. Sodium-containing sports drinks are themselves hypotonic and will not protect you if you overdrink during exercise. Sodium may modestly slow the fall in blood sodium, but it does not prevent hyponatremia. Salt is not an insurance policy against volume.
For ordinary days, drink to thirst and check that urine is pale rather than dark. For hot or long sessions, plan access to fluid rather than a schedule of forced intake.
Supplements, in proportion
A very short list has repeatedly survived testing. Creatine monohydrate is the clearest example for anyone doing resistance training: the International Society of Sports Nutrition’s position stand calls it the most effective ergogenic supplement available for high-intensity exercise capacity and lean body mass, and reports no compelling evidence of harm to kidney function in healthy people, including at doses far above normal use over multi-year follow-up. Typical dosing is 3 to 5 g a day, with an optional loading phase of about 0.3 g/kg/day for five to seven days.
Most of the rest of the shelf is either unnecessary, unsupported, or supported only for people with a deficiency.
Before adding anything, ask what specific outcome you expect, over what timeframe, and how you would know if it were not working. If you cannot answer those, the supplement is a subscription rather than an intervention.
Habits over rules
The diet you can run in a busy week beats the one that requires a calm one. Pick changes that survive travel, deadlines, and family meals: a default breakfast, a handful of meals you can cook without thinking, and a way to eat well at the places you actually go.
When to involve a professional
Nutrition is where self-management most often runs into something that needs a clinician rather than a plan.
- Any prescription medication, before you add a supplement. Ask a pharmacist or your doctor about interactions. This is a five-minute conversation with real downside if skipped.
- Kidney disease, or medication that affects kidney function, before taking creatine. The safety data are reassuring in healthy people; they are not a statement about impaired kidneys.
- Pregnancy or breastfeeding. Requirements change and most supplement evidence excludes you.
- Unintended weight loss, persistent fatigue, or a loss of appetite you cannot explain. That is a diagnostic question first and a nutrition question second.
- A restrictive diet held for months — very low calorie, very low carbohydrate, or excluding a whole food group. A registered dietitian is the right person to check what is missing.
- A relationship with food that has become effortful or distressing, or tracking that has stopped feeling optional. Speak to your doctor.
What the evidence does not show
- That protein supplements do much on their own. The meta-analysis measured protein added to a resistance training programme. Without the training there is nothing for the protein to support.
- That more protein keeps helping. The curve flattened around 1.6 g/kg/day. Higher intakes are not obviously harmful in healthy people, but the trials did not find added benefit.
- That older adults get more out of supplemental protein. In this analysis they got less, and why is not settled — the trials in older participants also tended to use smaller doses.
- That any particular hydration schedule improves performance. Drinking to thirst is the recommendation because overdrinking causes harm, not because a volume has been shown to help.
- That electrolyte products prevent cramp. They do not prevent hyponatremia, and cramp has no settled cause. Sold as a solution, it is a solution to a problem nobody has characterised.
- That most of the supplement shelf does anything. For the large majority of products, there is no controlled human evidence at the dose and duration you would actually take them.