NutriLog Guides
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How we write our guides

Our nutrition guides explain what the evidence says in plain English, so you can make your own decisions. Here's where the facts come from and how we keep them honest.

Where the facts come from

We use sources in this order, and every claim in a guide links to the one it came from (118 sources across the guides so far):

  1. UK health guidance. The NHS, the Scientific Advisory Committee on Nutrition (SACN), NICE and the Department of Health and Social Care, plus UK food law for labels and claims.
  2. Systematic reviews and meta-analyses, which pool many studies, including Cochrane reviews and position stands from bodies like the International Society of Sports Nutrition.
  3. Randomised controlled trials for specific questions, described with their size and limits.
  4. Food composition data from the UK's CoFID (McCance and Widdowson's) and USDA FoodData Central, rounded to typical values.

Where the evidence is mixed or only shows a link rather than cause and effect, we say so.

How guides are written and checked

  • Each guide follows the same shape: a one-line definition, why it matters, how much you need, the best food sources, myths and warning signs, then related guides and references.
  • Figures are checked against the source they cite before publishing, and each guide shows the date it was last updated.
  • We update a guide when UK guidance changes or important new research is published.

Not medical advice

The guides are general information for healthy adults. They aren't a substitute for advice from your GP, a registered dietitian or another health professional, especially if you're pregnant or breastfeeding, under 18, have a medical condition, an eating disorder or take medication.

Affiliate links and the app

  • A few guides suggest a product, such as a vitamin D supplement. Those links may be affiliate links: if you buy, NutriLog may earn a small commission at no extra cost to you. They're always labelled.
  • Products only appear where the guide already explains why you might need them, and any health claim shown is one that's authorised for use in Great Britain.
  • Each guide ends with a link to the NutriLog app, which we make. The guides are free to read either way.