Is personalised better?

Quite a few companies and individuals (with and without qualifications…) now sell personalised nutrition (PN) packages, based on your « unique metabolism and needs« . To assess these, they will first sell you kits to measure parameters such as glycemia, vitamin and mineral levels (iron, B12, D etc), hormone levels (in particular thyroid hormones), blood fats (cholesterol, triglycerides…), gut bacteria and even your genetics. They will also ask you to fill in questionnaires about your dietary habits, lifestyle, general health status (are you tired?) and phenotype (body type, skin colour).

Holzapfel & Drabsch (2019)

They will provide you with your results and their interpretation, and issue « tailored » dietary and lifestyle recommendations: eat more of this, less of that, move more. But does the personalised advice outperform general guidelines? NO.

Several studies have shown that PN does not do any better than general public health advice in healthy adults. In particular you can check the Food4Me European study and Food4Me RCT, The Personal Diet Study, Ben-Yacov et al, and even PREDICT 1 Study by Zoe. The magnitude of difference vs general advice is negligible, and linked to changes recommended in the general guidelines. At 6 month follow-up, most differences disappear. No additional benefits are shown with the addition of phenotype and genotype data. Furthermore, some of these studies are flawed: what is effective on an outcome is determined before the intervention, labelled as « personalised », and participants are told to do what we know will work: the benefit was therefore expected to occur.

The actual contribution of PN is negligible and of questionable relevance. If you are healthy, save your money and follow the general dietary guidelines to stay healthy. 😉

For the UK: the Eatwell Guide
Pour la France: Manger Bouger
Per l’Italia: Mangia Sano

If you wish to improve your diet or achieve a specific goal, work with a dietitian who will assess your needs and objectives, provide 1 to 1 coaching and support for lasting change.