Useful Mind / did not hold up practise daily →
Did not hold up all 15 findings

Sugar makes children hyperactive

Does sugar make children hyperactive? No. The effect is in the parent.

Sugar makes children hyperactive.

What actually happened

Wolraich, Wilson & White meta-analysed 23 controlled trials (JAMA, 1995) and found no effect of sugar on children’s behaviour or cognition. Hoover & Milich (1994) told mothers their sons had been given sugar when the boys had in fact been given a placebo; those mothers rated their sons as markedly more hyperactive, stayed closer to them and criticised them more. The effect turned out to sit in the observer.

Check it yourself: doi.org/10.1001/jama.1995.03530200053037

What to do instead

When a child’s behaviour changes, look at sleep, hunger, time of day and how exciting the room is. And watch that knowing what somebody consumed does not quietly colour what you then see them do.

The laws that do this job properly

Checked and written by Devendra K Jha. Published 2026-09-16. How a grade is decided.

Every law on Useful Mind tells you how strong the evidence behind it is. The ones that failed are kept here rather than quietly deleted, because knowing which advice is wrong saves you as much as knowing which is right.

See the ones that held up