Practices

If you are testing whether a food affects you or your child, the test has to be complete. Among children with suspected sensitivity to artificial colouring, most reacted to as little as 100 mg, so a bit left in is enough to blur the answer.

What usually happens is that a family removes the obvious sources, misses the ones hidden in medicines, sauces and cereals, sees no change, and…

Cutting artificial preservatives out can genuinely help a child who reacts to them, because a child who feels unwell behaves worse. What it does not do is treat the ADHD underneath, which will still be there once they feel better.

Worth being clear with yourself about what you are hoping for, because these diets are expensive and hard to keep up. If your child does have…

Gluten free and dairy free eating is essential in coeliac disease and in a genuine milk allergy. Neither one treats ADHD, and putting a child on them without a reason carries costs of its own.

The cost is not only money and nutrition. It is the birthday party where they cannot have the cake and the lunch table where their food is different…

If you are going to test whether a food matters, work out in advance where the plan will leak. School lunch swaps, a grandparent's biscuit tin, your own memory on a hard week: all of it decides whether the answer means anything.

Change one thing at a time and keep everything else steady, otherwise you cannot tell which change did what. Then be honest about who is running the…