Is there any special kind of food that children with adhd should avoid?

ADHD food to avoid: Sweets ! and caffeinated drinks [coke, pepsi, mountain dew] that stimulate those kids.

Yes,and no: Some children might have adverse effects with the consumption of sweets, artificial sweeteners, dyes, etc.However adhd symptoms are not usually affected with fad diets in the majority of children.As always discuss individual concerns with your md and avoid making changes based on non scientific information.

Stimulant beverages: Any beverage with stimulants such as coffee, soda, energy drinks or tea can worsen adhd symptoms. Also the consumption of chocolate can worsen adhd symptoms & increase adverse effects from medications. Some adhd kids can absorb 2-phenylethylamine from chocolate. This is a psychoactive monoamine alkaloid that mimics the effect of Cocaine on the brain. See http://www.Ncbi.Nlm.Nih.Gov/pubmed/206912.