Sugar causes behavioural problems

Probably not. So far there is no substantive scientific evidence that the consumption of sugar is directly associated with behavioural or mood changes. There is anecdotal evidence for children exhibiting mood swings and behavioural changes after eating sugar. One reason for this may be that the pleasure of eating, particularly sugary foods, may improve mood. Also, when a diet contains many sugary foods, there is not the same control over blood sugar levels (glucose) associated with a mixed diet; thus, blood sugar levels may rise and fall more quickly than occurs with a more varied diet.