Mothers told their sons had sugar rated them more hyperactive, though every boy got a placebo. A 1995 JAMA review of 23 studies found no sugar effect.
In a 1994 experiment, every boy got the same sugar-free placebo. The mothers who were told their son had just had a big dose of sugar rated him as more hyperactive.
The study, by D.W. Hoover and R. Milich, appeared in the Journal of Abnormal Child Psychology. It tested whether the "sugar high" parents report could come from what parents expect to see. Figures from the study abstracts.
The setup
The team recruited 35 boys aged 5 to 7 whose mothers said they were "sugar sensitive." Mother and son pairs were split at random into two groups. One group of mothers was told their son had received a large dose of sugar. The other was told he had a placebo. In fact, all the boys got the placebo, the sweetener aspartame.
Mothers and sons were then videotaped while interacting, and each mother was asked about the visit.
What happened
Mothers in the "sugar" group rated their sons as significantly more hyperactive. On the video, those mothers also stayed physically closer to their sons and showed trends toward criticizing, watching and talking to them more than the other mothers did.
The bigger picture
A year later, a meta-analysis in JAMA, led by M.L. Wolraich at Vanderbilt University, pooled 16 reports covering 23 studies in which children ate a known amount of sugar or a sweetener placebo, with children, parents and staff all kept blind. It looked at 14 kinds of measures. For every one, the 95% confidence interval included zero.
The authors concluded that sugar does not affect the behaviour or thinking of children, and that parents' strong belief may come from expectation and association.
What the studies can't tell you
These are older studies with small samples, and the 1994 test included only boys. The JAMA authors note that a small effect of sugar, or an effect in some children, cannot be ruled out. A night of candy can still mean late bedtimes, excitement and sore teeth.
Sources
Figures from the study abstracts. Trends Today read the PubMed abstracts of both papers.
