Mattes claimed he tried to maximize the behavioral effects of artificial food dyes by (1) studying only children already on the Feingold diet, (2) trying to exclude placebo responders, and (3) administering high dosages of coloring. He reported that “evaluations by parents, teachers, and psychiatrists and psychological testing yielded no evidence of a food coloring effect.”
- Their “high dose” of coloring did not even change the color of the cookies from identical cookies without coloring. To reach the maximum of 78 mg coloring per day, 6 cookies were required.
- According to parents involved in the study, some children could not eat all the cookies, so they did not receive even that small dose of coloring.
- Children who have been on the Feingold Diet for a long time may be able to tolerate small or infrequent doses of food dyes or other items “off-diet.”
- Evaluations were not always done 1 1/2 hours after eating a cookie, as reported. See a parent’s letter here. Besides, 1 1/2 hours is probably not sufficient time for a reaction to take place since many children react 2 to 4 hours later and may have been missed.