Researchers in Britain tracked thousands of children at the ages of 3, 4, 7 and 8 1/2. They found that when a 3-year-old ate a lot of fatty, sugary, processed foods, their IQ was lower at the age of 8.
But the scientists didn't find the same correlation in youngsters aged 4 and 7. Doctors note that many other variables come into play at these ages.
The research is published in the Journal of Epidemiology and Community Health.