What are foods that decrease your iq?

Australian & Scot- tish studies showed that IQ's in 8-year-olds who ate fast-food beginning in toddlerhood were 2 points lower that IQ's of 8-year-olds who ate foods " from scratch". Although adjustments for wealth & socioeconomic status were taken into account, cause-and-effect were not proven, as other factors like parental IQ were not factored in. .