A comprehensive review conducted by Murphy et al. (1998) talks about numerous studies that link poor nutrition and its lasting effects on a child's cognitive development and school performance. Many different research methods were used in these studies including surveys, observations, and the like. Some research studies compared students that ate breakfast and their standardized achievement scores. Other studies looked at a student's problem solving skills, test scores and school attendance rates and additional studies compared sugar consumption and bad behavior (Windsor 1995). In a Yale study, Windsor discovered that within hours after a student consumed the sugar equivalent of two 12-ounce cans of cola on an empty stomach; their bodies released large quantities of adrenaline which can cause anxiety, concentration problems, excitability and shakiness. Some of their measurement devices included brain wave analysis and blood glucose levels.
A researcher named Cartwright conducted an interesting study (Cartwright et. al. 2003) and administered a questionnaire reviewing many variables involved with a student's dietary intake. The survey included measuring a stress score, fruit, vegetable and fatty food intake, snacking, the amount of breakfasts eaten per week and if the child was overweight. Some significant findings shows that over 38% of the sample children shacked in the morning, over 17% of the students had less than 2 breakfasts per week and that 25% of the study group was considered overweight (Cartwright et.al. 2003).