Childhood overweight and obesity rates remain high in the United States, and especially in the state of Oklahoma. The purpose of this study was to determine the effectiveness of a nutrition intervention in changing the food choices and decreasing the weight of children. First-grade students and their families were recruited from rural elementary schools surrounding the Stillwater, Oklahoma area. Subjects were split into two intervention groups that both participated in a nutrition and lifestyle intervention utilizing the Stoplight Diet as a guide for healthy eating choices. BMI was assessed at each wave of the study. Before the intervention, food records were collected for at least two full days on a 24-hour recall sheet. A dietary intervention, called the Stoplight Diet, was taught to each intervention group for 12 consecutive weeks at each child's school. Post-intervention, foods were recorded for two more days. Foods were then coded into three categories: green, yellow and red; green being healthiest, red being least healthy. Complete food records were returned by parents for 61 children. There was an overall significant decrease in red foods, an increase in yellow foods, but no significant change in the consumption of green foods after the intervention. Analyses were run to determine effectiveness of each intervention group in reducing BMI and changing foods consumed, and further, whether gender or parent demographics had any influence on foods consumed and BMI status. Gender, intervention designation, and parent demographics had no significant impact on BMI or food choices. Although the Stoplight Diet was not effective in improving BMI classification of overweight or obese children, there was a significant change in food choices made, which can help to attain a healthier lifestyle for children and lead to long-term positive health outcomes over time