Understanding how diet changes over time, particularly during the period from adolescence to young adulthood when individuals often gain independence, is crucial to supporting healthier dietary practices.

A study by the School of Public Health, recently published in The American Journal of Clinical Nutrition, measured adherence to the USDA’s MyPlate dietary guidelines and dietary changes from adolescence to young adulthood. MyPlate provides a consumer-facing tool to help individuals understand recommended food and beverage intake for children and adults. Measuring adherence to dietary guidelines over time is important because it provides a basis for implementing policies and practices to improve nutrition.

The researchers used data from Project EAT, a longitudinal study gathering health and wellbeing data from a group of people from adolescence into young adulthood. Researchers measured dietary intake from four traditionally under-consumed food groups (i.e., fruits, vegetables, whole grains and dairy) and compared it to MyPlate guidelines. Mean daily servings for each of the four food groups was also compared between early young adulthood (average age 25) and later young adulthood (average age 31) to gain more understanding of dietary trends after the period traditionally studied in college and university settings.

The study found:

• adherence to MyPlate dietary guidelines was low among adolescents and young adults;
• except for dairy intake during adolescence, females generally reported higher adherence to MyPlate guidelines;
• between ages 25 and 31 years old (on average), vegetable intake increased, dairy intake decreased, and fruit intake decreased slightly among men;
• adolescents were more likely to meet MyPlate guidelines for intake of fruit (37 percent for females and 30 percent for males) and dairy (53 percent for females and 61 percent for males) than young adults;
• young adults were more likely to meet MyPlate guidelines for vegetables (19 percent for females and 8 percent for males) and whole grains (23 percent for females and 17 percent for males) than adolescents;
• adolescents who started out in the lower quartiles of intake for each of the food groups generally continued to have somewhat low intake of those same groups during young adulthood, although dietary intake varied substantially across adolescent quartiles.

“This study shows some encouraging trends — dietary intake of vegetables and whole grains is improving as youth age into young adults — but there’s clearly still some work to do,” says Mary Christoph, who led the study while a postdoctoral fellow in the School of Public Health and the Medical School.

Based on her research, Christoph stresses the importance of eating dairy and fruits as adherence to guidelines for these groups decreased with age. She notes that it’s important to eat whole fruit, which may have more fiber than fruit juice. Additionally if individuals choose to not consume dairy products, it is important to ensure that they are obtaining nutrients such as calcium, potassium and Vitamin D in other aspects of their diet.

“Adolescence and young adulthood are critical times to support healthy diets, as dietary practices and habits can last a long time and impact long-term health outcomes,” says Christoph. “Ensuring availability, access and promoting nutritious options through partnerships and policies might work to improve nutrition as adolescents age into young adulthood.”