Abstract

Considering the scope of diets available, research studying the efficacy of these diets is necessary. An increasingly popular form of dieting known as “flexible dieting,” and the most recent dietary guidelines released in 2010, USDA MyPlate, are two dietary plans with insufficient amount of efficacy research via randomized-controlled trials. Therefore, the purpose of this research is to assess the 80/20 diet, a specific form of flexible dieting, and USDA MyPlate in hopes of adding more empirical data to these areas of nutritional studies. This mixed-methods study recruited 29 participants and measured changes in physiological and emotional elements, across a threemonth timeframe. Seventeen participants were randomly assigned to the control (followed MyPlate guidelines 100% of meals), and 12 to the 80/20 group (followed MyPlate recommendations in an 80/20 fashion). Preliminary analysis revealed the control group experienced an approximate 58.8% drop-out rate (n=10), compared with the 80/20 group drop-out rate of 16.67% (n=2). Mixed-model ANOVA analysis of the remaining 17 subjects’ data showed no significant relationship between intervention and changes in physiological or emotional factors for both groups. MyPlate adherence analysis showed similar results among both groups (average control adherence: 19.75 days; average 80/20 adherence: 20.64 days). The post-study questionnaire revealed that “MyPlate issues” was the number one cited aspect that participants struggled with most during the study. These results may indicate that an 80/20 diet is a reasonable dietary plan for the general public due to its flexibility; however MyPlate guidelines are difficult to abide by. This difficulty may have contributed to the low adherence rates for both groups, and consequentially, an insignificant relationship between intervention and changes in physiology and psychosocial factors.

Keywords: Obesity; Diet; Health; Psychosocial factors