Every five years, the Dietary Guidelines for Americans are jointly issued and updated by the Department of Agriculture (USDA) and the Department of Health and Human Services (HHS). They exist to help Americans make informed food choices, maintain a healthy weight, and promote overall health. Recent dietary guidelines have focused less on encouraging dietary variety because of concern that it promotes obesity. One NYU Steinhardt researcher finds, however, that it may be premature to conclude that dietary variety has an adverse impact on body weight and that this lack of clarity limits the development of clear national nutrition guidelines.
"What we found is that there is no consistent evidence showing that greater food variety increases the risk of obesity," said Maya Vadiveloo, a doctoral student within NYU Steinhardt's Department of Nutrition, Food Studies, and Public Health.
Vadiveloo's latest research, published in the British Journal of Nutrition, examined the associations between dietary variety and measures of body fatness including the body mass index (BMI), waist and hip circumference, and percentage of body fat. In a comprehensive review of literature spanning nearly 15 years, Vadiveloo and colleagues conclude that while the majority of the studies suggest that dietary variety increases energy intake, the direct correlation to body weight cannot be drawn.
According to Vadiveloo, part of the inconsistency is due to the varying and non -comprehensive techniques used to measure dietary variety.
"The recommendation to 'eat a variety of foods' has historically been a key part of the Dietary Guidelines for Americans because it was associated with better overall health. This is because you need to eat different foods to get all the nutrients you need, as each food and food group supply different nutrients," Vadiveloo explained. "But in order to better understand the relationship between dietary variety and weight, we have to look at the number of different foods consumed, the healthfulness of each food, and the amount of each food consumed in the total diet. In a series of upcoming studies, our research group developed a novel score that incorporates these components in order to better understand the relationship between dietary variety and body weight."
Vadiveloo's study was funded by an American Heart Association (AHA) Predoctoral Fellowship she received in 2011. Under the guidance of her doctoral advisor, Niyati Parekh, Vadiveloo's work will continue to explore factors that influence eating behavior and that have the potential to influence obesity and related chronic diseases.