(P15-046-24) Association of BMI With Accuracy of Estimating Calorie Content of Food: Dietetic vs. Non-dietetic Professionals

Objectives: The US government guidance for weight loss provides a personalized estimate of daily calorie intake, some examples of portions from food groups, and instructions to adjust calorie intake by monitoring body weight (United States Department of Agriculture (USDA), MyPlate Plan, Dietary Guidelines for Americans 2020-2025 (DGA)). In individuals with high Body Mass Index (BMI), following this guidance for weight loss requires knowledge of the calorie value of foods. Hence, we determined the accuracy of the perceived calorie content of common foods among people with formal training in dietetics (DP) and people without such training (NDP) and determined its association with their BMI.

Methods: NDP (n=59) and DP (n=23) participants (18-81 y) completed a questionnaire to estimate the calories for a list of individual common foods or food components. Questionnaire data was collected by the research team at health fairs, symposiums, and professional conferences.  Accuracy of calorie value for a food was determined as within ± 20% of the actual value. We used generalized linear mixed models, specifically logistic regression with a random effect, to analyze accuracy as a function of body mass index. All analyses were performed using R studio (1.4.1717), running R (4.1.0).

Results: The odds of being correct significantly decreased by 3-4% per unit increase of BMI when NDP were asked knowledge-based questions about calories in foods (p < 0.01; e.g., how many calories in a gram of fat?) or when asked to estimate the caloric content of simple foods (p < 0.01; e.g., how many calories in a tablespoon of olive oil?). There was no significant relationship between accuracy and BMI among dietetic professionals.

Conclusions: USDA and DGA recommendations for weight loss seem to assume knowledge of the calorie value of foods by lay-people. However, NDP individuals with higher BMI, who are more likely to need weight loss advice, are less accurate at estimating calories and, hence, less likely to succeed in weight loss efforts. Weight loss guidance with specific structured meal plans may be needed when working with clients not formally trained in nutrition.

Funding Sources: This study was partly funded by a grant from the Paso del Norte Health Foundation.