(P13-055-25) Cross-Sectional Associations Between Weight Loss Diets and Diet Quality Among Adults in the Cancer Prevention Study-3

Objectives: A variety of dietary strategies are used for weight loss in the United States, yet diet quality of individuals following such regimens is unclear. This study compares diet quality across adult participants who report following weight loss diets as well as those not following a weight loss diet.

Methods: Participants in the American Cancer Society (ACS) Cancer Prevention Study-3 cohort (N=145,825, data collected in 2015) self-reported if they followed a weight loss diet in the past year and the type of diet; this information was categorized into mutually exclusive weight loss diet type categories: structured weight loss diet program, time-restricted diet, low-carbohydrate diet, high-protein diet, low-fat diet, or other types of weight loss diets. Diet in the past year was assessed using a 191-item food frequency questionnaire; diet quality was estimated using the ACS Diet Score (range: 0-12) and Healthy Eating Index (HEI-2020, range: 0-100).  Analysis of variance was used to compare diet quality scores across weight loss diets and those not reporting weight loss diets.

Results: Almost 20% of participants indicated following a weight loss diet for at least one month in the past year. Of those following a weight loss diet, 34% participated in a weight loss program, 3% followed a time-restricted diet, 23% a low-carbohydrate diet, 12% a high protein diet, 1% a low-fat diet, and 28% followed other types of weight loss diets. Compared to participants who reported no weight loss diet (ACS Diet Score 6.4 ± 0.04, HEI-2020 75.3 ± 0.2), diet quality was higher among participants in all weight loss diet categories (all p< .01) except for those following a high-protein diet, among whom diet quality was lower (p < 0.0001). Diet quality was highest among those following a low-fat diet (ACS Diet Score 7.2 ± 0.2, HEI-2020 78.4 ± 0.7) and lowest among those following a high-protein diet (ACS Diet Score 5.9 ± 0.1, HEI-2020 74.0 ± 0.2).

Conclusions: Diet quality was overall higher among participants who reported following weight loss diets compared to those who did not, though participants following a high-protein diet had the lowest overall diet quality. Further research is needed to investigate intakes of diet index subcomponents that may explain differences in overall diet quality.

Funding Sources: American Cancer Society