Dissertation/Thesis Abstract

Diet Quality and Predictors of Adherence to Popular Diets: Using Data from the Adhering to Dietary Approaches for Personal Taste (ADAPT) Feasibility Survey and Pilot Study
by Karlsen, Micaela, Ph.D., Tufts University, Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy, 2018, 218; 10822072
Abstract (Summary)

Background: Interest in popular diets, such as Paleo, Mediterranean and whole food plant-based (WFPB), continues to grow. However, gaps remain with regard to diet quality and predictors of successful adherence to such diets. Web-based recruitment may be an effective strategy for enrolling followers of popular diets into research studies to fill this gap.

Objectives: (1) To establish an online cohort of popular diet followers using web-based recruitment and survey methodology; (2) to describe characteristics of followers and compare mean BMI across popular diets; (3) to compare targeted nutrient composition of popular diets to current guidelines (MyPlate, DRIs) and determine the degree of adherence to the main principles of the diet in those following their diet >1 year; and (4) to examine psychobiological, cultural, social, economic, and environmental factors that potentially influence adherence across diets.

Methods: In 2015, the ADAPT Feasibility Survey recruited 13,787 self-identified followers of popular diets via social media. Feasibility of web-based recruitment and data collection among popular diet followers was assessed by survey metrics and response rates. Eight major diet groups were identified, and self-reported weight and height were used to calculate BMI. One-way ANOVA was used to compare BMI across diet groups adjusting for age, sex, US residency, time reported on diet, and medication use. Data were expressed as geometric means and 95% confidence intervals. The ADAPT Pilot Study recruited approximately 2,000 participants from ADAPT FS, over a 6-month period in 2017, to complete 17 online questionnaires (demographics, lifestyle, behavior, and health). Self-reported dietary intake was estimated using online 24-hour recalls. Theoretical dietary intakes were estimated using 21-30 days of meal plans for MyPlate guidelines and two of the most commonly cited diets: WFPB and Paleo. Diet quality was scored using the Healthy Eating Index 2015 (HEI-2015). Degree of adherence was calculated using the Mahalanobis distance equation to compare targeted macronutrient intakes with self-reported intakes. Prevalence of factors that potentially influence dietary adherence was compared across diet followers from low adherence to high adherence.

Results: Aim (1) The large number of enrolled participants (N=13,787) and high survey completion rate (71%) for the Feasibility Survey demonstrated the suitability of web-based research methods to gather data among followers of popular diets. Among participants with complete demographic data (n=9,019), the majority were female (82%) and white (93%). Aim (2) Of Feasibility Survey participants with complete baseline data (n=9,536), the distribution of diets was WFPB (25%); vegan & raw vegan (19%); Paleo (14%); try to eat healthy (TTEH) (11%); vegetarian & pescatarian (9%); whole food (8%); Weston A. Price (5%); and low-carb (4%). Among those who reported following a popular diet for 1-5 yrs (n=4,067), geometric mean BMIs (kg/m2) were lower for all diet groups compared to TTEH (p<0.05). Within diet groups, mean BMI was significantly lower (p<0.05) among longer-term followers (≥1yr) of WFPB, vegan, whole food, and low-carb diets. Aim (3) Ideal derived HEI-2015 scores from meal plans for WFPB and Paleo were 88 and 72 out of 100, respectively. Variation in food groups translated into different nutrient profiles for both diets. Notable differences between WFPB and Paleo were as follows: saturated fat intake (3% for WFBP, 19% for Paleo); dietary fiber requirements were met for older women following a WFBP but not Paleo meal plan; and both meal plans did not meet calcium requirements across all age groups. Mean HEI-2015 scores of a subset of Pilot Study participants using self-reported intake data following TTEH (n=50), WFPB (n=50), and Paleo (n=49), were 57, 73, and 53, respectively. Aim (4) Pilot data generated for the factors associated with the degree of adherence to a diet indicate that more adherent individuals are most likely to be the primary food shopper (86% vs. 72%, WFPB vs. Paleo, respectively), primary food preparer (86% vs. 72%) and take food with them when they leave the house (67% vs. 54%), and least likely to have food inconsistent with their diet in the house (72% vs. 84%).

Conclusions: Web-based research methods were successful in recruiting followers of popular diets, although further strategies are required to recruit more men and to increase racial/ethnic diversity. Estimated BMIs were lowest among individuals who reported making a conscious decision to adhere to a specific dietary pattern for 1-5 yrs compared to those reporting TTEH, as well as those who reported following their diet for >1 year within WFPB, vegan, whole food, and low-carb groups. Theoretical nutrient profiles for WFPB and Paleo diets have higher overall dietary quality compared to typical US intakes, but preliminary data from 24-hr recalls suggests that followers of Paleo diets have lower diet quality while WFPB have higher diet quality. Although factors associated with dietary adherence emerged, the small sample size and limited demographic distribution precludes drawing generalizable conclusions.

Indexing (document details)
Advisor: McKeown, Nicola
Commitee: Economos, Christina, Folta, Sara, Lichtenstein, Alice
School: Tufts University, Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy
Department: Nutritional Epidemiology
School Location: United States -- Massachusetts
Source: DAI-B 79/09(E), Dissertation Abstracts International
Subjects: Nutrition, Epidemiology
Keywords: Adherence, Diet, Diet quality, Paleo, Vegan, Vegetarian
Publication Number: 10822072
ISBN: 978-0-355-94559-1
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