Doctoral Candidate
Karlsen, Micaela.
2018
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Abstract:
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 ... read morean 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.
Thesis (Ph.D.)--Tufts University, 2018.
Submitted to the Dept. of Nutritional Epidemiology.
Advisor: Nicola McKeown.
Committee: Alice Lichtenstein, Sara Folta, and Christina Economos.
Keywords: Nutrition, and Epidemiology.read less - ID:
- p5548318j
- Component ID:
- tufts:25037
- To Cite:
- TARC Citation Guide EndNote
