# Obesity risk in African American women is determined by a diet-by-phenotype interaction

> **NIH NIH R01** · UNIVERSITY OF ALABAMA AT BIRMINGHAM · 2020 · $648,373

## Abstract

Summary
 African-American (AA) women are disproportionately burdened by obesity. Our published data have
led to the provocative hypothesis that this disparity has physiologic underpinnings. Specifically, AA women are
characterized by a high acute insulin secretory response to a glucose challenge, as well as reduced hepatic
insulin extraction, which together lead to postprandial circulating insulin concentrations that can be several fold
higher than those observed in Caucasian (European-American, EA) women. The lipogenic actions of insulin
could favor partitioning of energy to adipose tissue at the expense of ATP (energy) production. In fact, AA
women have lower energy requirements than EA women, and are more energetically efficient. High insulin
secretion, however, is only one factor that determines insulin action; another major factor is insulin sensitivity.
Our data have shown that over time, weight (fat) gain in obesity-prone AA women is higher in those who are
more insulin sensitive, whereas “obesity-resistant” (constitutionally lean) AA women have relatively lower
insulin sensitivity. Our data also suggest that the lipogenic actions of insulin in AA women are exacerbated by
a high-glycemic diet, which promotes insulin secretion. Finally, our data have shown that over time weight (fat)
gain in AA women is predicted by the combination of insulin sensitivity and dietary glycemic load. Taken
together, these observations suggest that many AA women are predisposed to obesity by their
endocrine make-up, and that this predisposition is exacerbated by a high-glycemic diet. A natural
corollary of this hypothesis is that for implementation of intentional weight loss, a low- (vs high-) glycemic diet
will promote greater loss of body fat, and will enable successful weight loss maintenance by increasing energy
expenditure. This corollary is supported by our preliminary data that indicate a 50% greater loss of fat with
low- vs high-glycemic diet under controlled conditions in AA women. The project proposed herein will test
these hypotheses through a randomized clinical weight loss trial of high- vs low-glycemic diets in obese AA
women. The study has both an efficacy phase (controlled feeding during weight loss) to probe physiologic
mechanisms (energy expenditure, metabolic efficiency), and an effectiveness phase (6-month free-living
follow-up) to test the hypothesis that the low-glycemic diet will be more effective at promoting weight loss
maintenance due in part to improved adherence and quality of life, and ease of implementing the diet. This
study is innovative in that it proposes to test a specific physiologic mechanism that may underlie propensity to
obesity; it includes both efficacy and effectiveness outcomes; it involves both quantitative and qualitative
methodology; and it tackles optimization of both weight loss and weight loss maintenance. This study is
intended to provide the evidence base necessary to improve the clinical care approach to weig...

## Key facts

- **NIH application ID:** 9914264
- **Project number:** 5R01DK115483-03
- **Recipient organization:** UNIVERSITY OF ALABAMA AT BIRMINGHAM
- **Principal Investigator:** BARBARA A GOWER
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $648,373
- **Award type:** 5
- **Project period:** 2018-09-01 → 2023-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9914264

## Citation

> US National Institutes of Health, RePORTER application 9914264, Obesity risk in African American women is determined by a diet-by-phenotype interaction (5R01DK115483-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9914264. Licensed CC0.

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