Adaptive Thermogenesis After Hypocaloric Low‐Carbohydrate Versus Low‐Fat Diets in African American Women: A Secondary Analysis

This secondary analysis was conducted to compare the magnitude of adaptive thermogenesis (AT) following hypocaloric low-carbohydrate (CHO) versus low-fat diets in African American (AA) women. Sixty-nine AA women with obesity were randomized to low-CHO or low-fat hypocaloric diets for 10 weeks, followed by a 4-week weight stabilization period (all food provided). At baseline and Week 13, insulin sensitivity (SI) was measured by intravenous glucose tolerance test, body composition by bioimpedance analysis, total energy expenditure (EE) (TEE) by doubly labeled water, and resting EE (REE) by indirect calorimetry. Forty women finished the intervention, with an average weight loss of 6.3 ± 3.9 kg and no differences between groups. AT was present at the level of REE (-75 ± 136 kcal/day, p < 0.003, n = 38), but not TEE (-80 ± 288 kcal/day, p = 0.086, n = 40) at Week 13. Women with low SI on the low-fat diet showed greater AT at the level of TEE compared to those on the low-CHO diet (-202 ± 213 vs. 127 ± 239 kcal/day, respectively, p < 0.006). AA women with low SI on low-CHO diets do not experience AT, which can contribute to the superiority of this dietary approach in inducing weight and fat mass loss. ClinicalTrials.gov Identifier: NCT03499509 https://clinicaltrials.gov/study/NCT03499509.