Changes in Resting Energy Expenditure in Response to Different Dietary Patterns: A Randomized Clinical Trial...

Area of Science:

• Metabolism and Nutrition
• Obesity Research
• Dietary Interventions

Background:

• Limited evidence compares novel diets like ketogenic diets (KD), time-restricted eating (TRE), and modified alternate-day fasting (mADF) against a standard Mediterranean diet (MedDiet) for resting energy expenditure (REE).
• Understanding REE changes is crucial for managing obesity and weight maintenance.

Purpose of the Study:

• To compare the effects of calorie-restricted KD, TRE, and mADF on REE in adults with obesity against a standard MedDiet.
• To identify which dietary strategies, if any, influence REE trajectories differently.

Main Methods:

• A secondary analysis of a 3-month randomized clinical trial involving 160 adults with obesity (BMI > 30 kg/m²).
• Participants followed one of five calorie-restricted diets (MedDiet, KD, eTRE, lTRE, mADF) with a 600 kcal/day deficit.
• Resting energy expenditure (REE) was measured via indirect calorimetry, and trajectories were analyzed using Linear Mixed Models (LMMs) in 102 participants.

Main Results:

• No statistically significant differences in adjusted REE trajectories were observed among the five dietary groups over the 3-month intervention.
• Total body weight and biological sex were the strongest predictors of REE, independent of the dietary intervention.
• Circulating beta-hydroxybutyrate levels did not show independent associations with REE trajectories.

Conclusions:

• Hypocaloric diets with varied macronutrient profiles and fasting schedules did not significantly alter REE trajectories in individuals with obesity over 3 months.
• Individual biological factors like body weight and sex appear to be more influential on REE than the specific dietary approach.
• These exploratory findings require confirmation in larger, prospective trials due to the study's modest sample size.