Diet and exercise training effects on resting metabolic rate

Area of Science:

• Exercise Physiology
• Metabolic Health
• Weight Management

Background:

• Caloric restriction for weight loss often leads to a decrease in resting metabolic rate (RMR).
• This metabolic adaptation can hinder long-term weight management.
• The role of exercise in mitigating RMR decline during caloric restriction requires further investigation.

Purpose of the Study:

• To determine if daily aerobic activity or intermittent prescribed exercise can prevent RMR decline during caloric restriction.
• To assess the impact of different exercise regimens on cardiorespiratory fitness (VO2 max) alongside weight loss.

Main Methods:

• Seventy-eight overweight/obese adults were randomized into three groups: control (no exercise), daily aerobic activity (Group D), or prescribed exercise every other day (Group P).
• All groups followed a 12-week caloric restriction diet (1200-1800 kcal/day).
• Resting metabolic rate (RMR) and maximal oxygen consumption (VO2 max) were measured.

Main Results:

• Both daily (Group D) and intermittent (Group P) exercise significantly increased VO2 max compared to the control group.
• Intermittent prescribed exercise (Group P) resulted in a significantly greater increase in RMR compared to control and daily activity groups.
• A significant positive correlation was observed between changes in VO2 max and RMR across all subjects, stronger in females.

Conclusions:

• Prescribed exercise training performed every other day is effective in preventing the decline in RMR during caloric restriction.
• This exercise regimen also enhances cardiorespiratory fitness.
• Exercise timing and prescription may play a crucial role in metabolic adaptation during weight loss interventions.