Walking economy and exercise efficiency in successful weight loss maintainers.

Purpose: Following short-term weight loss, the energetic cost of transport decreases and exercise efficiency increases. Whether changes persist during long-term weight maintenance is unknown.

Methods: We compared walking economy and exercise efficiency in weight loss maintainers (WLM, maintaining ≥13.6 kg weight loss for ≥1 year), controls without obesity (NC, BMI similar to current BMI of WLM), and controls with overweight/obesity (OC, BMI similar to pre-weight loss BMI of WLM). Energy expenditure (EE) and respiratory quotient were measured using indirect calorimetry at rest, while standing, and during treadmill walking. Gross and net energetic cost of transport (J/kg/m) was measured during level treadmill walking at 0.75, 1.12, and 1.52 m/s. Gross, net, and delta efficiency (%) were measured during inclined treadmill walking (2 %, 4 %, and 6 % grade) and a constant speed (1.12 m/s).

Results: WLM (n = 32, BMI: 23.8 ± 2.3 kg/m²) and NC (n = 28, BMI: 22.7 ± 1.6 kg/m²) had significantly lower EE (kJ/min) compared to OC (n = 26, BMI: 33.0 ± 4.5 kg/m²) during rest, standing, and walking (p < 0.01). Net energetic cost of transport was significantly lower in WLM compared to OC at 1.12 and 1.52 m/s (p < 0.05). Net efficiency was significantly greater in WLM compared to OC while walking (p ≤ 0.05). There were no significant differences between WLM and NC for any measures of economy or efficiency.

Conclusion: WLM had lower walking economy and greater walking efficiency compared to OC, but there were no differences between WLM and NC. Thus, individuals maintaining significant weight loss may be successful with long-term weight loss, in part, due to resistance against adaptive reductions in walking energetics.