Effects of a combined dietary, exercise and behavioral intervention and sympathetic system on body weight maintenance after intended weight loss: Results of a randomized controlled trial

Background: Lifestyle based weight loss interventions are hampered by long-term inefficacy. Prediction of individuals successfully reducing body weight would be highly desirable. Although sympathetic activity is known to contribute to energy homeostasis, its predictive role in body weight maintenance has not yet been addressed.

Objectives: We investigated, whether weight regain could be modified by a weight maintenance intervention and analyzed the predictive role of weight loss-induced changes of the sympathetic system on long-term weight regain.

Design: 156 subjects (age > 18; BMI ≥ 27 kg/m²) participated in a 12-week weight reduction program. After weight loss (T0), 143 subjects (weight loss > 8%) were randomized to a 12-month lifestyle intervention or a control group. After 12 months (T12) no further intervention was performed until month 18 (T18). Weight regain at T18 (regain_BMI) was the primary outcome. Evaluation of systemic and tissue specific estimates of sympathetic system was a pre-defined secondary outcome.

Results: BMI was reduced by 4.67 ± 1.47 kg/m² during the initial weight loss period. BMI maintained low in subjects of the intervention group until T12 (+0.07 ± 2.98 kg/m²; p = 0.58 compared to T0), while control subjects regained +0.98 ± 1.93 kg/m² (p < 0.001 compared to T0). The intervention group regained more weight than controls after ceasing the intervention (1.17 ± 1.34 vs. 0.57 ± 0.93 kg/m²) until T18. Consequently, BMI was not different at T18 (33.49 (32.64; 34.33) vs. 34.18 (33.61; 34.75) kg/m²; p=0.17). Weight loss-induced modification of urinary metanephrine excretion independently predicted regain_BMI (R² = 0.138; p < 0.05). The lifestyle intervention did not modify the course of urinary metanephrines after initial weight loss.

Conclusions: Our lifestyle intervention successfully maintained body weight during the intervention period. However, no long-term effect could be observed beyond the intervention period. Predictive sympathetic activity was not persistently modified by the intervention, which may partially explain the lack of long-term success of such interventions.