Energy, substrate and protein metabolism in morbid obesity before, during and after massive weight loss

• Published in: International Journal of Obesity Vol. 24; no. 6; pp. 711 - 718
• Main Authors: Gemert, W.G. van, Westerterp, K.R, Acker, B.A.C. van, Wagenmakers, A.J.M, Halliday, D, Greve, J.M, Soeters, P.B
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 01.06.2000
• Subjects: Adenosine Triphosphate - metabolism; Adult; bariatric surgery; Basal Metabolism; Body Composition; Body Mass Index; body protein; Deuterium; deuterium oxide; Diet Records; Energy; Energy Metabolism; Exercise; Female; gas exchange; Gastroplasty; Humans; lean body mass; Male; metabolic diseases; Metabolism; Middle Aged; Obesity; Obesity, Morbid - metabolism; Obesity, Morbid - surgery; Oxidation; Oxygen Consumption; patients; physical activity; protein metabolism; Proteins; Proteins - metabolism; Respiration; sleeping metabolic rate; Urine; Weight control; Weight Loss; Netherlands; Germany
• ISSN: 0307-0565; 1476-5497
• DOI: 10.1038/sj.ijo.0801230

OBJECTIVE: To investigate the effect of surgically induced weight loss on energy, substrate and protein metabolism of morbidly obese patients. DESIGN: A prospective, clinical intervention study of morbidly obese patients before and after surgical treatment. SUBJECTS: Eight morbidly obese patients (BMI 47.88 +/- 7.03). METHODS: Total energy expenditure (TEE; doubly labeled water method), sleeping metabolic rate (SMR; respiration chamber), body composition (deuterium oxide component of doubly labeled water), substrate metabolism (48 h dietary records, 48 h urine collection and gaseous exchange in the respiration chamber) and whole body protein turnover (primed-continuous infusion of L-[1-13C]-leucine) were measured before, 3 and 12 months after vertical banded gastroplasty (VBG). RESULTS: The TEE decreased as a result of a decreased SMR (64%) and non-SMR (36%; P = 0.001). SMR as a function of fat-free mass (FFM) decreased after weight loss (P < 0.05). The physical activity index (PAI), defined as TEE/SMR, was low and was not influenced by weight loss. Protein and carbohydrate oxidation decreased significantly after VBG (P < 0.05), although 3 months after VBG protein oxidation did not decrease enough to prevent loss of FFM. The energy used for protein turnover was approximately 24% of SMR and did not change after weight loss. CONCLUSIONS: Compensatory processes that oppose weight loss of morbidly obese patients exist, as demonstrated by the disproportional reduction of SMR, and a low PAI. Protein turnover is not a major contributor to the disproportional reduction of SMR.