Energy, substrate and protein metabolism in morbid obesity before, during and after massive weight loss.
OBJECTIVE
To investigate the effect of surgically induced weight loss on energy, substrate and protein metabolism of morbidly obese patients.


METHODS
A prospective, clinical intervention study of morbidly obese patients before and after surgical treatment.


METHODS
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.
van Gemert
W G
WG
Departments of Surgery and Human Biology, University Hospital Maastricht, PO box 5800, 6202 AZ, Maastricht, The Netherlands. wg.gemert@wxs.nl
Westerterp
K R
KR
van Acker
B A
BA
Wagenmakers
A J
AJ
Halliday
D
D
Greve
J M
JM
Soeters
P B
PB
D000255:Adenosine Triphosphate / Q000378:metabolism; D000328:Adult; D001481:Basal Metabolism; D001823:Body Composition; D015992:Body Mass Index; D015930:Diet Records; D004734:Energy Metabolism; D005260:Female; D015391:Gastroplasty; D006801:Humans; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000378:metabolism* / Q000601:surgery*; D010101:Oxygen Consumption; D011506:Proteins / Q000378:metabolism*; D015431:Weight Loss
D011506:Proteins; D000255:Adenosine Triphosphate