Abstract
To assess intrapair resemblance in changes of body weight, total body fat, fat distribution, resting metabolic rate, fasting respiratory quotient and cardiovascular disease risk factors in response to therapeutic weight loss in female obese identical twins. Patients stayed for 40 days on an inpatient metabolic unit under careful supervision.
The stay was divided into three parts: an initial period of 7 days for adjustment to the hospital environment and for baseline measurements, 28 days of the weight reduction regimen when negative energy balance was achieved mainly by a very low calorie diet (1.6 MJ per day) and 5 days of testing after weight reduction. RESULTS: Subjects lost 8.8 +/- 1.9 kg of weight, from 93.9 +/- 21.2 to 85.1 +/- 10.9 kg (P < 0.0001) and 6.5 +/- 2.3 kg of body fat (P < 0.001).
Weight losses varied widely among subjects, with a high correlation between losses of members of twin pairs for body weight (r = 0.85; P < 0.001) and for body fat (r = 0.88; P < 0.0001). Changes in uric acid resulting from weight loss were also correlated among members of twin pairs whereas changes in blood pressure, cholesterol and triglycerides were not.
CONCLUSION: The great intrapair resemblance observed in very low calorie diet-induced weight and fat losses in female obese identical twins suggests an important role of genetic factors in response to the weight reduction regimen.