Abstract
The menopause is accompanied by increased risk of obesity, altered body fat distribution, and decreased skeletal muscle mass. The resulting decrease in RMR should be accompanied by a compensatory change in energy balance to avoid weight gain. We aimed to investigate habitual energy intake and expenditure in pre- and post-menopausal women matched for abdominal obesity. We recruited fifty-one healthy Caucasian women, BMI >18.5 and < 35, aged 35 - 45 years (pre-menopausal, n=26) and 55-65 years (post-menopausal, n=25). Energy intake was measured using 3-day diet diaries and dietary fat quality assessed using adipose tissue fatty acid biomarkers. RMR was measured using indirect calorimetry, and total (TEE) and activity energy expenditure using a combined accelerometer and heart rate monitor. Post-menopausal women had lower RMR and TEE and spent significantly less time undertaking moderate exercise than pre-menopausal women. Post-menopausal women had a tendency for a lower calorie intake, and a similar macronutrient intake but a significantly lower adipose tissue n-6/n-3 index (24.6 (1.6) v 37.7 (3.1), P<0.001). The main lifestyle determinant of bone mineral density, (which was significantly lower in post-menopausal women), was TEE for pre-menopausal women, and dietary n-6/n-3 index for post-menopausal women. Our results suggest that weight maintenance is achieved in the post- compared with pre-menopausal status through a combination of reduced energy intake and reduced TEE in a regime that compromises micronutrient intake and negatively impacts on lean tissue mass. However, lower n-6/n-3 fatty acid intake in post-menopausal women is associated with greater bone mineral density.