For postmenopausal women with obesity, a severely energy-restricted diet resulted in a 2-fold greater decrease in weight compared with a moderately restricted diet in a 12-month randomized study, but was also associated with a much higher risk for loss of bone mineral density (BMD), according to study results published in JAMA Network Open.
Researchers used data from the Type of Energy Manipulation for Promoting Optimum Metabolic Health and Body Composition in Obesity (TEMPO) Diet Trial to assess differences in lean mass and other measures of body composition after severe vs moderate energy restriction. Postmenopausal women with obesity (body mass index 30-40 kg/m2) ranging from 45 to 65 years of age were randomly assigned to a 12-month moderately restricted food-based diet group (25%-35% restriction relative to estimated energy expenditure; n=51) or a severe energy-restriction group (65%-75% restriction relative to estimated energy expenditure; n=50) consisting of 4 months of a meal replacement diet followed by 8 months of the moderately restricted diet. The severely restricted diet used meal replacement shakes and soups and was supplemented with whey protein isolate. Physical activity was encouraged but not supervised and participants were not eligible if they had more than 3 hours of structured exercise a week.
More than 80% of women in the severe-restriction group lost at least 10% of their baseline weight compared with less than 30% of women in the moderate-restriction group (P <.001). While the severely restricted diet did not result in significant decrease in muscle (handgrip) strength or a disproportionate loss of whole-body lean mass, it did result in a significant decrease in total hip BMD compared with the moderate diet (effect size, -0.017 g/cm2; 95% CI, -0.029 to -0.005 g/cm2; P =.002).
While women in both the severe and moderate groups experienced decreased BMD at the total hip, there was a significant increase in the incidence of osteopenia in the femoral neck region in the severe group, from 16% at baseline to just over 39% by the end of the 12-month period. There was no significant difference between the 2 groups in the incidence of osteopenia in the hip region as a whole.
Overall, this trial showed that severely restricting calorie intake through meal replacements can greatly increase short- and long-term weight loss in postmenopausal women with obesity, but these positive results were associated with a significant decrease in hip BMD. Although these results do not indicate that postmenopausal women should not partake in this weight-loss method, clinicians should consider baseline BMD before deciding to implement severe energy restriction.
Disclosure: Prima Health Solutions provided meal replacements at decreased prices and provided meal-replacement accessories (shakers) free of charge. This relationship was established after the dietary protocol for the TEMPO Diet Trial had been established.
Seimon RV, Wild-Taylor AL, Keating S, et al. Effect of weight loss via severe vs moderate energy restriction on lean mass and body composition among postmenopausal women with obesity: the TEMPO diet randomized clinical trial. JAMA Netw Open. 2019;2(10):e1913733.