Key PointsQuestionWhat are the long-term effects of severe vs moderate energy restriction on lean mass and other aspects of body composition?FindingsThis randomized clinical trial included 101 postmenopausal women with obesity. At 12 months, participants who had undergone severe energy restriction experienced approximately 2-fold greater weight and fat loss, approximately 1.5 times as much loss of whole-body lean mass (proportional to total weight lost), and approximately 2.5 times as much loss of total hip bone mineral density compared with participants who had undergone moderate energy restriction.MeaningAlthough severe energy restriction is an effective obesity treatment, caution is necessary when implementing it in postmenopausal women, especially those with osteopenia or osteoporosis.

We have previously shown that a severely energy-restricted diet leads to greater loss of weight, fat, lean mass and bone mineral density (BMD) at 12 months in postmenopausal women with obesity than a moderately energyrestricted diet. We now aim to evaluate whether these effects are sustained longer term (ie, at 36 months). 101 postmenopausal women were randomized to either 12 months of moderate (25 to 35%) energy restriction with a food-based diet (moderate intervention), or 4 months of severe (65 to 75%) energy restriction with a total meal replacement diet followed by moderate energy restriction for 8 months (severe intervention). Body weight and composition were measured at 0, 24 and 36 months. Participants in the severe intervention lost~1.5 to 1.7 times as much weight, waist circumference, whole-body fat mass and visceral adipose tissue compared to those in the moderate intervention, and were 2.6 times more likely (42% versus 16%) to have lost 10% or more of their initial body weight at 36 months (P < 0.01 for all). However, those in the severe versus moderate intervention lost 1.4 times as much whole-body lean mass (P < 0.01), albeit this was proportional to total weight lost and there was no greater loss of handgrip strength, and they also lost~2 times as much total hip BMD between 0 and 36 months (P < 0.05), with this bone loss occurring in the first 12 months. Thus, severe energy restriction is more effective than moderate energy restriction for reducing weight and adiposity in postmenopausal women in the long term (3 years), but attention to BMD loss in the first year is required. Trial registration: Australian New Zealand Clinical Trials Registry Reference Number: 12612000651886, anzctr.org.au.

With obesity being a leading cause of preventable death, it is vital to understand how best to identify individuals with greater risk of metabolic disease, especially those with high visceral adipose tissue (VAT). This study aimed to determine whether three commonly used waist circumference (WC) measurement sites could provide accurate estimations of VAT, as determined by magnetic resonance imaging (MRI), which is a gold standard for measuring VAT, in postmenopausal women with obesity. VAT volume was measured by MRI of the total abdomen in 97 women aged 57.7 ± 0.4 years (mean ± SEM), mean body mass index 34.5 ± 0.2 kg/m2. WC was measured at the midpoint between the lowest rib and the iliac crest (WCmid), the narrowest point of the torso (WCnarrow), and at the level of the umbilicus (WCumbilicus). WC differed significantly according to measurement site, with WCnarrow (102.1 ± 0.7 cm) < WCmid (108.3 ± 0.7 cm) < WCumbilicus (115.7 ± 0.8 cm) (p < 0.001). WCmid, WCnarrow and WCumbilicus were all significantly correlated with VAT, as measured by MRI (r = 0.581, 0.563 and 0.390, respectively; p < 0.001 for all), but the relationships between WCmid or WCnarrow and VAT determined by MRI were stronger than for WCumbilicus. Measurement of either WCmid or WCnarrow provides valid estimates of VAT in postmenopausal women with obesity, with WCnarrow being favoured in light of its greater ease and speed of measurement in this population.

Background: Previous research showed that weight-reducing diets increase appetite sensations and/or circulating ghrelin concentrations for up to 36 months, with transient or enduring perturbations in circulating concentrations of the satiety hormone peptide YY.Objective: This study assessed whether a diet that is higher in protein and low in glycemic index (GI) may attenuate these changes.Methods: 136 adults with pre-diabetes and a body mass index of ≥25 kg/m2 underwent a 2-month weight-reducing total meal replacement diet. Participants who lost ≥8% body weight were randomized to one of two 34-month weight-maintenance diets: a higher-protein and moderate-carbohydrate (CHO) diet with low GI, or a moderate-protein and higher-CHO diet with moderate GI. Both arms involved recommendations to increase physical activity. Fasting plasma concentrations of total ghrelin and total peptide YY, and appetite sensations, were measured at 0 months (pre-weight loss), at 2 months (immediately post-weight loss), and at 6, 12, 24, and 36 months.Results: There was a decrease in plasma peptide YY concentrations and an increase in ghrelin after the 2-month weight-reducing diet, and these values approached pre-weight-loss values by 6 and 24 months, respectively (P = 0.32 and P = 0.08, respectively, vs. 0 months). However, there were no differences between the two weight-maintenance diets. Subjective appetite sensations were not affected by the weight-reducing diet nor the weight-maintenance diets. While participants regained an average of ~50% of the weight they had lost by 36 months, the changes in ghrelin and peptide YY during the weight-reducing phase did not correlate with weight regain.Conclusion: A higher-protein, low-GI diet for weight maintenance does not attenuate changes in ghrelin or peptide YY compared with a moderate-protein, moderate-GI diet.Clinical Trial Registry:ClinicalTrials.gov registry ID NCT01777893 (PREVIEW) and ID NCT02030249 (Sub-study).