Background: Insulin resistance and accumulation of visceral adipose tissue (VAT) and intermuscular adipose tissue (IMAT) place aging adults with obesity at high risk of cardio-metabolic disease. A very low carbohydrate diet (VLCD) may be a means of promoting fat loss from the visceral cavity and skeletal muscle, without compromising lean mass, and improve insulin sensitivity in aging adults with obesity. Objective: To determine if a VLCD promotes a greater loss of fat (total, visceral and intermuscular), preserves lean mass, and improves insulin sensitivity compared to a standard CHO-based/low-fat diet (LFD) in older adults with obesity. Design: Thirty-four men and women aged 60–75 years with obesity (body mass index [BMI] 30-40 kg/m²) were randomized to a diet prescription of either a VLCD (< 10:25:> 65% energy from CHO:protein:fat) or LFD diet (55:25:20) for 8 weeks. Body composition by dual-energy X-ray absorptiometry (DXA), fat distribution by magnetic resonance imaging (MRI), insulin sensitivity by euglycemic hyperinsulinemic clamp, and lipids by a fasting blood draw were assessed at baseline and after the intervention. Results: Participants lost an average of 9.7 and 2.0% in total fat following the VLCD and LFD, respectively (p < 0.01). The VLCD group experienced ~ 3-fold greater loss in VAT compared to the LFD group (− 22.8% vs − 1.0%, p < 0.001) and a greater decrease in thigh-IMAT (− 24.4% vs − 1.0%, p < 0.01). The VLCD group also had significantly greater thigh skeletal muscle (SM) at 8 weeks following adjustment for change in total fat mass. Finally, the VLCD had greater increases in insulin sensitivity and HDL-C and decreases in fasting insulin and triglycerides compared to the LFD group. Conclusions: Weight loss resulting from consumption of a diet lower in CHO and higher in fat may be beneficial for older adults with obesity by depleting adipose tissue depots most strongly implicated in poor metabolic and functional outcomes and by improving insulin sensitivity and the lipid profile. Trial registration: NCT02760641. Registered 03 May 2016 - Retrospectively registered.

Objective Qualitative aspects of diet may affect body composition and propensity for weight gain or loss. We tested the hypothesis that consumption of a relatively low glycemic load (GL) diet would reduce total and visceral adipose tissue under both eucaloric and hypocaloric conditions. Design and Methods Participants were 69 healthy overweight men and women. Body composition was assessed by DXA and fat distribution by CT scan at baseline, after 8 weeks of a eucaloric diet intervention, and after 8 weeks of a hypocaloric (1000 kcal/day deficit) diet intervention. Participants were provided all food for both phases, and randomized to either a low GL diet (75 points per 1000 kcal, n = 29). Results After the eucaloric phase, participants who consumed the low GL diet had 11% less intra‐abdominal fat (IAAT) than those who consumed the high GL diet (P < 0.05, adjusted for total fat mass and baseline IAAT). Participants lost an average of 5.8 kg during the hypocaloric phase, with no differences in the amount of weight loss with diet assignment (P = 0.39). Following weight loss, participants who consumed the low GL diet had 4.4% less total fat mass than those who consumed the high GL diet (P < 0.05, adjusted for lean mass and baseline fat mass). Conclusions Consumption of a relatively low GL diet may affect energy partitioning, both inducing reduction in IAAT independent of weight change, and enhancing loss of fat relative to lean mass during weight loss.

Objective Evidence suggests intermuscular adipose tissue (IMAT) may be linked to insulin resistance, whereas thigh subcutaneous adipose tissue (SAT) may be related favorably with indices of metabolic health. However, whether adipose tissue depots of the thigh are differentially related to insulin sensitivity independent of total adiposity and other adipose tissue depots has not been determined. The objective of this study was to identify independent associations of the subcompartments of adipose tissue of the thigh with insulin sensitivity among 97 healthy early postmenopausal women. Materials and Methods Computed tomography (CT) scans of the mid-thigh were used to assess Thigh-SAT, Thigh perimuscular adipose tissue (PMAT), and Thigh-IMAT. CT scans at the L4-L5 intervertebral space were used to assess intra-abdominal adipose tissue (IAAT) and Abdominal-SAT. Total body fat was measured by dual-energy X-ray absorptiometry (DXA). The insulin sensitivity index (S _I) was assessed by using a frequently sampled intravenous glucose tolerance test with minimal model analysis. Results Results indicated S _I was positively associated with Thigh-SAT independent of total fat mass and other adipose tissue compartments. Among all women combined, S _I was inversely associated with Thigh-IMAT independent of total fat mass. However, the relationship between S _I and Thigh-IMAT was independent of IAAT only among women with high levels of Thigh-IMAT and IAAT. Conclusions This is the first study to demonstrate independent, opposing relationships of Thigh-SAT and Thigh-IMAT with insulin sensitivity in healthy postmenopausal women. Further research is needed to determine if these associations are causal in nature.

Among postmenopausal women, declining estrogen may facilitate fat partitioning from the periphery to the intra‐abdominal space. Furthermore, it has been suggested that excess androgens contribute to ...