Reductions in body weight and insulin resistance are not associated with changes in grey matter volume or cortical thickness during the PREVIEW study.

INTRODUCTION: The effect of changes in body weight or insulin resistance on grey matter volume and cortical thickness change are unclear. The present observational study assessed effects of an 8-week weight loss period (≥8% of body weight), and a subsequent 22-month weight maintenance period on grey matter volume and cortical thickness. METHODS: A total of 24 participants (12f/12 m; age 52.8 ±â€¯10.6 years) with overweight/obesity and pre-diabetes were recruited. T1-weighted magnetic resonance imaging was used to determine grey matter volume and cortical thickness at baseline, after the weight loss period and after a medium to high dietary protein weight maintenance period. RESULTS: At baseline, global grey matter volume was inversely associated with HOMA-IR, adjusted for sex and age (r = -0.42; p = .049). During the weight loss period participants decreased their BMI (32.1 ±â€¯3.3 to 28.1 ±â€¯2.8 kg/m2, p < .01), body-fat (41.6 ±â€¯6.4 to 35.0 ±â€¯8.0%, p < .01) and insulin resistance (HOMA-IR: 4.0 ±â€¯2.0 to 1.8 ±â€¯0.9, p < .01). During the 22-month weight maintenance period, these parameters gradually increased again (BMI: 29.3 ±â€¯3.8 kg/m2; body-fat: 37.8 ±â€¯9.3%; HOMA-IR: 2.9 ±â€¯1.4, p < .01). Global grey matter volume and cortical thickness did not change significantly during the weight loss or weight maintenance period. Changes in body weight, body-fat percentage or insulin sensitivity were not associated with changes in global grey matter volume. CONCLUSION: In conclusion, we confirmed that global grey brain matter volume was inversely associated with insulin resistance at baseline, yet an intervention yielding a decrease in insulin resistance did not lead to changes in global grey brain matter volume or cortical thickness. TRIAL REGISTRATION: The trial is registered with ClinicalTrials.gov, NCT01777893.

Long-term effects of increased protein intake after weight loss on intrahepatic lipid content and implications for insulin sensitivity: a PREVIEW study.

The aim of this study was to assess the effects of a weight maintenance period comprising two diets differing in protein intake, after weight loss, on intrahepatic lipid content and implications for insulin sensitivity. A total of 25 participants [body mass index (BMI): 31.1 (3.5 kg/m2; intrahepatic lipid (IHL): 8.7 (8.3%; fasting glucose: 6.4 (0.6 mmol/l; homeostatic model assessment for insulin resistance (HOMA-IR): 3.7 (1.6; Matsuda index: 3.4 (2.9] started an 8-wk low-energy diet followed by a 2-yr weight maintenance period with either high protein or medium protein dietary guidelines. At baseline, after 6 mo, and after 2 yr, IHL, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) were determined by magnetic resonance spectroscopy/imaging. Glucose and insulin concentrations, determined during an oral glucose challenge, were used to assess the HOMA-IR and Matsuda insulin sensitivity index (ISI). Protein intake was measured with 24-h urinary nitrogen excretion. Protein intake, BMI, IHL, VAT, SAT, HOMA-IR, and ISI did not change differently between the groups during the intervention. In the whole group, BMI, IHL, VAT, SAT, HOMA-IR, and ISI were favorably changed at 6 mo and 2 yr compared with baseline ( P < 0.05). Mixed-model analysis showed that independent of BMI, protein intake (g/d) at 6 mo was inversely related to IHL (coefficient: -0.04; P < 0.05) and VAT (coefficient: -0.01; P < 0.05). Overall, IHL was positively related to HOMA-IR (coefficient: 0.10; P < 0.01) and inversely related to ISI (coefficient: -0.17; P < 0.01), independent of BMI. A 2-yr medium- to high-protein energy-restricted diet reduced IHL and VAT. Independently of changes in BMI, IHL was inversely related to insulin sensitivity.

Sleep efficiency as a determinant of insulin sensitivity in overweight and obese adolescents.

UNLABELLED: Insulin resistance (IR) occurs in a transient manner during puberty. Obese adolescents may be at risk for persistent IR during puberty. The objective of the study is to review the literature on the association of the anthropometry and lifestyle characteristics with insulin sensitivity in overweight and obese adolescents, and include data from a new study. Relevant papers were selected and reviewed. In addition, 137 overweight and obese adolescents (42 male/95 female, age 14.4 ± 2.3 years, BMI z-score +3.3 ± 0.7, HOMA-IR 3.4 ± 1.8) from the Centre for Overweight Adolescent and Children's Healthcare (MUMC+) were included in this study. Anthropometrics, Tanner stages, sleep characteristics, food intake behaviour and physical activity were determined, and possible associations with homeostasis model assessment of insulin resistance (HOMA-IR) were tested. RESULTS: Overweight and obese adolescents with unfavourable fat partitioning and family history of NIDDM are at risk for persistent IR. Overweight and obese adolescents from the new cohort showed a higher HOMA-IR postpubertally. BMI z-score, age, pubertal stage and prepubertally total sleeping time (TST) and sleep efficiency (SE) were identified as significant contributors. Overweight and obese adolescents showed a persistently higher instead of transiently higher HOMA-IR during puberty, associated with BMI z-score, age, pubertal stage and prepubertally less TST and SE.

Children With Morbid Obesity Benefit Equally as Children With Overweight and Obesity From an Ongoing Care Program.

CONTEXT: Despite stabilization of childhood overweight and obesity prevalence, there is a shift toward more severe degrees of obesity, which results in an increasing prevalence of children with morbid obesity. Prior studies demonstrated that lifestyle modification without ongoing treatment has only a modest and not sustainable effect in children with morbid obesity. This suggests that a chronic care model is necessary for long-term effects on weight management and health. OBJECTIVE: This study aimed to evaluate the effect of an ongoing lifestyle intervention in children with morbid obesity in comparison with children with overweight and obesity. DESIGN AND SETTING: This was a nonrandomized prospective intervention study with 12- and 24-month followup at the Centre for Overweight Adolescent and Children's Healthcare. PATIENTS AND INTERVENTION: Children and adolescents (n = 100 females and 72 males) with overweight, obesity, or morbid obesity were given long-term, outpatient, tailored lifestyle intervention. MAIN OUTCOME MEASURE: Body mass index (BMI) z score was measured. RESULTS: In children with morbid obesity, 12- and 24-month interventions resulted in a decrease of BMI z score of -0.13 ± 0.25 (P = .001) and -0.23 ± 0.32 (P = .01) respectively, whereas weight status category improved to obese in 21% and 25% of the children. Cardiovascular risk parameters including serum total cholesterol, low-density lipoprotein cholesterol, glycosylated hemoglobin (HbA1c), and diastolic blood pressure significantly improved after 1-year intervention in the complete group. Most important, BMI z score as well as cardiovascular risk parameters improved to a similar degree in children with overweight, obesity, and morbid obesity. CONCLUSIONS: Children with overweight, obesity, and morbid obesity benefit equally from an ongoing, outpatient, tailored lifestyle intervention, and demonstrate significant weight loss and improvement of cardiovascular risk parameters.