Subsequent Weight Maintenance Research Articles

Digital Health Solutions for Weight Loss and Obesity: A Narrative Review.

Personal exercise programmes have long been used and prescribed for weight loss and the improvement of quality of life in obese patients. While individualised programmes are usually the preferred option, they can be more costly and challenging to deliver in person. A move to digital programmes with a wider reach has commenced, and demand has increased due to the SARS-CoV-2 pandemic. In this review, we evaluate the current status of digital exercise programme delivery and its evolution over the past decade, with a focus on personalisation. We used specific keywords to search for articles that met our predetermined inclusion and exclusion criteria in order to provide valuable evidence and insights for future research. We identified 55 studies in total in four key areas of focus, from the more recent development of apps and personal digital assistants to web-based programmes and text or phone call interventions. In summary, we observed that apps may be useful for a low-intensity approach and can improve adherence to programmes through self-monitoring, but they are not always developed in an evidence-based manner. Engagement and adherence are important determinants of weight loss and subsequent weight maintenance. Generally, professional support is required to achieve weight loss goals.

Changes in body composition and homeostatic control of resting energy expenditure during dietary weight loss.

Adaptive thermogenesis (AT) is the mass-independent decrease in energy expenditure (EE) in response to caloric restriction and weight loss. AT becomes manifest throughout all periods of weight loss and persists during subsequent weight maintenance. AT occurs in resting and nonresting energy expenditure as ATREE and ATNREE , respectively. ATREE appears in different phases of weight loss, each with likely different mechanisms. By contrast, during weight maintenance after weight loss, ATNREE exceeds ATREE . Some of the mechanisms of AT are known now and others are not. Future studies on AT will need an appropriate conceptual framework within which to design experiments and interpret results.

Literature Review On Factors Influencing Milk Consumption Behaviour Among Adults

Introduction:Milk and dairy products are good sources of high-quality protein. Protein is important during weight loss and subsequent weight maintenance due to the high satiating effect which helps to prevent over-consumption of energy and thereby reduces body fat stores. Furthermore, dairy protein is a good source of essential amino acids for muscle protein synthesis and thus helps to maintain metabolically active muscle mass during weight loss. Regarding milk consumption, it is important to find the association between personal, environmental, and behaviour factors with consuming milk. Objective: The aim of the study is to identify factors influencing milk consumption behaviour among adults. Methods: This study is based on the literature review and on different case studies from different parts of the world to try to fulfill the main scope of factors influencing milk consumption. Results: Based on this review, environmental factors were found to be the main influences on milk consumption behaviour, followed by personal factors and behaviour factors. Conclusion : This review is also expected to enrich the documentation on the influencing of milk consumption behaviour among adults

Perceived stress as a predictor of eating behavior during the 3-year PREVIEW lifestyle intervention

BackgroundTo better support participants to achieve long-lasting results within interventions aiming for weight loss and maintenance, more information is needed about the maintenance of behavioral changes. Therefore, we examined whether perceived stress predicts the maintenance of changes in eating behavior (flexible and rigid restraint of eating, disinhibition, and hunger).MethodsThe present study was a secondary analysis of the PREVIEW intervention including participants with overweight (BMI ≥ 25 kg/m2) at baseline and high risk of type 2 diabetes (n = 1311). Intervention included a 2-month low-energy diet phase and a 34-month subsequent weight maintenance phase. The first 6 months were considered an active behavior change stage and the remaining 2.5 years were considered a behavior maintenance stage. Eating behavior was measured using the Three Factor Eating Questionnaire and stress using the Perceived Stress Scale. The associations between stress and eating behavior were analyzed using linear mixed effects models for repeated measurements.ResultsPerceived stress measured after the active behavior change stage (at 6 months) did not predict changes in eating behavior during the behavior maintenance stage. However, frequent high stress during this period was associated with greater lapse of improved flexible restraint (p = 0.026). The mean (SD) change in flexible restraint from 6 to 36 months was −1.1 (2.1) in participants with frequent stress and −0.7 (1.8) in participants without frequent stress (Cohen’s ds (95% CI) = 0.24 (0.04–0.43)). Higher perceived stress at 6 months was associated with less flexible restraint and more disinhibition and hunger throughout the behavior maintenance stage (all p < 0.001).ConclusionsPerceived stress was associated with features of eating behavior that may impair successful weight loss maintenance. Future interventions should investigate, whether incorporating stress reduction techniques results in more effective treatment, particularly for participants experiencing a high stress level.

Effects of low-calorie and different weight-maintenance diets on IgG glycome composition.

Obesity-induced inflammation activates the adaptive immune system by altering immunoglobulin G (IgG) glycosylation in a way to produce more proinflammatory antibodies. The IgG glycome has already been well studied, and its alterations are correlated with a high body mass index (BMI) and central adiposity. Still, the IgG N-glycome susceptibility to different dietary regimes for weight control after the initial weight loss has not been studied. To explore changes in IgG glycosylation induced by weight loss and subsequent weight-maintenance diets, we analyzed 1,850 IgG glycomes from subjects in a dietary intervention Diogenes study. In this study, participants followed a low-calorie diet (LCD) providing 800 kcal/d for 8 weeks, followed by one of five weight-maintenance diets over a 6-month period. The most significant alteration of the IgG N-glycome was present 8 weeks after the subjects underwent an LCD, a statistically significant decrease of agalactosylated and the increase of sialylated N glycans. In the follow-up period, the increase in glycans with bisecting GlcNAc and the decrease in sialylated glycans were observed. Those changes were present regardless of the diet type, and we did not observe significant changes between different diets. However, it should be noted that in all five diet groups, there were individuals who prominently altered their IgG glycome composition in either proinflammatory or anti-inflammatory directions.

Weight loss-induced improvement of body weight and insulin sensitivity is not amplified by a subsequent 12-month weight maintenance intervention but is predicted by adaption of adipose atrial natriuretic peptide system: 48-month results of a randomized controlled trial

BackgroundBehavioral weight loss interventions are frequently hampered by long-term inefficacy. As metabolic improvements and health-related quality of life (HRQoL) are diminished by weight regain, effective long-term strategies are highly desirable. We aimed to analyze whether an additional weight maintenance intervention could delay body weight regain and can induce a long-term improvement of metabolism and HRQoL for up to 48 months in humans. Given the short-term metabolic effects of natriuretic peptides (NP), we also investigated the role of the adipose atrial NP (ANP) system in this long-term context.MethodsAfter a successful 12-week weight reduction program 143 subjects (age>18; BMI≥27 kg/m2) were randomized (1:1) to a control group or a 12-month multimodal weight maintenance intervention focusing on nutritional counseling and physical exercises. Secondary trial outcomes including course of BMI, HOMA-IR, glucose response after oGTT (glucoseAUC), and HRQoL (SF-36) were analyzed yearly for 48 months. Adipose ANP receptor mRNA expression was analyzed during weight loss.ResultsInitial weight loss (− 4.7±1.5 kg/m2) improved glucoseAUC, HOMA-IR, and HRQoL. Although BMI was still reduced after 48 months (−1.98 [95% CI −2.61, −1.35] kg/m2), benefits on HOMA-IR, glucoseAUC, and mental health disappeared after 36 (−0.49 [−1.00, 0.02]), 18 (0.61 [−9.57, 10.79] mg dl−1 min−1), and 18 months (2.06 [−0.08, 4.20]), respectively, while improved physical health persisted up to months 48 (2.95 [0.49, 5.40]). Weight maintenance intervention inhibited weight regain and delayed impairment of HOMA-IR and glucoseAUC (but not HRQoL) for up to 12 months. However, no metabolic long-term effect was seen beyond the intervention period. Lower adipose NPR-C and higher NPR-A mRNA expression after weight loss predicted smaller regain of weight (r=0.398; p<0.05)/fat mass (FM) (r=0.391; p<0.05) and longer improvement of HOMA-IR (r=−0.422; p<0.05), respectively.ConclusionsAdditional benefits of a behavioral 12-month weight maintenance intervention after weight loss regarding body weight regain and metabolic improvement does not persist beyond the intervention period. However, weight loss-induced modulation of the adipose ANP system is probably involved in the long-term control of body weight regain and insulin sensitivity.Trial registrationClinicalTrials.govNCT00850629. Registered on February 25, 2009.

Physical Activity, Weight Loss, and Weight Maintenance in the DiOGenes Multicenter Trial.

In this secondary analysis of the DiOGenes study, we investigated whether physical activity (PA) contributes to diet-induced weight loss and helps to reduce subsequent regain. We also studied the associations of PA with changes in cardiometabolic variables. Adults with overweight were included and followed an 8-week low-calorie diet (LCD). When successful (>8% weight loss), participants were randomized to different ad libitum diet groups and were advised to maintain their weight loss over the 6-month intervention period. Body weight (BW), body composition, cardiometabolic variables and subjectively-assessed PA were measured at baseline, at the end of weight loss and at the end of the intervention. BW was reduced by the LCD (from 99.8 ± 16.7 to 88.4 ± 14.9 kg; P < 0.001). This reduction was maintained during the weight maintenance period (89.2 ± 16.0 kg). Total PA (sum score of the three subscales of the Baecke questionnaire) increased during the weight loss period (from 8.16 ± 0.83 to 8.39 ± 0.78; P < 0.001) and this increase was subsequently maintained (8.42 ± 0.90). We found no evidence that baseline PA predicted weight loss. However, a higher level of baseline PA predicted a larger weight-loss-induced improvement in total cholesterol, triglycerides, glucose and CRP, and in post-prandial insulin sensitivity (Matsuda index). Subsequent weight and fat mass maintenance were predicted by the post-weight loss level of PA and associated with changes in PA during the weight maintenance phase. In conclusion, despite the fact that higher baseline levels of PA did not predict more weight loss during the LCD, nor that an increase in PA during the LCD was associated with more weight loss, higher PA levels were associated with more improvements in several cardiometabolic variables. The positive effect of higher PA on weight loss maintenance seems in contrast to randomized controlled trials that have not been able to confirm a positive effect of exercise training programmes on weight loss maintenance. This analysis supports the notion that higher self-imposed levels of PA may improve the cardiometabolic risk profile during weight loss and help to maintain weight loss afterwards.

Abstract SP114: Body Image and Sexual Health

Abstract Attention to body image and sexual health after breast cancer are important components of treatment decisions, support through treatment and survivorship care. A high proportion of breast cancer survivors report dissatisfaction with their physical appearance. Body image issues are particularly common among women who undergo mastectomy with or without reconstructive surgery and those who experience weight gain, hair loss from chemotherapy, and other psychosocial issues. Scalp cooling, proactive counseling about potential effects of treatment on weight and physical activity, and psychosocial support through treatment may help to prevent some of these negative effects. Weight loss and subsequent weight maintenance are notoriously difficult to achieve through diet alone, and exercise plays an important role in energy balance through and after treatment. Sexual health is frequently a concern for breast cancer survivors as well, with up to 40% of women reporting issues with sexual interest and 60% with physical sexual function. Issues may arise in the short term following both surgery and chemotherapy, due to factors including lower perceived attractiveness and vaginal dryness. Endocrine therapy with tamoxifen, aromatase inhibitors, and treatment-related amenorrhea or ovarian suppression treatment in premenopausal women are associated with sexual dysfunction. However, a multi-prong approach has been shown to improve such problems. Providers should actively monitor for and manage the consequences of diagnosis and treatment on body image and sexual health in survivors, using psychosocial, behavioral, and pharmacologic tools as needed. Citation Format: A Partridge. Body Image and Sexual Health [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr SP114.

Nondigestible Carbohydrates Affect Metabolic Health and Gut Microbiota in Overweight Adults after Weight Loss

The composition of diets consumed following weight loss (WL) can have a significant impact on satiety and metabolic health. This study was designed to test the effects of including a nondigestible carbohydrate to achieve weight maintenance (WM) following a period of WL. Nineteen volunteers [11 females and 8 males, aged 20-62 y; BMI (kg/m2): 27-42] consumed a 3-d maintenance diet (15%:30%:55%), followed by a 21-d WL diet (WL; 30%:30%:40%), followed by 2 randomized 10-d WM diets (20%:30%:50% of energy from protein:fat:carbohydrate) containing either resistant starch type 3 (RS-WM; 22 or 26g/d for females and males, respectively) or no RS (C-WM) in a within-subject crossover design without washout periods. The primary outcome, WM after WL, was analyzed by body weight. Secondary outcomes of fecal microbiota composition and microbial metabolite concentrations and gut hormones were analyzed in fecal samples and blood plasma, respectively. All outcomes were assessed at the end of each dietary period. Body weight was similar after the RS-WM and C-WM diets (90.7 and 90.8kg, respectively), with no difference in subjectively rated appetite. During the WL diet period plasma ghrelin increased by 36% (P<0.001), glucose-dependent insulinotropic polypeptide (GIP) decreased by 33% (P<0.001), and insulin decreased by 46% (P<0.001), but no significant differences were observed during the RS-WM and C-WM diet periods. Fasting blood glucose was lower after the RS-WM diet (5.59±0.31mmol/L) than after the C-WM diet [5.75±0.49mmol/L; P=0.015; standard error of the difference between the means (SED): 0.09]. Dietary treatments influenced the fecal microbiota composition (R2=0.054, P=0.031) but not diversity. The metabolic benefits, for overweight adults, from WL were maintained through a subsequent WM diet with higher total carbohydrate intake. Inclusion of resistant starch in the WM diet altered gut microbiota composition positively and resulted in lower fasting glucose compared with the control, with no apparent change in appetite. This trial was registered at clinicaltrials.gov as NCT01724411.

Emotion regulation strategies predict weight loss during an inpatient obesity treatment for adolescents.

SummaryObjectiveWeight loss during an inpatient obesity treatment is an important predictor of subsequent weight maintenance. However, psychological factors influencing weight loss are not well established. Psychological models suggest some importance of executive functioning and emotion regulation strategies. Therefore, this study investigated whether these factors predict weight loss during an inpatient obesity treatment and whether this effect holds after controlling for general personal and treatment characteristics.MethodA total of 158 adolescents with diagnosed obesity underwent inpatient obesity treatment at a German rehabilitation clinic. Psychological factors (executive functioning and emotion regulation) were measured at admission and used to predict BMI reduction after treatment completion.ResultsMore frequent use of reappraisal as an emotion regulation strategy, but not suppression or executive functioning, predicted weight loss at the end of the obesity treatment, even after controlling for age, gender, treatment duration, and BMI at admission.ConclusionFunctional emotion regulation strategies, like reappraisal, might offer an additional target for obesity treatment programmes, complementary to the more traditional components of psychoeducation, physical activity, and caloric restriction.

The PROMOTE study (High-protein and resistance-training combination in overweight and obesity) for short-term weight loss and long-term weight maintenance for Chinese people: a protocol for a pilot randomized controlled trial

BackgroundIt is very important for clinicians and dieticians to explore reasonable weight management strategies for obese people that address both short-term weight loss and subsequent weight maintenance. We hypothesized that resistance training combined with a high-protein diet would result in similar short-term weight loss but better long-term weight maintenance than either a conventional low-fat diet control or a high-protein diet alone.Methods/designThis is an 8-week randomized parallel controlled trial followed by a 24-week observational follow-up study. A 48-week supplementary follow-up study will be carried out if necessary. The study will be conducted between June 2019 and October 2020. The 90 overweight or obese participants will be randomly assigned to the conventional low-fat diet group, the high-protein diet group and the high-protein diet and resistance training combination group. Primary outcomes are body weight change at week 8 and week 24 compared with the baseline level.DiscussionHigh-quality research on the effect of a high-protein diet combined resistance training on weight loss and weight maintenance is limited in the Chinese population. Our study will provide a basis for obesity management in China and will promote the development of exercise- and diet-related studies.Trial registrationChinese Clinical Trial Registry, ChiCTR1900023841. Registered on 14 June 2019.

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

IntroductionThe 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. MethodsA total of 24 participants (12f/12 m; age 52.8 ± 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. ResultsAt 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 ± 3.3 to 28.1 ± 2.8 kg/m2, p < .01), body-fat (41.6 ± 6.4 to 35.0 ± 8.0%, p < .01) and insulin resistance (HOMA-IR: 4.0 ± 2.0 to 1.8 ± 0.9, p < .01). During the 22-month weight maintenance period, these parameters gradually increased again (BMI: 29.3 ± 3.8 kg/m2; body-fat: 37.8 ± 9.3%; HOMA-IR: 2.9 ± 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. ConclusionIn 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 registrationThe trial is registered with ClinicalTrials.gov, NCT01777893.

The influence of exercise training dose on fasting acylated ghrelin concentration in older women.

This study investigated if exercise dose affected acylated ghrelin response to exercise training, and how body weight or fat mass changes might affect the responses. Non-obese older women (n = 49) were randomly assigned to 4-month moderate-intensity aerobic exercise of one of two doses (8 or 14kcalkg-1 body weight weekly). Following exercise training, fasting acylated ghrelin concentrations changed differently between the two groups (p for group × time interaction = 0.050). It decreased in the moderate-dose (Cohen's d = 0.52, p = 0.019), but did not change in the low-dose exercise group. Adjustment for weight or fat changes did not affect these results. Therefore, exercise training dose can have specific effects on acylated ghrelin that are not dependent on weight or fat loss. However, whether the different acylated ghrelin changes are associated with differing degree of subsequent weight maintenance worth further investigation.

Associations of Brain Reactivity to Food Cues with Weight Loss, Protein Intake and Dietary Restraint during the PREVIEW Intervention.

The objective was to assess the effects of a weight loss and subsequent weight maintenance period comprising two diets differing in protein intake, on brain reward reactivity to visual food cues. Brain reward reactivity was assessed with functional magnetic resonance imaging in 27 overweight/obese individuals with impaired fasting glucose and/or impaired glucose tolerance (HOMA-IR: 3.7 ± 1.7; BMI: 31.8 ± 3.2 kg/m2; fasting glucose: 6.4 ± 0.6 mmol/L) before and after an 8-week low energy diet followed by a 2-year weight maintenance period, with either high protein (HP) or medium protein (MP) dietary guidelines. Brain reactivity and possible relationships with protein intake, anthropometrics, insulin resistance and eating behaviour were assessed. Brain reactivity, BMI, HOMA-IR and protein intake did not change differently between the groups during the intervention. In the whole group, protein intake during weight maintenance was negatively related to changes in high calorie images>low calorie images (H > L) brain activation in the superior/middle frontal gyrus and the inferior temporal gyrus (p < 0.005, corrected for multiple comparisons). H > L brain activation was positively associated with changes in body weight and body-fat percentage and inversely associated with changes in dietary restraint in multiple reward, gustatory and processing regions (p < 0.005, corrected for multiple comparisons). In conclusion, changes in food reward-related brain activation were inversely associated with protein intake and dietary restraint during weight maintenance after weight loss and positively associated with changes in body weight and body-fat percentage.

An Integrated Understanding of the Molecular Mechanisms of How Adipose Tissue Metabolism Affects Long-term Body Weight Maintenance.

Lifestyle-based weight loss interventions frequently demonstrate long-term inefficiency and weight regain. Identification of underlying mechanisms and predictors to identify subjects who will benefit from lifestyle-based weight loss strategies is urgently required. We analyzed 143 adults of the randomized Maintain trial (Maintain-Adults) after intended weight loss to identify mechanisms contributing to the regulation of body weight maintenance. Unbiased RNA sequencing of adipose and skeletal muscle biopsies revealed fatty acid metabolism as a key pathway modified by weight loss. Variability of key enzymes of this pathway, estimates of substrate oxidation, and specific serum acylcarnitine (AC) species, representing a systemic snapshot of in vivo substrate flux, predicted body weight maintenance (defined as continuous or dichotomized [< or ≥3% weight regain] variable) 18 months after intended weight loss in the entire cohort. Key results were confirmed in a similar randomized controlled trial in 137 children and adolescents (Maintain-Children), which investigated the same paradigm in a pediatric cohort. These data suggest that adaption of lipid utilization in response to negative energy balance contributes to subsequent weight maintenance. Particularly a functional role for circulating ACs, which have been suggested to reflect intracellular substrate utilization, as mediators between peripheral energy stores and control of long-term energy homeostasis was indicated.

Dietary Protein and Energy Balance in Relation to Obesity and Co-morbidities.

Dietary protein is effective for body-weight management, in that it promotes satiety, energy expenditure, and changes body-composition in favor of fat-free body mass. With respect to body-weight management, the effects of diets varying in protein differ according to energy balance. During energy restriction, sustaining protein intake at the level of requirement appears to be sufficient to aid body weight loss and fat loss. An additional increase of protein intake does not induce a larger loss of body weight, but can be effective to maintain a larger amount of fat-free mass. Protein induced satiety is likely a combined expression with direct and indirect effects of elevated plasma amino acid and anorexigenic hormone concentrations, increased diet-induced thermogenesis, and ketogenic state, all feed-back on the central nervous system. The decline in energy expenditure and sleeping metabolic rate as a result of body weight loss is less on a high-protein than on a medium-protein diet. In addition, higher rates of energy expenditure have been observed as acute responses to energy-balanced high-protein diets. In energy balance, high protein diets may be beneficial to prevent the development of a positive energy balance, whereas low-protein diets may facilitate this. High protein-low carbohydrate diets may be favorable for the control of intrahepatic triglyceride IHTG in healthy humans, likely as a result of combined effects involving changes in protein and carbohydrate intake. Body weight loss and subsequent weight maintenance usually shows favorable effects in relation to insulin sensitivity, although some risks may be present. Promotion of insulin sensitivity beyond its effect on body-weight loss and subsequent body-weight maintenance seems unlikely. In conclusion, higher-protein diets may reduce overweight and obesity, yet whether high-protein diets, beyond their effect on body-weight management, contribute to prevention of increases in non-alcoholic fatty liver disease NAFLD, type 2 diabetes and cardiovascular diseases is inconclusive.

Effects of replacing diet beverages with water on weight loss and weight maintenance: 18-month follow-up, randomized clinical trial.

Beneficial effects of replacing diet beverages (DBs) with water on weight loss, during a 24-week hypoenergetic diet were previously observed. However, it is not known whether this difference is sustained during a subsequent 12-month weight maintenance period. To evaluate effects of replacing DBs with water on body weight maintenance over a 12-month period in participants who undertook a 6-month weight loss plan. Seventy-one obese and overweight adult women (body mass index (BMI): 27-40 kg m-2; age: 18-50 years) who usually consumed DBs in their diet were randomly assigned to either substitute water for DBs (water group: 35) or continue drinking DBs five times per week (DBs group: 36) after their lunch for the 6-month weight loss intervention and subsequent 12-month weight maintenance program. A total of 71 participants who were randomly assigned were included in the study by using an intention-to-treat analysis. Greater additional weight loss (mean±s.d.) in the water group was observed compared with the DBs group after the 12-month follow-up period (-1.7±2.8 vs -0.1±2.7 kg, P=0.001). BMI decreased more in the water group than in the DBs group (-0.7±1 vs -0.05±1.1 kg m-2, P=0.003). There was also a greater reduction in fasting insulin levels (-0.5±1.4 vs -0.02±1.5 mmol l-1, P=0.023), better improvement in homeostasis model assessment of insulin resistance (-0.2±0.4 vs -0.1±0.3, P=0.013) and a greater decrease in 2-h postprandial plasma glucose (-0.2±0.3 vs -0.1±0.3 mmol l-1, P<0.001) in the water group compared with the DBs over the 12-month weight maintenance period. Replacement of DBs with water after the main meal in women who were regular users of DBs may cause further weight reduction during a 12-month weight maintenance program. It may also offer benefits in carbohydrate metabolism including improvement of insulin resistance over the long-term weight maintenance period.

Caloric Restriction in Older Adults-Differential Effects of Weight Loss and Reduced Weight on Brain Structure and Function.

Dietary modifications such as caloric restriction (CR) have been suggested as a means to improve memory and prevent age-related decline. However, it is unclear whether those effects remain stable over time or are related specifically to negative energy balance during the weight loss phase of CR. Using a randomized interventional design, we investigated changes in recognition memory and neural correlates in postmenopausal obese women (n = 19): 1) after intense weight loss in the course of a 12-week low-caloric diet (reduced body weight and negative energy balance) and 2) after having sustained the reduced weight over 4 more weeks (reduced body weight, but energy balance equilibrium). Participants were contrasted to a control group (n = 18) instructed not to change dietary habits. In the CR group, we found improved recognition memory, paralleled by increased gray matter volume in inferior frontal gyrus and hippocampus, and augmented hippocampal resting-state functional connectivity to parietal areas. Moreover, effects were specific for transient negative energy balance and could not be detected after subsequent weight maintenance. Our data demonstrate for the first time in humans that beneficial effects of CR on brain structure and function are due to weight loss rather than an overall reduced weight.

System model network for adipose tissue signatures related to weight changes in response to calorie restriction and subsequent weight maintenance.

Nutrigenomics investigates relationships between nutrients and all genome-encoded molecular entities. This holistic approach requires systems biology to scrutinize the effects of diet on tissue biology. To decipher the adipose tissue (AT) response to diet induced weight changes we focused on key molecular (lipids and transcripts) AT species during a longitudinal dietary intervention. To obtain a systems model, a network approach was used to combine all sets of variables (bio-clinical, fatty acids and mRNA levels) and get an overview of their interactions. AT fatty acids and mRNA levels were quantified in 135 obese women at baseline, after an 8-week low calorie diet (LCD) and after 6 months of ad libitum weight maintenance diet (WMD). After LCD, individuals were stratified a posteriori according to weight change during WMD. A 3 steps approach was used to infer a global model involving the 3 sets of variables. It consisted in inferring intra-omic networks with sparse partial correlations and inter-omic networks with regularized canonical correlation analysis and finally combining the obtained omic-specific network in a single global model. The resulting networks were analyzed using node clustering, systematic important node extraction and cluster comparisons. Overall, AT showed both constant and phase-specific biological signatures in response to dietary intervention. AT from women regaining weight displayed growth factors, angiogenesis and proliferation signaling signatures, suggesting unfavorable tissue hyperplasia. By contrast, after LCD a strong positive relationship between AT myristoleic acid (a fatty acid with low AT level) content and de novo lipogenesis mRNAs was found. This relationship was also observed, after WMD, in the group of women that continued to lose weight. This original system biology approach provides novel insight in the AT response to weight control by highlighting the central role of myristoleic acid that may account for the beneficial effects of weight loss.

Maintenance of energy expenditure on high-protein vs. high-carbohydrate diets at a constant body weight may prevent a positive energy balance

Relatively high-protein diets are effective for body weight loss, and subsequent weight maintenance, yet it remains to be shown whether these diets would prevent a positive energy balance. Therefore, high-protein diet studies at a constant body weight are necessary. The objective was to determine fullness, energy expenditure, and macronutrient balances on a high-protein low-carbohydrate (HPLC) diet compared with a high-carbohydrate low-protein (HCLP) diet at a constant body weight, and to assess whether effects are transient or sustained after 12 weeks. A randomized parallel study was performed in 14 men and 18 women [mean ± SD age: 24 ± 5 y; BMI (in kg/m(2)): 22.8 ± 2.0] on diets containing 30/35/35 (HPLC) or 5/60/35 (HCLP) % of energy from protein/carbohydrate/fat. Significant interactions between dietary intervention and time on total energy expenditure (TEE) (P = 0.013), sleeping metabolic rate (SMR) (P = 0.040), and diet-induced thermogenesis (DIT) (P = 0.027) appeared from baseline to wk 12. TEE was maintained in the HPLC diet group, while it significantly decreased throughout the intervention period in the HCLP diet group (wk 1: P = 0.002; wk 12: P = 0.001). Energy balance was maintained in the HPLC diet group, and became positive in the HCLP diet group at wk 12 (P = 0.008). Protein balance varied directly according to the amount of protein in the diet, and diverged significantly between the diets (P = 0.001). Fullness ratings were significantly higher in the HPLC vs. the HCLP diet group at wk 1 (P = 0.034), but not at wk 12. Maintenance of energy expenditure on HPLC vs. HCLP diets at a constant body weight may prevent development of a positive energy balance, despite transiently higher fullness. The study was registered on clinicaltrials.gov with Identifier: NCT01551238.