Background & aim The aim of this study was to describe a decrease in resting energy expenditure during weight loss that is larger than expected based on changes in body composition, called adaptive thermogenesis (AT), in overweight and obese older adults. Methods Multiple studies were combined to assess AT in younger and older subjects. Body composition and resting energy expenditure (REE) were measured before and after weight loss. Baseline values were used to predict fat free mass and fat mass adjusted REE after weight loss. AT was defined as the difference between predicted and measured REE after weight loss. The median age of 55 y was used as a cutoff to compare older with younger subjects. The relation between AT and age was investigated using linear regression analysis. Results In this study 254 (M = 88, F = 166) overweight and obese subjects were included (BMI: 31.7 ± 4.4 kg/m2, age: 51 ± 14 y). The AT was only significant for older subjects (64 ± 185 kcal/d, 95% CI [32, 96]), but not for younger subjects (19 ± 152 kcal/d, 95% CI [−9, 46]). The size of the AT was significantly higher for older compared to younger adults (β = 47, p = 0.048), independent of gender and type and duration of the weight loss program. Conclusions We conclude that adaptive thermogenesis is present only in older subjects, which might have implications for weight management in older adults. A reduced energy intake is advised to counteract the adaptive thermogenesis.
RATIONALE: Currently there is no consensus on protein requirements for obese older adults during weight loss. Here we explore the potential use of a new method for assessment of protein requirements based on changes in appendicular muscle mass during weight loss.METHODS: 60 obese older adults were subjected to 13 wk weight loss program, including hypocaloric diet and resistance training. Assessment of appendicular muscle mass was performed by DXA at baseline and after 13 wk challenge period, and the difference calculated as muscle mass change. Protein intake (g/kg body weight and g/kg fat free mass (FFM)) at 13wks was used as marker of protein intake during 13 wk period. 30 subjects received 10 times weekly 20 g protein supplement throughout the 13 week hypocaloric phase which is included in the calculation of total protein intake. Receiver operating characteristic (ROC) curve analysis was used to explore the optimal cutoff point for protein intake (g/kg) versus increase in appendicular muscle mass of more than 250 g over 13 wks (y/n). Subsequently, logistic regression analysis was performed for protein intake cutoff and muscle mass accretion, adjusted for sex, age, baseline BMI, and training compliance.RESULTS: ROC curve analysis provided a protein intake level per day of 1.2 g/kg bw and 1.9 g/kg FFM as cutoff point. Presence of muscle mass accretion during 13 wk challenge period was significantly higher with protein intake higher than 1.2 g/kg bw (OR 5.4, 95%CI 1.4-20.6, p = 0.013) or higher than 1.9 g/kg FFM (OR 8.1, 95%CI 2.1-31.9, p = 0.003). Subjects with a protein intake higher than 1.2 g/kg had significantly more often muscle mass accretion, compared to subjects with less protein intake (10/14 (72%) vs 15/46 (33%), p = 0.010). For 1.9 g/kg FFM this was 70% vs 28% (p = 0.002).CONCLUSION: This exploratory study provided a level of at least 1.2 g/kg body weight or 1.9 g/kg fat free mass as optimal daily protein intake for obese older adults under these challenged conditions of weight loss, based on muscle mass accretion during the challenge.TRIAL REGISTRATION: Dutch Trial Register under number NTR2751.
OBJECTIVES: Patients with head and neck cancer (HNC) frequently encounter weight loss with multiple negative outcomes as a consequence. Adequate treatment is best achieved by early identification of patients at risk for critical weight loss. The objective of this study was to detect predictive factors for critical weight loss in patients with HNC receiving (chemo)radiotherapy ((C)RT).MATERIALS AND METHODS: In this cohort study, 910 patients with HNC were included receiving RT (±surgery/concurrent chemotherapy) with curative intent. Body weight was measured at the start and end of (C)RT. Logistic regression and classification and regression tree (CART) analyses were used to analyse predictive factors for critical weight loss (defined as >5%) during (C)RT. Possible predictors included gender, age, WHO performance status, tumour location, TNM classification, treatment modality, RT technique (three-dimensional conformal RT (3D-RT) vs intensity-modulated RT (IMRT)), total dose on the primary tumour and RT on the elective or macroscopic lymph nodes.RESULTS: At the end of (C)RT, mean weight loss was 5.1±4.9%. Fifty percent of patients had critical weight loss during (C)RT. The main predictors for critical weight loss during (C)RT by both logistic and CART analyses were RT on the lymph nodes, higher RT dose on the primary tumour, receiving 3D-RT instead of IMRT, and younger age.CONCLUSION: Critical weight loss during (C)RT was prevalent in half of HNC patients. To predict critical weight loss, a practical prediction tree for adequate nutritional advice was developed, including the risk factors RT to the neck, higher RT dose, 3D-RT, and younger age.
While the creation of an energy deficit (ED) is required for weight loss, it is well documented that actual weight loss is generally lower than what expected based on the initially imposed ED, a result of adaptive mechanisms that are oppose to initial ED to result in energy balance at a lower set-point. In addition to leading to plateauing weight loss, these adaptive responses have also been implicated in weight regain and weight cycling (add consequences). Adaptions occur both on the intake side, leading to a hyperphagic state in which food intake is favored (elevated levels of hunger, appetite, cravings etc.), as well as on the expenditure side, as adaptive thermogenesis reduces energy expenditure through compensatory reductions in resting metabolic rate (RMR), non-exercise activity expenditure (NEAT) and the thermic effect of food (TEF). Two strategies that have been utilized to improve weight loss outcomes include increasing dietary protein content and increasing energy flux during weight loss. Preliminary data from our group and others demonstrate that both approaches - especially when combined - have the capacity to reduce the hyperphagic response and attenuate reductions in energy expenditure, thereby minimizing the adaptive mechanisms implicated in plateauing weight loss, weight regain and weight cycling. Past research has largely focused on one specific component of energy balance (e.g. hunger or RMR) rather than assessing the impact of these strategies on all components of energy balance. Given that all components of energy balance are strongly connected with each other and therefore can potentially negate beneficial impacts on one specific component, the primary objective of this application is to use a comprehensive approach that integrates all components of energy balance to quantify the changes in response to a high protein and high energy flux, alone and in combination, during weight loss (Fig 1). Our central hypothesis is that a combination of high protein intake and high energy flux will be most effective at minimizing both metabolic and behavioral adaptations in several components of energy balance such that the hyperphagic state and adaptive thermogenesis are attenuated to lead to superior weight loss results and long-term weight maintenance.
The postdoc candidate, Sondos Saad, will strengthen connections between research groups Asset Management(AM), Data Science(DS) and Civil Engineering bachelor programme(CE) of HZ. The proposed research aims at deepening the knowledge about the complex multidisciplinary performance deterioration prediction of turbomachinery to optimize cleaning costs, decrease failure risk and promote the efficient use of water &energy resources. It targets the key challenges faced by industries, oil &gas refineries, utility companies in the adoption of circular maintenance. The study of AM is already part of CE curriculum, but the ambition of this postdoc is that also AM principles are applied and visible. Therefore, from the first year of the programme, the postdoc will develop an AM material science line and will facilitate applied research experiences for students, in collaboration with engineering companies, operation &maintenance contractors and governmental bodies. Consequently, a new generation of efficient sustainability sensitive civil engineers could be trained, as the labour market requires. The subject is broad and relevant for the future of our built environment being more sustainable with less CO2 footprint, with possible connections with other fields of study, such as Engineering, Economics &Chemistry. The project is also strongly contributing to the goals of the National Science Agenda(NWA), in themes of “Circulaire economie en grondstoffenefficiëntie”,”Meten en detecteren: altijd, alles en overall” &”Smart Industry”. The final products will be a framework for data-driven AM to determine and quantify key parameters of degradation in performance for predictive AM strategies, for the application as a diagnostic decision-support toolbox for optimizing cleaning &maintenance; a portfolio of applications &examples; and a new continuous learning line about AM within CE curriculum. The postdoc will be mentored and supervised by the Lector of AM research group and by the study programme coordinator(SPC). The personnel policy and job function series of HZ facilitates the development opportunity.
De verplichting in de Binnenvaart om haar emissies te reduceren leidt tot grote uitdagingen in de sector, omdat nieuwe technologie in bestaande schepen tot problemen leidt en vaak een te grote investering vraagt. VIV, de branchevereniging van inbouw-, reparatie- en revisiebedrijven, heeft zich uitgesproken voor het gebruik van hernieuwbare methanol. Het ontbreekt de bedrijven echter aan kennis en vaardigheid over de conversie van een bestaande dieselmotor naar hernieuwbare methanol. De methanol industrie, verenigd in het Methanol Institute, zet zich in voor het gebruik van methanol in de scheepvaart. In de Zeevaart is al ervaring opgedaan met hernieuwbare methanol, maar de schaal en technologie verschilt met die in onze Binnenvaart. VIV en het Methanol Institute hebben de HAN benaderd met de vraag om de kennis en vaardigheid in gebruik van hernieuwbare methanol in scheepsmotoren te vergroten. De HAN beantwoordt deze marktvraag in 4 werkpakketten waar het draait om de retrofit conversie van een bestaande binnenvaartaandrijving, op een praktisch toepasbare manier. Ze maakt hier een vertaalslag van de wetenschap en kennis bij grote zeevaartmotoren, naar het binnenvaart-MKB. Dit gebeurt door te onderzoeken binnen welke kaders, en met welke indicatoren tijdens het afstellen van een onderzoeksmotor, een optimale methanol dual-fuel motor opgezet kan worden. Het hoofddoel is het verhogen van de kennis en vaardigheid over dual-fuel motoren op Hernieuwbare Methanol in de reparatie- en revisiesector. Het Schoon Schip project combineert de opgedane kennis met kennis uit de academische wereld, en de motorervaring van alle partners, om tot een betrouwbare toepassing van methanol in de binnenvaart te komen. Het gaat er om tot een werkende praktijkoplossing te komen voor het gebruik van hernieuwbare methanol in de bestaande vloot van 12.000 binnenvaartschepen.
