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The observation that 64% of English adults are overweight or obese despite a rising prevalence in weight-loss attempts suggests our understanding of energy balance is fundamentally flawed. Weight-loss is induced through a negative energy balance; however, we typically view weight change as a static function, in that energy intake and energy expenditure are independent variables, resulting in a fixed rate of weight-loss assuming a constant energy deficit. Such static modelling provides the basis for the clinical assumption that a 14644 kJ (3500 kcal) deficit translates to a 1 lb weight-loss. However, this ‘3500 kcal (14644 kJ) rule’ is consistently shown to significantly overestimate weight-loss. Static modelling disregards obligatory changes in energy expenditure associated with the loss of metabolically active tissue, i.e. skeletal muscle. Additionally, it disregards the presence of adaptive thermogenesis, the underfeeding-associated fall in resting energy expenditure beyond that caused by loss of fat-free mass. This metabolic manipulation of energy expenditure is observed from the onset of energy restriction to maintain weight at a genetically pre-determined set point. As a result, the observed magnitude of weight-loss is disproportionally less, followed by earlier weight plateau, despite strict compliance to a dietary intervention. By simulating dynamic changes in energy expenditure associated with underfeeding, mathematical modelling may provide a more accurate method of weight-loss prediction. However, accuracy at an individual level is limited due to difficulty estimating energy requirements, physical activity and dietary intake in free-living individuals. In the present paper, we aim to outline the contribution of dynamic changes in energy expenditure to weight-loss resistance and weight plateau.

High-resolution mass flux measurements of an electrospray plume are reported at high (>30$$^{\circ }$$ ∘ ) angles, which are relevant to direct impingement of downstream electrodes. Interrogation of the plume edge greatly reduces uncertainty in electrospray device lifetime estimation related to mass flux to electrode surfaces. An angularly-actuated Thermoelectric Quartz Crystal Microbalance (TQCM) provides resolution down to $$\sim$$ ∼ 2 pg cm$$^{-2}$$ - 2 s$$^{-1}$$ - 1 , allowing the highest resolution mass flux measurements of an electrospray plume to be reported herein. In-situ microscopy of the electrospray meniscus revealed changes to the electrode lines-of-sight of approximately 2°–3° due to the increasing meniscus tip height with beam current. Using the TQCM measurements and previous QCM results, a data-driven model is proposed for estimating electrode impingement as a function of beam current and aperture line-of-sight, which quantitatively captures the rapid increase in mass flux at higher beam currents or at low angles. The results show it is possible to guarantee negligible electrode impingement within a specified range of throttle levels.

There are two proven dietary approaches to shift type 2 diabetes (T2D) into remission: low energy diets (LED) and low carbohydrate diets (LCD). These approaches differ in their rationale and application yet both involve carbohydrate restriction, either as an explicit goal or as a consequence of reducing overall energy intake. The aims of this systematic review were to identify, characterise and compare existing clinical trials that utilised ‘low carbohydrate’ interventions with differing energy intakes. Electronic databases CENTRAL, CINAHL, Embase, MEDLINE and Scopus were searched to identify controlled clinical trials in adults with T2D involving low carbohydrate intake (defined as ad libitum) energy intakes produced clinically significant weight loss and reduction in HbA1c at study end-points. Trials that restricted energy intake were not superior to those that allowed ad libitum low carbohydrate feeding at 12 and 24 months. An association was observed across studies between average weight loss and reduction in HbA1c, which strengthened with trial length, indicating that sustained weight loss is key to T2D remission. Further research is needed to specifically ascertain the weight-independent effects of carbohydrate restriction on glycemic control in T2D.Graphical abstract

Hazardous alcohol consumption is ranked above illicit drug use with regards to health deterioration and social and economic burden. This study sought to clarify the factors influencing alcohol consumption and its prevalence in young adults. Demographics, alcohol consumption and lifestyle information were gathered via anonymous questionnaires during 2011&ndash, 2019, crossing Reading, Surrey and Farnborough universities, UK. Controlling for confounders, a multinomial logistic regression was performed using SAS&reg, 9.4 software. A total of 1440 students (43.5% males, 56.5% females, 54.4% Caucasians) with a mean (SD) age of 19.9 (2.73) were included. Among them, 68.9% consumed alcohol frequently and 31.7% had &ge, 12 units/week. Statistical analysis revealed that males consumed twice more alcohol than females, odds ratio (OR) 1.67 (95% confidence interval (CI) = 1.34&ndash, 2.09), p-value &lt, 0.01. Caucasians consumed up to five times more alcohol than other ethnicities, OR 4.55 (3.57&ndash, 5.56), p-value &lt, 0.01. Smokers consumed three times more alcohol than non-smokers, OR 2.69 (1.82, 3.99), p-value &lt, 0.01. In general, the levels of alcohol consumption were positively associated with the levels of physical activity, OR 2.00 (1.17&ndash, 3.42), p-value &lt, 0.05 and negatively associated with recreational sedentary screen-time activities in males, OR 0.31 (0.12&ndash, 0.86), p-value = 0.03. Focusing alcohol interventions toward Caucasians, smokers and physically active students, particularly males, may guide university strategies to reduce alcohol-related societal harm and risks of morbidity and mortality.

Background Medical science students represent valuable labour resources for better future medicine and medical technology. However, little attention was given to the health and well-being of these early career medical science professionals. The aim of this study is to investigate the impact of lifestyle components on cardiorespiratory fitness and heart rate recovery measured after moderate exercise in this population. Methods Volunteers without documented medical condition were recruited randomly and continuously from the first-year medical science students during 2011–2014 at the University of Surrey, UK. Demographics and lifestyle components (the levels of smoking, alcohol intake, exercise, weekend outdoor activity and screen-time, daily sleep period, and self-assessment of fitness) were gathered through pre-exercise questionnaire. Cardiorespiratory fitness (VO2max) and heart rate recovery were determined using Åstrand–Rhyming submaximal cycle ergometry test. Data were analysed using SPSS version 25. Results Among 614 volunteers, 124 had completed both lifestyle questionnaire and the fitness test and were included for this study. Within 124 participants (20.6 ± 4 years), 46.8% were male and 53.2% were female, 11.3% were overweight and 8.9% were underweight, 8.9% were current smokers and 33.1% consumed alcohol beyond the UK recommendation. There were 34.7% of participants admitted to have 2max distribution was inversely associated with heart rate recovery at 3 min and both values were significantly correlated with the levels of exercise, self-assessed fitness and BMI. Participants who had 2max and heart rate recovery than their peers. Conclusion One in three new medical science students were physically inactive along with compromised cardiorespiratory fitness and heart rate recovery, which put them at risk of cardiometabolic diseases. Promoting healthy lifestyle at the beginning of career is crucial in keeping medical science professionals healthy.

The University of Surrey was recently awarded the Queen’s Anniversary Prize in recognition of excellence in teaching and research within food and nutrition. This chapter describes a pedagogic study whereby a student and staff researcher worked in partnership to ascertain student experiences of the nutrition curriculum in relation to threshold concepts (five core competencies required by the professional body, the Association for Nutrition) employing the use of focus groups. Along with identifying the strengths and weaknesses of the present curriculum, this project also highlighted how crucial it is to include the student voice, and their appreciation of the curriculum standards, in the curriculum design process.

Intermittent energy restriction (IER) has become the subject of considerable scientific interest as a potential dietary approach for weight-loss and improving cardiometabolic health. This approach involves intermittent periods of total or partial energy restriction (ER) alternated with non-restricted intake, and has been studied in rodent and human populations. This review aims to provide an overview of the IER literature to date, with a specific focus on its effects on cardiometabolic health indices in rodents and humans. Current evidence from studies in rodents and humans suggests that IER is capable of promoting weight-loss and/or favourably influencing an array of cardiometabolic health indices, with equal or greater efficacy than conventional continuous ER approaches. Putative mechanisms include the effects of IER on adipose tissue physiology, stress resistance and fat distribution within visceral and intra-hepatic sites. However, a large proportion of this mechanistic evidence is limited to indirect observations and/or has come from rodent studies requiring translation into humans. Furthermore, whilst there is some indication that total IER and the array of partial IER protocols which have been developed may elicit distinct biological effects, our knowledge around this is limited as only a small number of rodent studies have directly addressed this. Ultimately, whilst much remains to be learned about IER, including its mechanisms of action and long-term efficacy, the positive findings to date serve to highlight promising avenues for future research.

Two intermittent fasting variants, intermittent energy restriction (IER) and time-restricted feeding (TRF), have received considerable interest as strategies for weight-management and/or improving metabolic health. With these strategies, the pattern of energy restriction and/or timing of food intake are altered so that individuals undergo frequently repeated periods of fasting. This review provides a commentary on the rodent and human literature, specifically focusing on the effects of IER and TRF on glucose and lipid metabolism. For IER, there is a growing evidence demonstrating its benefits on glucose and lipid homeostasis in the short-to-medium term; however, more long-term safety studies are required. Whilst the metabolic benefits of TRF appear quite profound in rodents, findings from the few human studies have been mixed. There is some suggestion that the metabolic changes elicited by these approaches can occur in the absence of energy restriction, and in the context of IER, may be distinct from those observed following similar weight-loss achieved via modest continuous energy restriction. Mechanistically, the frequently repeated prolonged fasting intervals may favour preferential reduction of ectopic fat, beneficially modulate aspects of adipose tissue physiology/morphology, and may also impinge on circadian clock regulation. However, mechanistic evidence is largely limited to findings from rodent studies, thus necessitating focused human studies, which also incorporate more dynamic assessments of glucose and lipid metabolism. Ultimately, much remains to be learned about intermittent fasting (in its various forms); however, the findings to date serve to highlight promising avenues for future research.

Abdominal obesity, more specifically increased intra-abdominal adipose tissue, is strongly associated with increased risk of metabolic disease. Bioelectrical impedance analysis (BIA) has been proposed as a potential method of determining individual abdominal fat compartments in the form of the commercially available ViScan measurement system (Tanita Corporation), but it has yet to be independently validated. The objective of this study was to analyse the validity of the ViScan to assess adult abdominal adiposity across a range of body fatness.This was a cross-sectional study with 74 participants (40 females and 34 males with body mass index (BMI) between 18.5 and 39.6 kg/m(2)). Total abdominal adipose tissue, subcutaneous abdominal adipose tissue (SAAT) and intra-abdominal adipose tissue (IAAT) were measured by magnetic resonance imaging (MRI). In addition, intra-hepatocellular lipid was obtained by magnetic resonance spectroscopy. Estimates of abdominal adiposity (total and compartmental) were obtained from BIA and anthropometry.ViScan-derived percentage trunk fat strongly and significantly related with total abdominal adipose tissue and SAAT in both lean and overweight/obese individuals, and categorized individuals reliably in terms of total abdominal fat. ViScan-derived 'visceral' fat correlated significantly with IAAT but the strength of this relationship was much weaker in overweight/obese individuals, particularly those with higher SAAT, leading to less reliable classification of individuals for IAAT.The ViScan may serve as a useful tool for predicting total abdominal fat, but prediction of visceral fat (IAAT) may be limited, especially in abdominally obese individuals.

The intermittent energy restriction (IER) approach to weight loss involves short periods of substantial (75–100 %) energy restriction (ER) interspersed with normal eating. This study aimed to characterise the early metabolic response to these varying degrees of ER, which occurs acutely and prior to weight loss. Ten (three female) healthy, overweight/obese participants (36 (SEM 5) years; 29·0 (sem 1·1) kg/m2) took part in this acute three-way cross-over study. Participants completed three 1-d dietary interventions in a randomised order with a 1-week washout period: isoenergetic intake, partial 75 % ER and total 100 % ER. Fasting and postprandial (6-h) metabolic responses to a liquid test meal were assessed the following morning via serial blood sampling and indirect calorimetry. Food intake was also recorded for two subsequent days of ad libitum intake. Relative to the isoenergetic control, postprandial glucose responses were increased following total ER (+142 %; P=0·015) and to a lesser extent after partial ER (+76 %; P=0·051). There was also a delay in the glucose time to peak after total ER only (P=0·024). Both total and partial ER interventions produced comparable reductions in postprandial TAG responses (−75 and −59 %, respectively; both PP=0·015). Resting and meal-induced thermogenesis were not significantly affected by either ER intervention. In conclusion, our data demonstrate the ability of substantial ER to acutely alter postprandial glucose–lipid metabolism (with partial ER producing the more favourable overall response), as well as incomplete energy-intake compensation amongst overweight/obese participants. Further investigations are required to establish how metabolism adapts over time to the repeated perturbations experienced during IER, as well as the implications for long-term health.

Objective: To investigate methodological precision of air displacement plethysmography for assessment of body composition in a heterogenous sample of adults. Design: Accuracy of volume measurements by air displacement plethysmography (ADP) for a range of known volumes was ascertained. Repeated measurements of body volume, lung volume, and derived body composition using the BODPOD measurement system were performed. Influence of surface area estimation on ADP measurement was investigated as a possible source of variation. Setting: Clinical Nutrition Laboratory, School of Health & Sports Science, University of North London, London, UK. Subjects: One hundred and two healthy subjects (57 women, 45 men) who ranged in age between 16 and 55 y and in BMI (kg/m2) between 17.8 and 41.9. Study design: Cross-sectional study of healthy adults for comparison with previous studies. Repeat measurements of raw body volume, lung volume and % body fat (BF) by ADP were all performed on the same day. Results: From the range of known volumes a marked increase in the CV and a significantly greater measurement error were found at volumes below 40 l (P=0.04). Repeat measurements of raw body volume in human subjects resulted in a technical error equivalent to 0.8% BF. There was no significant difference found between measured and predicted lung volume and the 95% confidence interval for difference was only 0.3% BF. Repeat measurements of lung volume in our subset resulted in a technical error equivalent to 0.5% BF. Although body surface area estimation only accounted for variation in % BF of 0.1%, the extent of variation appeared to be governed by leanness (P

Digital Speckle Radiography (DSR), a technique allowing measurement of the full field displacement maps in a plane within an opaque material, is used to follow the temporal progression of a long‐rod (100 mm long, 10 mm diameter) penetrating a granular sample at a variety of rates. Quasi‐static rates of 1.5 mm/min are achieved using an Instron machine, 5 m/s is achieved using a drop‐weight and velocities between 10 and 200 m/s are achieved using a light gas gun. These experiments are carried out using a series of time delayed flash x‐ray images analysed with an optimised Digital Image Cross Correlation algorithm (DICC). The subsequent data sheds considerable light on the response of granular materials to penetration at a variety of rates. Particularly, a large difference in the response of the material between quasi‐static and dynamic rates is observed.

The purpose of this study was to determine calcaneal broadband ultrasound attenuation (BUA) of marathon race participants and compare this information with previously obtained normative data. BUA was assessed using the McCue CUBA clinical device in 217 male and 184 female runners, aged 20-93 yr, participating in the 2004 Flora London Marathon. The normative data included 267 men and 334 women, aged 20-80 yr. A significantly higher mean BUA (p0.001) was observed for all the men (91.2 dB/MHz, standard deviation [SD] 18.2 dB/MHz) in the study compared to the women (81.6 dB/MHz, SD 17.0 dB/MHz) and for the marathon runners compared to the nonrunners (p0.001) among men (97.2dB/MHz, SD 17.6 dB/MHz and 87.7 dB/MHz, SD 17.6 dB/MHz, respectively) and women (89.2dB/MHz, SD 14.2dB/MHz and 77.4dB/MHz, SD 17.0 dB/MHz, respectively). A significant decline in BUA with age was observed in all males and females, with the males starting from a higher baseline and with the rate of decline significantly ameliorated by marathon training (from -0.35 to -0.25 dB/MHz per year in men and -0.51 to -0.15 dB/MHz per year in women). This study provides observational evidence in support of the potential benefits of weight-bearing exercise, such as marathon training and running, on BUA of the calcaneus, an index of bone mineral density.

Appetite control (i.e. control of energy intake) is important for weight maintenance. Moreover, exercise contributes to the most variable component of energy expenditure but its impact is beyond the energy cost of exercise including physiological, behavioural, and appetite effects (Spiegelman and Flier JS. Cell . 2001; 104 :531–43). Exercise is known to acutely influence effect appetite but evidence as to the independent effect of intensity is lacking (Martins et al. , J Clin Endocrinol Metab . 2010; 95 :1609–16). This study investigated the role of exercise intensity on appetite, energy intake (EI), energy expenditure and subjective measures of appetite. One hour after a standardised breakfast, 30 healthy normal- weight volunteers 30 lean and 10 obese. Subjects undertook either 8 repeated 60 second bouts of cycling at 95% VO2 max (high intensity) or 30 min of continuous cycling, at a fixed cadence, equivalent to 50% of the participant’s VO2 max (low intensity) in a randomised crossover design. Satiety was assessed subjectively throughout the study using visual analogue scales. Ad libitum intake of a pasta meal was measured at the end (3-h post-breakfast). No significant effect of exercise was observed on the ad libitum meal or 24 h energy intake post-exercise. For lean group, HI significantly increased energy expenditure compared to LI post-exercise (p = .001) with a significant difference in fat oxidation level. No significant differences were observed in energy intake of fat for 2 days post-exercise between two intensities for both groups. In conclusion, there are mechanisms and consequences of exercise in short and long-term appetite control; however, these mechanisms warrant further explanation. These results support the need for future research in to the role of in regulation energy balance, especially for obese people.