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This perspective is a continuation of a conversation started during “Reimagining Food, Food Systems, and Food Studies,” a plenary session in which we, the authors, participated at the eighteenth annual assembly of the Canadian Association for Food Studies (CAFS). Assessing current opportunities and limitations for food studies in Canada from our perspectives as emerging scholars, the CAFS panel presented our individual and collective proposals for evolving the field. This article builds on the resonances and dissonances from our discussion to craft a provisional “recipe” for reimagining food studies. Recognizing the shortcomings of the format in terms of its prescriptive connotations, we position recipes not as rigid guidelines for achieving predefined outcomes, but as creative models for generating improvisations. We begin with an overview of the ingredients that have come together to create food studies in Canada. Next, we offer some revisions in the margins of this recipe based on the work in which we are engaged as food scholars and practitioners. Finally, we consider next steps for the work of evolving the field, and we invite readers to share in this exchange. Overall, we observe and participate in an unfinished trajectory that extends from previous questions on why food studies should exist and what food studies is, to consider more deeply how food studies could be done.

Abstract Variations in physical activity energy expenditure can make accurate prediction of total energy expenditure (TEE) challenging. The purpose of the present study was to determine the accuracy of available equations to predict TEE in individuals varying in physical activity (PA) levels. TEE was measured by DLW in 56 adults varying in PA levels which were monitored by accelerometry. Ten different models were used to predict TEE and their accuracy and precision were evaluated, considering the effect of sex and PA. The models generally underestimated the TEE in this population. An equation published by Plucker was the most accurate in predicting the TEE in our entire sample. The Pontzer and Vinken models were the most accurate for those with lower PA levels. Despite the levels of accuracy of some equations, there were sizable errors (low precision) at an individual level. Future studies are needed to develop and validate these equations.

Abstract Background Optimal management of voluntary energy expenditure is crucial to the survival and reproductive success of wild animals. Nevertheless, a growing appreciation of inter-individual variation in the internal state driving movement suggests that individuals may follow different, yet equally optimal tactics under the same environmental conditions. However, few studies in wild populations have investigated the occurrence and demographic context of different contemporaneous energetic expenditure tactics. Here, we explore this neglected aspect of energy budgeting in order to determine the effect of life-history traits such as age and reproductive status on the co-occurrence of different energy-budgeting tactics in wild populations. Methods We investigated inter-individual heterogeneity in energy expenditure within a wild population of European badgers (Meles meles) by quantifying individual overall dynamic body acceleration (ODBA, from tri-axial accelerometry collars) and total daily energy expenditure (DEE, from doubly-labelled water) during 6–9 day deployments and dosing periods over six different seasons (spring, summer, and autumn) in 2018–2019. We obtained ODBA values for 41 deployments (24 unique badgers) and DEE measurements for 41 dosings (22 unique badgers). We then evaluated correlations between these energetic metrics and computed individual ratios of ODBA/DEE as a proxy for the proportion of total energy spent on activity. We measured the impact of alternative ODBA/DEE ratios on body condition, and use survival models constructed using 29 years of demographic data from the same population to situate body-condition changes in the context of age and reproductive status. Results Both ODBA and DEE were highly variable between individuals and exhibited season-specific relationships with individual body condition and life-history factors. DEE scaled allometrically with body weight, but only in summer and autumn; post-reproductive female badgers were lighter than other badgers during the spring but expended on average 350 kJ/day more than predicted from allometric scaling. Older badgers expended significantly less energy on movement during the summer than did younger adults. The ratio of ODBA to DEE (OD) provides a measure of proportional investment into movement. This ratio correlated more significantly with next-season body condition than either energetic metric did independently. However, the majority of individuals with high OD ratios were either younger badgers or reproductive females, for which lower body condition typically presented less of a mortality risk in previous analyses of this population. Conclusions Within a single population under the same environmental conditions, we found wide inter-individual variation in both mechanical and total energy expenditure. The adoption of different tactics aligns with relationships between life-history parameters and mortality risk previously studied within the population. Crucially, younger badgers and reproductive females appeared able to tolerate energy expenditure tactics that depleted their body condition more than other badgers. These findings provide a mechanism by which differences in individual energetic context set by life history can maintain heterogeneity in wild populations, providing a wide range of potential energetic tactics under changing environmental conditions.

Abstract Maternal overnutrition during lactation predisposes offspring to develop metabolic diseases and exacerbates the relevant syndromes in males more than females in later life. The hypothalamus is a heterogenous brain region that regulates energy balance. Here we combined metabolic trait quantification of mother and offspring mice under low and high fat diet (HFD) feeding during lactation, with single nucleus transcriptomic profiling of their offspring hypothalamus at peak lacation to understand the cellular and molecular alterations in response to maternal dietary pertubation. We found significant expansion in neuronal subpopulations including histaminergic (Hdc), arginine vasopressin/retinoic acid receptor-related orphan receptor β (Avp/Rorb) and agouti-related peptide/neuropeptide Y (AgRP/Npy) in male offspring when their mothers were fed HFD, and increased Npy-astrocyte interactions in offspring responding to maternal overnutrition. Our study provides a comprehensive offspring hypothalamus map at the peak lactation and reveals how the cellular subpopulations respond to maternal dietary fat in a sex-specific manner during development.

Summary: This study characterized the effect of calorie restriction (CR) on elemental content and stable isotope ratio measurements of bone “collagen” and hair keratin. Adult mice on graded CR (10–40%; 84 days) showed decreased hair δ15N, δ13C, and δ34S values (significantly for δ15N) with increasing CR, alongside a significant increase in bone “collagen” δ15N values and a decrease in “collagen” δ13C values. We propose this was likely due to the intensified mobilization of endogenous proteins, as well as lipids in newly synthesized “collagen”. Elemental analysis of bone “collagen” revealed decreased carbon, nitrogen, and sulfur % content with increasing CR which is attributed to a change in the in vivo bone “collagen” structure with extent of CR. This complexity challenges the use of elemental indicators in the assessment of collagen quality in archaeological studies where nutritional stress may be a factor.

Flexitarianism was one of the top food trends of the summer in 2020. Characterizing reductions in meat eating as representative of the reflections on personal and societal health that were taking place at the time, Canada’s largest food retailer, Loblaw situated the company’s expanded plant-based offerings as a response to a “new us” that was emerging from the COVID-19 pandemic. This article explores the protein pathways that Loblaw opens and closes by promoting “flexitarian choices for our changing lifestyles”. Focussing on reduced beef consumption as a target of flexitarian intervention, I situate flexitarianism in relation to calls for a “protein transition”, which would address the risks the dominant beef industry poses to animal, human, and planetary wellbeing. Drawing from a larger case study on beef shopping at Loblaw supermarkets, I consider the extent to which the version of flexitarianism on display at Loblaw supermarkets might support the status quo in the dominant beef industry. As a flexible framework, flexitarianism holds potential to respond contextually to the needs of varying food networks in Canada. As a defined consumer demographic, however, flexitarianism is poised to reroute this flexibility away from diverse food systems toward adaptable investments, which would insulate financial portfolios from the risks of intensive animal agriculture without requiring meaningful changes within those industries.

IntroductionHuman-induced environmental change is driving a global redistribution of biodiversity, resulting in shifting prey and predation landscapes. These shifting landscapes can lead to changes in behavior, health, and vital rates, with potential implications for population dynamics.MethodsIn the present study, a state-dependent life-history theory model was developed to investigate the individual- and population-level responses of Australian fur seals (Arctocephalus pusillus doriferus) to changes in prey availability and at-sea mortality risk.ResultsRates of pregnancy, pup nursing, and abortion were unaffected by prey availability in the simulated population. Likewise, on-land and at-sea durations were largely unaffected by prey availability, with more pronounced affects for nonreproductive and pregnant females than for lactating females. There was a strong influence of prey availability on the proportion of females that were concurrently pregnant and lactating, largely due to an increase in pup abandonments under low prey availability scenarios. This effect on pup abandonments also had flow on effects for pup recruitment. Increasing at-sea mortality risk resulted in greater offspring losses due to maternal death. The combined impact of prey availability and at-sea mortality risk on the number of simulated female offspring reaching sexual maturity was substantial.DiscussionConsequently, our results suggest high vulnerability of the Australian fur seal population to shifting prey and predation landscapes. These results indicate a need for continued monitoring of Australian fur seal pup production and population dynamics in the face of rapid environmental change.

In the commercial dairy industry worldwide, it is common practice to periodically regroup cows as part of their management strategy within housed systems. While this animal husbandry practice is intended to improve management efficiency, cows may experience social stress as a result of the social environment changes, which may have an impact on their behavioural patterns, performance, and welfare. We investigated whether regrouping altered dairy cows’ behaviour and impacted their cortisol concentration (a physiological marker of stress), oxytocin, milk yield, and quality in a robotic milking system. Fifty-two lactating cows (17 primiparous; 35 multiparous) were moved in groups of 3–5 individuals into established pens of approximately 100 cows. Behaviour of the regrouped cows was directly observed continuously for 4 h/day across 4-time blocks (day-prior (d-1), day-of regrouping (d0), day-after (d + 1), and 6-days after (d + 6) regrouping). Cows were categorised as being with others, alone, or feeding every 2.5 min prior to the assessment of behavioural dynamics. Milk yield (MY) and composition, total daily activity, and rumination time (RUM) data were extracted from the Lely T4C management program (Lely Industries, Maassluis, the Netherlands), and milk samples were collected for cortisol and oxytocin concentration analyses; data were analysed using linear mixed-effect modelling. Primiparous cows were less likely to be interacting with others on d + 1 than d-1 compared with multiparous. However, average bout duration (minutes) between being alone and feeding activity states were similar on d-1, d + 1, and d + 6, for both primiparous and multiparous cows. A reduction in the average alone and feeding bout duration was observed on d0. Multiparous cows spent significantly more total time being alone on d0 compared to d-1. Neither regrouping nor parity statistically influenced milk DM content, energy, or cortisol concentration. Primiparous cows produced 3.80 ± 2.42 kg (12.2%) less MY on d + 1 compared to their d-1, whereas multiparous cows did not change MY. A significant decrease of 0.2% fat was found in both parity groups following regrouping and remained low up to d + 6. Daily activity in both parity groups increased significantly and RUM reduced after regrouping. A significant decrease in oxytocin concentration was observed in all cows on d + 1. The results, specifically for primiparous cows, indicated a negative impact of regrouping on social interactions, due to changes in the social environment which may lead to short-term social instability. Multiparous cows may benefit from previous regrouping experiences.

To establish the criterion‐assessed energy and fluid requirements of female netball players, 13 adult players from a senior Netball Super League squad were assessed over 14 days in a cross‐sectional design, representing a two‐ and one‐match microcycle, respectively. Total energy expenditure (TEE) and water turnover (WT) were measured by doubly labeled water. Resting and activity energy expenditure were measured by indirect calorimetry and Actiheart, respectively. Mean 14‐day TEE was 13.46 ± 1.20 MJ day−1 (95% CI, 12.63–14.39 MJ day−1). Resting energy expenditure was 6.53 ± 0.60 MJ day−1 (95% CI, 6.17–6.89 MJ day−1). Physical activity level was 2.07 ± 0.19 arbitrary units (AU) (95% CI, 1.95–2.18 AU). Mean WT was 4.1 ± 0.9 L day−1 (95% CI, 3.6–4.7 L day−1). Match days led to significantly greater TEE than training (+2.85 ± 0.70 MJ day−1; 95% CI, +1.00– +4.70 MJ day−1; p = 0.002) and rest (+4.85 ± 0.70 MJ day−1; 95% CI, +3.13–+6.56 MJ day−1; p < 0.001) days. Matches led to significantly greater energy expenditure (+1.85 ± 1.27 MJ; 95% CI, +0.95–+2.76 MJ day−1; p = 0.001) than court‐based training sessions. There was no significant difference in TEE (+0.03 ± 0.35 MJ day−1; 95% CI, −0.74–+0.80 MJ day−1; p = 0.936) across weeks. Calibrated Actiheart 5 monitors underestimated TEE (−1.92 ± 1.21 MJ day−1). Energy and fluid turnover were greatest on match days, followed by training and rest days, with no difference across weeks. This study provides criterion‐assessed energy and fluid requirements to inform dietary guidance for female netball players. Highlights: The energy and fluid requirements of female netball players were greatest on match days, followed by training and rest days, with no difference across a one‐ or two‐match weekly microcycle. Therefore, players are encouraged to periodise their intake on a daily basis, aligning with the demands of their training and match schedule.Female netball players have in‐season energy requirements representative of a vigorously active lifestyle (physical activity level: >2.0 arbitrary units). Water turnover varied widely amongst participants (range: 62 mL fat‐free mass [FFM] day−1), while total energy requirements were more homogenous (range: 0.05 MJ FFM day−1).Calibrated Actiheart 5 monitors underestimated female netball player total energy expenditure in comparison to the doubly labelled water criterion (range: −0.38–3.84 MJ day−1). Further research is now required to investigate the validity of Actiheart for measuring team sport athlete energy expenditure. [ABSTRACT FROM AUTHOR]

Variations in physical activity energy expenditure can make accurate prediction of total energy expenditure (TEE) challenging. The purpose of the present study was to determine the accuracy of available equations to predict TEE in individuals varying in physical activity (PA) levels. TEE was measured by DLW in 56 adults varying in PA levels which were monitored by accelerometry. Ten different models were used to predict TEE and their accuracy and precision were evaluated, considering the effect of sex and PA. The models generally underestimated the TEE in this population. An equation published by Plucker was the most accurate in predicting the TEE in our entire sample. The Pontzer and Vinken models were the most accurate for those with lower PA levels. Despite the levels of accuracy of some equations, there were sizable errors (low precision) at an individual level. Future studies are needed to develop and validate these equations. [ABSTRACT FROM AUTHOR]

Two well-known facets in protein synthesis in eukaryotic cells are transcription of DNA to pre-RNA in the nucleus and the translation of messenger-RNA (mRNA) to proteins in the cytoplasm. A critical intermediate step is the removal of segments (introns) containing ∼ 97 % of the nucleic-acid sites in pre-RNA and sequential alignment of the retained segments (exons) to form mRNA through a process referred to as splicing. Alternative forms of splicing enrich the proteome while abnormal splicing can enhance the likelihood of a cell developing cancer or other diseases. Mechanisms for splicing and origins of splicing errors are only partially deciphered. Our goal is to determine if rules on splicing can be inferred from data analytics on nucleic-acid sequences. Toward that end, we represent a nucleic-acid site as a point in a plane defined in terms of the anterior and posterior sub-sequences of the site. The "point-set" representation expands analytical approaches, including the use of statistical tools, to characterize genome sequences. It is found that point-sets for exons and introns are visually different, and that the differences can be quantified using a family of generalized moments. We design a machine-learning algorithm that can recognize individual exons or introns with 91 % accuracy. Point-set distributions and generalized moments are found to differ between organisms. [ABSTRACT FROM AUTHOR]

The assessment of total energy expenditure (TEE) is imperative to ensure appropriate fuelling during competition and training, although the current lack of TEE research in para sport make the prescription of nutritional strategies challenging. This study aimed to assess TEE of an elite wheelchair tennis (WT) player during training and competition of the highest level. One male WT player (age 23.6 years; career high World No. 1; body mass 65.7 kg; VO2max, 45.3 ml.kg−1.min−1) participated. Prior to the assessment, VO2max and maximum heart rate, resting metabolic rate, 10 m sprint speed and upper body skinfold measurements were made. Doubly labelled water assessed TEE during a 19-day period which included the Wimbledon Championships (5 days-3 matches), training (8 days) and the British Open (BO) (6 days-7 matches). Throughout data collection, the participant continued their usual training and preparation. During Wimbledon, TEE was 3118 kcal·d−1: 60.3 kcal·kg−1 FFM: PAL 2.0 and during BO was 3368 kcal·day−1: 65.1 kcal·kg−1 FFM: PAL 2.2. Mean daily activity was 124 mins and 132 mins, respectively. During training, TEE was 3177kcal·day-1: 61.4kcal·kg-1 FFM: PAL 2.0: mean daily activity was 138 mins. These findings show the TEE of an elite WT player captured during a period of training and high-level competition, alongside data outlining the physiological profile of a world-class para-athlete. [ABSTRACT FROM AUTHOR]

Objectives: Using equations to predict resting metabolic rate (RMR) has yielded different degrees of validity, particularly when sex and different physical activity levels were considered. Therefore, the purpose of the present study was to determine the validity of several different predictive equations to estimate RMR in female and male adults with varying physical activity levels. Method: We measured the RMR of 50 adults (26 females and 24 males) evenly distributed through activity levels varying from sedentary to ultra‐endurance. Body composition was measured by dual X–ray absorptiometry and physical activity was monitored by accelerometry. Ten equations to predict RMR were applied (using Body Mass [BM]: Harris & Benedict, 1919; Mifflin et al., 1990 [MifflinBM]; Pontzer et al., 2021 [PontzerBM]; Schofield, 1985; FAO/WHO/UNU, 2004; and using Fat‐Free Mass (FFM): Cunningham, 1991; Johnstone et al., 2006; Mifflin et al., 1990 [MifflinFFM]; Nelson et al. 1992; Pontzer et al., 2021 [PontzerFFM]). The accuracy of these equations was analyzed, and the effect of sex and physical activity was evaluated using different accuracy metrics. Results: Equations using BM were less accurate for females, and their accuracy was influenced by physical activity and body composition. FFM equations were slightly less accurate for males but there was no obvious effect of physical activity or other sample parameters. PontzerFFM provides higher accuracy than other models independent of the magnitude of RMR, sex, activity levels, and sample characteristics. Conclusion: Equations using FFM were more accurate than BM equations in our sample. Future studies are needed to test the accuracy of RMR prediction equations in diverse samples. [ABSTRACT FROM AUTHOR]

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This document is a response to comments made by Ludwig et al. on a previous paper. The authors clarify that their study did not aim to test the carbohydrate insulin model (CIM), but rather focused on the impact of high levels of dietary fat. They also address criticisms regarding the measurement of body composition changes and the use of saturated fat and high-glycemic load carbohydrates in their study. The authors conclude that none of the models they tested provided an exact description of what happened, and express openness to the possibility that the hedonic overdrive model may be incorrect. [Extracted from the article]