Extreme events reveal an alimentary limit on sustained maximal human energy expenditure

Thurber, Caitlin; Dugas, Lara R.; Ocobock, Cara; Carlson, Bryce A.; Speakman, John R.; Pontzer, Herman

doi:10.1126/sciadv.aaw0341

Cited by 100 publications

(126 citation statements)

References 45 publications

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“…Consistent with these reports, recent analysis of energy expenditure during pregnancy (Dunsworth, Warrener, Deacon, Ellison, & Pontzer, ) and by athletes participating in contests ranging from half‐day triathlons to multimonth ultra‐endurance runs revealed an ultimate limit of sustainable energy expenditure (Thurber et al, ). Thurber and colleagues found that over time the maximal daily energy output decreases curvilinearly to a value below three times basal metabolic rate.…”

Section: Evolved Constraints Of Energy Expenditurementioning

confidence: 59%

Human athletic paleobiology; using sport as a model to investigate human evolutionary adaptation

Longman

Wells²,

Stock

2020

American J Phys Anthropol

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The use of sport as a conceptual framework offers unprecedented opportunities to improve our understanding of what the body does, shedding new light on our evolutionary trajectory, our capacity for adaptation, and the underlying biological mechanisms. This approach has gained traction over recent years. To date, sport has facilitated exploration not only of the evolutionary history of our species as a whole, but also of human variation and adaptation at the interindividual and intraindividual levels. At the species level, analysis of lower and upper limb biomechanics and energetics with respect to walking, running and throwing have led to significant advances in the understanding of human adaptations relative to other hominins. From an interindividual perspective, investigation of physical activity patterns and endurance running performance is affording greater understanding of evolved constraints of energy expenditure, thermoregulatory energetics, signaling theory, and morphological variation. Furthermore, ultra-endurance challenges provoke functional trade-offs, allowing new ground to be broken in the study of life history trade-offs and human adaptability. Human athletic paleobiology-the recruitment of athletes as study participants and the use of contemporary sports as a model for studying evolutionary theory-has great potential. Here, we draw from examples in the literature to provide a review of how the use of athletes as a model system is enhancing understanding of human evolutionary adaptation. K E Y W O R D S adaptation, human athletic paleobiology, human evolution, plasticity, sport 1 | INTRODUCTION The fossil record provides evidence about the form and physical characteristics of the human or hominin body, and their changes over time. However, a central challenge of hominin paleobiology is the interpretation of the body's function from its form; how do we walk, run, use tools, and move within the landscape, and how did these functions themselves evolve? Stemming from this, what is the nature of the physiological mechanisms that underpin observed variation in form and function? The use of sport as a conceptual framework offers unprecedented opportunities to improve our understanding of what the body does, shedding new light on our evolutionary trajectory, our capacity for adaptation, and the underlying biological mechanisms.There has been increasing interest in the model system provided by athletes to enhance our understanding of human evolutionary theory. To date, studies of athletes have facilitated exploration of three key levels of variation and adaptation within the field of human evolution ( Figure 1).

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Section: Evolved Constraints Of Energy Expenditurementioning

confidence: 59%

Human athletic paleobiology; using sport as a model to investigate human evolutionary adaptation

Longman

Wells²,

Stock

2020

American J Phys Anthropol

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“…Human endosomatic needs due to nourishment have been estimated in c. 10 (MJ edible /(p•d)), but recent studies suggest they can reach up to 25 [13], which roughly corresponds to an interval 0.087-0.217 (toe/(p•y)) and depends on individual physical activities and metabolism. In this respect, Sanfilippo et al [14] studied the energy requirements and the environmental impact of different dietary choices and concluded that beef-based meals present a cumulative energy demand (CED) footprint which is 6.25 times the edible energy in foods, while the vegetarian menu merely requires 3.28 and the poultry and pork choices demand intermediate values between 3.50-4.50.…”

Section: Introductionmentioning

confidence: 99%

Energy Sustainability Analysis (ESA) of Energy-Producing Processes: A Case Study on Distributed H2 Production

Gómez-Camacho

Ruggeri

2019

Sustainability

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In the sustainability context, the performance of energy-producing technologies, using different energy sources, needs to be scored and compared. The selective criterion of a higher level of useful energy to feed an ever-increasing demand of energy to satisfy a wide range of endo- and exosomatic human needs seems adequate. In fact, surplus energy is able to cover energy services only after compensating for the energy expenses incurred to build and to run the technology itself. This paper proposes an energy sustainability analysis (ESA) methodology based on the internal and external energy use of a given technology, considering the entire energy trajectory from energy sources to useful energy. ESA analysis is conducted at two levels: (i) short-term, by the use of the energy sustainability index (ESI), which is the first step to establish whether the energy produced is able to cover the direct energy expenses needed to run the technology and (ii) long-term, by which all the indirect energy-quotas are considered, i.e., all the additional energy requirements of the technology, including the energy amortization quota necessary for the replacement of the technology at the end of its operative life. The long-term level of analysis is conducted by the evaluation of two indicators: the energy return per unit of energy invested (EROI) over the operative life and the energy payback-time (EPT), as the minimum lapse at which all energy expenditures for the production of materials and their construction can be repaid to society. The ESA methodology has been applied to the case study of H2 production at small-scale (10–15 kWH2) comparing three different technologies: (i) steam-methane reforming (SMR), (ii) solar-powered water electrolysis (SPWE), and (iii) two-stage anaerobic digestion (TSAD) in order to score the technologies from an energy sustainability perspective.

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“…Experimental models that test the limits of human function have been instrumental in characterising the capacity and regulation of numerous physiological systems, including the capacity for maximal O 2 uptake (1) , time spent without energy intake (2) and most recently maximal levels of sustained energy expenditure (3) . This approach advances our fundamental understanding of human physiology and provides important insights into susceptibility towards pathophysiology.…”

mentioning

confidence: 99%

Physiological responses to maximal eating in men

et al. 2020

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This study investigated metabolic, endocrine, appetite and mood responses to a maximal eating occasion in fourteen men (mean: age 28 (sd 5) years, body mass 77·2 (sd 6·6) kg and BMI 24·2 (sd 2·2) kg/m2) who completed two trials in a randomised crossover design. On each occasion, participants ate a homogenous mixed-macronutrient meal (pizza). On one occasion, they ate until ‘comfortably full’ (ad libitum) and on the other, until they ‘could not eat another bite’ (maximal). Mean energy intake was double in the maximal (13 024 (95 % CI 10 964, 15 084) kJ; 3113 (95 % CI 2620, 3605) kcal) compared with the ad libitum trial (6627 (95 % CI 5708, 7547) kJ; 1584 (95 % CI 1364, 1804) kcal). Serum insulin incremental AUC (iAUC) increased approximately 1·5-fold in the maximal compared with ad libitum trial (mean: ad libitum 43·8 (95 % CI 28·3, 59·3) nmol/l × 240 min and maximal 67·7 (95 % CI 47·0, 88·5) nmol/l × 240 min, P < 0·01), but glucose iAUC did not differ between trials (ad libitum 94·3 (95 % CI 30·3, 158·2) mmol/l × 240 min and maximal 126·5 (95 % CI 76·9, 176·0) mmol/l × 240 min, P = 0·19). TAG iAUC was approximately 1·5-fold greater in the maximal v. ad libitum trial (ad libitum 98·6 (95 % CI 69·9, 127·2) mmol/l × 240 min and maximal 146·4 (95 % CI 88·6, 204·1) mmol/l × 240 min, P < 0·01). Total glucagon-like peptide-1, glucose-dependent insulinotropic peptide and peptide tyrosine–tyrosine iAUC were greater in the maximal compared with ad libitum trial (P < 0·05). Total ghrelin concentrations decreased to a similar extent, but AUC was slightly lower in the maximal v. ad libitum trial (P = 0·02). There were marked differences on appetite and mood between trials, most notably maximal eating caused a prolonged increase in lethargy. Healthy men have the capacity to eat twice the energy content required to achieve comfortable fullness at a single meal. Postprandial glycaemia is well regulated following initial overeating, with elevated postprandial insulinaemia probably contributing.

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Extreme events reveal an alimentary limit on sustained maximal human energy expenditure

Cited by 100 publications

References 45 publications

Human athletic paleobiology; using sport as a model to investigate human evolutionary adaptation

Human athletic paleobiology; using sport as a model to investigate human evolutionary adaptation

Energy Sustainability Analysis (ESA) of Energy-Producing Processes: A Case Study on Distributed H2 Production

Physiological responses to maximal eating in men

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