Metabolic fuels and reproduction in female mammals

Wade, George N.; Schneider, Jill E.

doi:10.1016/s0149-7634(05)80183-6

Cited by 617 publications

(361 citation statements)

References 410 publications

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“…These stores most commonly take the form of adipose tissue; 11 however, some small species, such as hamsters, also use extra-corporeal food hoards. 12 Again, small mammals may require fat simply to accommodate diurnal variability in energy availability. Lactating mice lay down fat in the night to fund lactation in the day.…”

Section: What Is Thrift?mentioning

confidence: 99%

Thrift: a guide to thrifty genes, thrifty phenotypes and thrifty norms

Wells¹

2009

Int J Obes

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There is a growing interest in evolutionary models of human adiposity. Frequent reference has been made to 'thrifty genes' or 'thrifty phenotypes', referring to a variety of metabolic or behavioural traits that in one or the other way imply frugality in the expenditure or storage of energy. However, there is confusion over how the strategy of thrift has been incorporated into human biology. At the broadest level, humans represent a thrifty species relative to other mammals, indicating that metabolic adaptations had a crucial role in the emergence of the Homo lineage, in particular in buffering reproduction from ecological stochasticity. In contemporary humans, some variability in adiposity may be attributable to genotypes systematically favoured in certain ecological settings. Genetic variability is also present within populations, and may be considered bet hedging (distributing risk across offspring to increase parental fitness). Bet hedging is an alternative to genetic drift for accounting for genetic variability in the absence of strong selective pressures. Contrasting with genetic variability emerging over the long-term, thrifty phenotypes represent a response to short-term ecological variability. Physiological plasticity allows the emergence of variability across the life course in response to ecological cues experienced directly or by very recent ancestors. Finally, cultural norms or individual preferences allow voluntary behavioural manipulation of thrift in individuals. Overall, there is a range of factors and processes both favouring and opposing thrifty genes, which may reflect moderate bet hedging rather than systematic adaptation. Plasticity protects the genome from selective pressures by tailoring the organism to ongoing ecological conditions. The fact that obesity can occur in different individuals through different genotypes, life histories and behaviours indicates that different treatments are also likely to be required.

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Section: What Is Thrift?mentioning

confidence: 99%

Thrift: a guide to thrifty genes, thrifty phenotypes and thrifty norms

Wells¹

2009

Int J Obes

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“…[24][25][26][27][28][29][30] Consequently, it has been hypothesized that estrogens reduce appetite and EI and are thus reciprocal to a possible appetite-stimulating effect of progesterone in animals. In humans, a review has summarized EI in relation to menstrual cycle phases in 30 studies, which included a total of 37 groups of women.…”

Section: Energy Intakementioning

confidence: 99%

“…26 This suggests that the observations listed above may be due to an inverse, noncausal association between the plasma concentration of estrogens and EI, rather than due to an appetite-stimulating effect of progesterone. 24,30,48 In this context estradiol is thought to be the crucial inhibitory signal linking the HPG axis to the neural control of feeding, and thereby inhibiting EI by reducing the amount of food consumed at a single meal. 49 Ovariectomy on rats, which disrupts the normal HPG function by preventing the secretion of estrogens and nearly eliminating all estradiol from the circulation, has been shown to increase EI, resulting in a 10-30% increase in body fat.…”

Section: Energy Intakementioning

confidence: 99%

Impact of the menstrual cycle on determinants of energy balance: a putative role in weight loss attempts

2007

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Women's weight and body composition is significantly influenced by the female sex-steroid hormones. Levels of these hormones fluctuate in a defined manner throughout the menstrual cycle and interact to modulate energy homeostasis. This paper reviews the scientific literature on the relationship between hormonal changes across the menstrual cycle and components of energy balance, with the aim of clarifying whether this influences weight loss in women. In the luteal phase of the menstrual cycle it appears that women's energy intake and energy expenditure are increased and they experience more frequent cravings for foods, particularly those high in carbohydrate and fat, than during the follicular phase. This suggests that the potential of the underlying physiology related to each phase of the menstrual cycle may be worth considering as an element in strategies to optimize weight loss. Studies are needed to assess the weight loss outcome of tailoring dietary recommendations and the degree of energy restriction to each menstrual phase throughout a weight management program, taking these preliminary findings into account.

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“…Despite the pathological connotations, it is likely that conditions of sub‐optimal nutrition will be encountered at some point during the lifetime of a mammal, and animals will have been selected to protect functions necessary for survival at the expense of less essential processes. Thus, available energy is partitioned according to a set of priorities that maximize the chance of survival and thereby optimize long term reproductive success (Wade, 1992). …”

Section: Introductionmentioning

confidence: 99%

Short‐term resource allocation during extensive athletic competition

Longman

Prall

Shattuck

et al. 2017

American J Hum Biol

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ObjectivesFollowing predictions from life history theory, we sought to identify acute trade‐offs between reproductive effort (as measured by psychological arousal) and somatic maintenance (via functional measures of innate immunity) during conditions of severe energetic imbalance.MethodsSixty‐six male ultramarathon runners (ages 20 to 37 years) were sampled before and after a lengthy race. Saliva and sera were collected for testosterone and immunological analyses (hemolytic complement activity and bacterial killing ability). Lean body mass was assessed by bioelectrical impedance, and libido was measured using a slideshow of arousing and neutral images.ResultsFollowing predictions, there was a significant decrease in salivary testosterone levels (109.59 pg/mL versus 97.61 pg/mL, P < .001) and arousal scores in response to provocative images (5.40 versus 4.89, P = .001) between prerace and postrace time points. Additionally, participant bacterial killing ability (P = .035) and hemolytic complement activity (P = .021) increased between prerace and postrace.ConclusionsDecreased libido and testosterone with concomitant heightened innate immune responses suggest a shift in energetic priorities away from reproduction and toward maintenance/defense during a period of energetic stress.

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Metabolic fuels and reproduction in female mammals

Cited by 617 publications

References 410 publications

Thrift: a guide to thrifty genes, thrifty phenotypes and thrifty norms

Thrift: a guide to thrifty genes, thrifty phenotypes and thrifty norms

Impact of the menstrual cycle on determinants of energy balance: a putative role in weight loss attempts

Short‐term resource allocation during extensive athletic competition

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