Abstract:Life involves a continuous use of energy, but food intake, which supplies that energy, is episodic. Feeding is switched on and off by a complex array of predominantly gut-derived peptides (and potentially nutrients) that initiate and terminate feeding bouts. Energy is stored as glucose and glycogen to overcome the problem of the episodic nature of intake compared with the continuous demand. Intake is also adjusted to meet immediate changes in demands. Most animals also store energy as fat. In some cases, this … Show more
“…Third, advantageous host-related factors may favor overweight compared with normal weight patients. In evolutionary terms, excess fat serves the purpose of storing energy in anticipation of known future shortfalls, such as hibernation, migration, or reproduction [20]. In a similar manner, patients with moderate amounts of excess adiposity may better combat the physiological stresses of cancer treatment.…”
Section: The Associations Are True and Plausiblementioning
Body mass index (BMI), as an approximation of general adiposity, is an established risk factor for incidence of several adult cancer types, including colorectal cancer (CRC). There is a common perception that these relationships extrapolate directly as adverse prognostic factors after diagnosis, but evidence for this is lacking. The paper from Sclesinger et al. in this issue of the journal adds a new dimension to this debate focusing on relationships of post-diagnosis BMI (as a marker of the steady-state weight among survivors) and survival, and provides evidence on a decreased mortality risk among overweight (post-diagnosis BMI 25.0-29.9 kg/m(2)) compared with normal weight (post-diagnosis BMI 18.5-24.9 kg/m(2)) CRC survivors-an example of an 'obesity paradox.' The observation of the 'obesity paradox' is well documented in the methodology literature, but perhaps, less familiar to the cancer readership. Three broad classes of explanation are posited: (1) the associations are true and plausible; (2) the associations are false and reflect methodological issues; or (3) the observations represent a specific form of selection bias, known as collider bias. The present author argues that the obesity paradox reflects the latter-a product of a statistical bias-and emphasizes that, while these findings are hypothesis generating, they will not alter clinical practice or recommendations.
“…Third, advantageous host-related factors may favor overweight compared with normal weight patients. In evolutionary terms, excess fat serves the purpose of storing energy in anticipation of known future shortfalls, such as hibernation, migration, or reproduction [20]. In a similar manner, patients with moderate amounts of excess adiposity may better combat the physiological stresses of cancer treatment.…”
Section: The Associations Are True and Plausiblementioning
Body mass index (BMI), as an approximation of general adiposity, is an established risk factor for incidence of several adult cancer types, including colorectal cancer (CRC). There is a common perception that these relationships extrapolate directly as adverse prognostic factors after diagnosis, but evidence for this is lacking. The paper from Sclesinger et al. in this issue of the journal adds a new dimension to this debate focusing on relationships of post-diagnosis BMI (as a marker of the steady-state weight among survivors) and survival, and provides evidence on a decreased mortality risk among overweight (post-diagnosis BMI 25.0-29.9 kg/m(2)) compared with normal weight (post-diagnosis BMI 18.5-24.9 kg/m(2)) CRC survivors-an example of an 'obesity paradox.' The observation of the 'obesity paradox' is well documented in the methodology literature, but perhaps, less familiar to the cancer readership. Three broad classes of explanation are posited: (1) the associations are true and plausible; (2) the associations are false and reflect methodological issues; or (3) the observations represent a specific form of selection bias, known as collider bias. The present author argues that the obesity paradox reflects the latter-a product of a statistical bias-and emphasizes that, while these findings are hypothesis generating, they will not alter clinical practice or recommendations.
“…Although the hormone leptin, produced primarily in white adipose tissue [7,8] has been often suggested to be the peripheral fat signal in this model, a central location for the 'set point' has never been identified. Moreover, this model is in conflict with observations of the patterns of changes in animal and human body weight [9,10] not least of which is the obesity epidemic itself [2].…”
mentioning
confidence: 89%
“…Resting metabolic rate was estimated as the average value of the five lowest consecutive readings (equivalent to 2 min and 30 s in the chamber) [24], and the average of the measurements made on consecutive days was used for further analysis. VO 2 was calculated after Depocas and Hart [25] as VO 2 …”
“…Any sustained imbalance between energy intake and expenditure will result either in loss of weight (Jequier and Tappy, 1999;Schwartz, 2012;Speakman, 2014), or attainment of a positive energy balance, ultimately leading to weight gain and obesity. Previous work has often involved controlled, laboratory-based protocols to manipulate and examine acute food intake responses to physical activity (Bozinovski et al, 2008;Dodd, Welsman, and Armstrong, 2008).…”
. (2018) 'Food intake and appetite following school-based high-intensity interval training in 911-year-old children.', Journal of sports sciences., 36 (3). pp. 286-292. Further information on publisher's website:
Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. caroline.dodd-reynolds@durham.ac.uk
ACKNOWLEDGEMENTS:The authors thank the school, the children and their parents, the head teacher and the cook for their participation in this study.
1
ABSTRACTUsing a randomised cross-over design, free-living lunch intake and subjective appetite were examined in 10 children (9.8±0.6 years) following high intensity interval training (HIIT) versus a control sedentary (SED) period, within a school setting. The 22 minute HIIT took place during a regular PE lesson and consisted of two rounds of 4 x 30 second sprints. Foods were offered at a regular school lunch immediately following HIIT and SED and were matched between conditions. All food was covertly weighed before and after the meal. Hunger, fullness and prospective consumption were reported immediately before and after HIIT/SED, using visual analogue scales. Heart rate was higher during HIIT than SED
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