High protein diet maintains glucose production during exercise-induced energy deficit: a controlled trial

<p>Abstract</p> <p>Background</p> <p>Inadequate energy intake induces changes in endogenous glucose production (GP) to preserve muscle mass. Whether addition provision of dietary protein modulates GP response to energy deficit is unclear. The objective was to determine whether exercise-induced energy deficit effects on glucose metabolism are mitigated by increased dietary protein.</p> <p>Methods</p> <p>Nineteen men ([mean ± SD] 23 ± 2 y, VO_2peak59 ± 5 ml·kg^-1·min^-1) were divided into three groups, two consuming moderate (MP; 0.9 g protein kg^-1d^-1), and one high (HP; 1.8 g protein kg^-1d^-1) protein diets (55% energy from carbohydrate) for 11 days. Following 4 days of energy balance (D1-4), energy expenditure was increased for 7 days (D5-12) in all groups. Energy intake was unchanged in two, creating a 1000 kcal d^-1deficit (DEF-MP, DEF-HP; n = 6, both groups), whereas energy balance was maintained in the third (BAL-MP, n = 7). Biochemical markers of substrate metabolism were measured during fasting rest on D4 and D12, as were GP and contribution of gluconeogenesis to endogenous glucose production (<it>f</it>_gng) using 4-h primed, continuous infusions of [6,6-²H₂]glucose (dilution-method) and [2-¹³C]glycerol (MIDA technique). Glycogen breakdown (GB) was derived from GP and <it>f</it>_gng.</p> <p>Results</p> <p>Plasma β-hydroxybutyrate levels increased, and plasma glucose and insulin declined from D4 to D12, regardless of group. DEF-MP experienced decreased plasma GP from D4 to D12 ([mean change ± SD] 0.24 ± 0.24 mg·kg^-1·min^-1), due to reduced GB from D4 (1.40 ± 0.28 mg·kg^-1·min^-1) to D12 (1.16 ± 0.17 mg·kg^-1·min^-1), P < 0.05. Conversely, BAL-MP and DEF-HP sustained GP from D4 to D12 ([mean change ± SD] 0.1 ± 0.5 and 0.0 ± 0.2 mg·kg^-1·min^-1, respectively) by maintaining GB.</p> <p>Conclusion</p> <p>Exercise-induced energy deficit decreased GP and additional dietary protein mitigated that effect.</p

Statement of the Third International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015

The third International Exercise-Associated Hyponatremia (EAH) Consensus Development Conference convened in Carlsbad, California in February 2015 with a panel of 17 international experts. The delegates represented 4 countries and 9 medical and scientific sub-specialties pertaining to athletic training, exercise physiology, sports medicine, water/sodium metabolism, and body fluid homeostasis. The primary goal of the panel was to review the existing data on EAH and update the 2008 Consensus Statement.1 This document serves to replace the second International EAH Consensus Development Conference Statement and launch an educational campaign designed to address the morbidity and mortality associated with a preventable and treatable fluid imbalance. The following statement is a summary of the data synthesized by the 2015 EAH Consensus Panel and represents an evolution of the most current knowledge on EAH. This document will summarize the most current information on the prevalence, etiology, diagnosis, treatment and prevention of EAH for medical personnel, athletes, athletic trainers, and the greater public. The EAH Consensus Panel strove to clearly articulate what we agreed upon, did not agree upon, and did not know, including minority viewpoints that were supported by clinical experience and experimental data. Further updates will be necessary to both: (1) remain current with our understanding and (2) critically assess the effectiveness of our present recommendations. Suggestions for future research and educational strategies to reduce the incidence and prevalence of EAH are provided at the end of the document as well as areas of controversy that remain in this topic. [excerpt

Diet and Physical Performance

This paper provides a historical summary of military nutrition research into the role of diet for sustaining soldier physical performance. Studies of underfeeding document that physical performance is preserved during several days of underfeeding provided sufficient carbohydrate and minerals are consumed to minimize the diuresis associated with semi-starvation diets and serial intake of carbohydrate is available to support metabolism during prolonged work. The Military Recommended Dietary Allowances, AR 40-25, currently recommends that when restricted rations are required, that the ration contain at least 1100–1500 kcal, 50–70 g of protein, and a minimum of 100 g of carbohydrate on a daily basis. This low energy diet, however, is not recommended for subsistence for longer than 10 consecutive days. Dietary carbohydrate intakes of approximately 300–400 g will more closely match the quantity of carbohydrate oxidized to meet daily energy requirements during field operations. Research into the potential advantages of dietary supplements has generally not proved advantageous when compared to eating a well balanced diet. Future investigations of the role of diet for sustaining soldier health and performance should be directed toward a better understanding of the influence of energy intake and macro-nutrient composition for preserving lean body mass, reducing susceptibility to illness and injury and enhancing recovery during and after sustained operations

The day-to-day variability of oxygen uptake during submaximal arm ergometry

Ball State University LibrariesLibrary services and resources for knowledge buildingMasters ThesesThere is no abstract available for this thesis.Thesis (M.S.)--Ball State University, 1984

Eating rate during a fixed-portion meal does not affect postprandial appetite and gut peptides or energy intake during a subsequent meal

Eating rate has recently been shown to influence energy intake and appetite during an ad libitummeal, and alter postprandial secretion of glucagon-like peptide-1 (GLP-1) and peptide-YY (PYY) following a fixed-portionmeal. Whether these effects influence satiety, as measured by energy intake at the subsequent meal, is unclear. We manipulated eating rate during a fixed-portion meal in order to examine how eating behavior and associated periprandial and postprandial responses of putative endocrine mediators of appetite would affect energy intake at the following meal in fifteen non-obese (BMI ≥ 25 kg/m²) and ten obese (BMI ≥ 30 kg/m²) healthy adult men and women. In randomorder, each participant consumed a standardized, fixed-portion meal in 7 (FM), 14 (MM) or 28 (SM) minutes. Fullness, measured by the Satiety Labeled Intensity Magnitude (SLIM) scale, serum insulin, glucose, leptin, pancreatic polypeptide (PP), PYY,GLP-1, neuropeptide-Y, and plasma cholecystokinin (CCK)were measured for 3 h following the fixed-portion meal. Ad libitumenergy intake at the next meal was then measured. Eating slowly delayed time to peak fullness (P ≤ 0.05), but did not alter peak fullness. Peak PP concentrations were attenuated during FM compared to MM and SM(P ≤ 0.05) and were reached earlier during MM compared to SM (P ≤ 0.05). A meal-by-time interaction (P ≤ 0.05), but no differences in AUC, peak, or time to peak were observed for CCK. No additional between meal differences in AUC, peak or time to peak for any endocrine mediator of appetite was observed. Ad libitum energy intakewas not different between trials. In conclusion, the rate at which a fixed-portion meal is consumed does not appear to alter satiety despite a small effect on PP and CCK responses

Association between stress fracture incidence and predicted body fat in United States Army Basic Combat Training recruits

Abstract Background A stress fracture (SF) is a highly debilitating injury commonly experienced in United States Army Basic Combat Training (BCT). Body fat (BF) may be associated with this injury but previous investigations (in athletes) have largely used SF self-reports and lacked sufficient statistical power. This investigation developed an equation to estimate %BF and used that equation to examine the relationship between %BF and SF risk in BCT recruits. Methods Data for the %BF predictive equation involved 349 recruits with BF obtained from dual-energy X-ray absorptiometry. %BF was estimated using body mass index (BMI, weight/height2), age (yr), and sex in the entire population of BCT recruits over an 11-year period (n = 583,651). Medical information was obtained on these recruits to determine SF occurrence. Recruits were separated into deciles of estimated %BF and the risk of SFs determined in each decile. Results The equation was %BF = − 7.53 + 1.43 ● BMI + 0.13 ● age − 14.73 ● sex, with sex either 1 for men or 0 for women (r = 0.88, standard error of estimate = 4.2%BF). Among the men, SF risk increased at the higher and lower %BF deciles: compared to men in the mean %BF decile, the risk of a SF for men in the first (lowest %BF) and tenth (highest %BF) decile were 1.27 (95%confidence interval (95%CI) = 1.17–1.40) and 1.15 (95%CI = 1.05–1.26) times higher, respectively. Among women, SF risk was only elevated in the first %BF decile with risk 1.20 (95%CI = 1.09–1.32) times higher compared to the mean %BF decile. Conclusions Low %BF was associated with higher SF risk in BCT; higher %BF was associated with higher SF risk among men but not women