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This investigation examined acute energy compensation and macronutrient intake in habitually active and sedentary, college-aged males, following an exercise session as compared to a resting (control) session, to see if habitually active males compensate intake better to an energy deficit incurred by exercise, than sedentary males. Participants were males, aged 18-30 years, of a normal percent body fat and body mass index, and exercised < 60 min per week (sedentary) or > 150 min per week (habitually active). Participants came in for two sessions: 1) 45 minutes of resting (control) and then eating an ad libitum meal; and 2) riding a cycle ergometer for 45 minutes (exercise) and then eating an ad libitum meal. Sessions were counterbalanced across participants. Energy and macronutrient intake were calculated for the meal and over the remaining part of the day. Sedentary individuals ate significantly less during the meal in the exercise session (which expended a mean of 453.5 kcals across both groups) as compared to the control session (934.8 + 222.0 kcals vs. 1073.9 + 470.3 kcals, p < 0.03), which demonstrated negative energy compensation (-30.6%). The habitually active group showed no significant difference in energy intake between sessions at the meal (1016.8 + 396.7 kcal [control] vs. 1105.6 + 389.2 kcal [exercise]). While the habitually active group showed no significant difference in intake at the meal, the slight increase in intake at the meal in the exercise session demonstrated some energy compensation (19.6%), which was significantly better (p < 0.03) than that in the sedentary group. No differences in macronutrient intake at the meal were found between the sessions. Over the day following the sessions, both groups reported a significant increase in energy intake after the exercise session as compared to the control session (1457.5 + 646.2 kcals vs. 1356.1 + 657.2 kcals, p < 0.04), with no difference in macronutrient intake between the sessions. These results indicate that, although complete acute compensation did not occur, the habitually active group acutely compensated intake significantly more so than the sedentary group, demonstrating better energy regulation ability.

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 109-127).

Diss. (sammanfattning) Skara : Sveriges lantbruksuniv., 2009. / Härtill 4 uppsatser.

Osteoporosis literally means 'porous bone" and is characterized by an increase in bone fragility and susceptibility to fracture, which typically involves the wrist, spine and hip (South African Medical Association (SAMA) Working Group, 2000). In South Africa osteoporosis and fractures are more common in whites than in blacks. African-American men experience hip fractures at a rate of only half of that of Caucasian men. The bone mass in Africans were found to be 6 - 12 % higher than in Caucasians at all ages. A higher peak bone density at skeletal maturity in African-Americans were found, so that despite comparable age related bone loss, African Americans reach the fracture threshold less frequently than whites. Age-related bone loss that begins later, is less severe, or occurs in different skeletal sites in African-Americans than whites (Luckey et al., 1996). American whites have a higher bone turnover than American blacks, but in contrast to this American data. South African blacks may have a higher bone turnover and lower bone density than whites (Daniels et a/., 1995). If it is compared with Caucasians a lower rate of hip fracture in South African blacks were found, despite lower bone density at all ages (Villa, 1994). The lower fracture rate in blacks than in whites is because of greater bone mass and higher bone turnover leading to more frequent renewal of damaged bone. Blacks excrete less urinary calcium, and show no skeletal sensitivity towards the parathyroid hormone. Few studies focus on older black South African men and osteoporosis. Objectives The aim of this study was to investigate the relationship of calcium intake, vitamin D status, anthropometry and physical activity and bone density in black South African men. Methods A case-control study design was used, in which variables associated with bone density were compared. The case group were men with fractures of the proximal femur, the proximal humerus or the distal radius and an equal number of age-matched healthy black men (with not more than a 5-year age difference) with no fracture (the proximal femur and humerus and distal radius) previously, was recruited as a control group. Bone density was measured with DEXA. Fat percentage was measured with a Tanita scale. Biochemical analyses were done. Questionnaires were used to gather demographic, activity and dietary information. To our knowledge, this is the first case-control study on osteoporotic fractures in South African black men. Results Both the groups' bone mineral densities were lower than recommended. The bone density of the case group for lumbar and hip regions was 0.86 and 0.88 and the control group's bone density for lumbar region was 0.95 and hip region 0.91. The control group was more physically active and had a better nutritional status than the case group. The control group's calcium intake was higher but the vitamin D status was lower than the case group. Both calcium and vitamin D status were not statistically significant (pc0.5), between the two groups. Body mass indices of the groups were the same. The serum albumin was higher in the control group than in the case group. The case group serum calcium was higher than the control group. Both serum albumin and serum calcium were statistical significant between the two groups. There were no statistically significant differences in any of the other biochemical variables between the two groups. Serum phosphate and serum vitamin D were statistical significant for bone density of the hip and lumbar regions. Conclusion To conclude it seems logical to suggest a healthy diet with optimal macro- and micro nutrient intake. Maintain ideal body weight and body fat percentage and recommend regular but moderate-weight-bearing exercise from a young age throughout adult life, as part of a strategy to prevent and treat osteoporosis. In the present study black South African men present with low bone mineral density, but other studies indicated a lower rate of hip fracture in South African blacks, despite lower bone density at all ages. It can be recommended that other factors may play a role in black South African men with osteoporosis. Factors such as serum phosphorus, 25-hydroxy-vitamin D, body mass index (BMI), physical activity index (PAI), animal protein, total fat intake and dietary calcium are important determinants of BMD in older South African blacks, as shown in the present study. Osteoporosis is a multi factorial problem and must be treated that way. / Thesis (M.Sc. (Dietetics))--North-West University, Potchefstroom Campus, 2004.

Objective. To compare energy balance and nutrient intake of elite and non-elite school-aged gymnasts, as well as to evaluate their nutritional knowledge and eating attitude and its effect on dietary intake and practices. Methods. Demographic information, anthropometric measurements, menstrual status, sources of nutritional information, nutritional habits as well as supplement use was documented. Eating attitudes were measured by the EAT26 test and nutritional knowledge by a standardised questionnaire. Dietary intake and practices were determined with a 3-day weighed food record, while energy expenditure was measured with an Actical® accelerometer (Mini Mitter Co., Inc. Bend, OR, USA). Results. The total daily energy intake (non-elite = 6 944.37 ± 1 272.28 kJ vs. elite = 6 543.01 ± 2 570 kJ) in both groups was similar to their daily energy expenditure values (non-elite = 6 393.77 ± 1 244.19 kJ vs. elite = 6 696.09 ± 1 676.58 kJ). Elite gymnasts tended to have higher protein (21.37 vs. 15.4% total energy intake (TE), small effect size, d = 0.1) and lower fat (28.9 vs. 33.6% TE, medium effect size, d = - 0.6) intakes. More non-elite gymnasts (n = 7, 88.88%) used micronutrient supplements than elite gymnasts (n = 4, 45.45%, medium effect size, d = 0.45). Most of the gymnasts (55%) ate snacks during the day, which consisted mostly of refined carbohydrates. In the total group of gymnasts the most frequently used source of nutritional information was the coach (60%). There was no difference in nutritional knowledge between the groups (elite = 61.8% vs. non-elite = 62.8% respectively). Lastly, elite gymnasts had a practically significantly higher risk than non-elite gymnasts to follow a diet (large effect size, d = 1.32), while non-elite gymnasts exercised practically significantly more self-control over their food intake com pared to elite gymnasts (large effect size, d = - 1.03). Conclusions. South African elite gymnasts do not differ from non-elite gymnasts in terms of energy-, carbohydrate-, protein-, or fat intake. There is also no difference in energy expenditure or risk in developing an eating disorder, probably due to less competitiveness compared to other international gymnasts. / Thesis (M.Sc. (Dietetics))--North-West University, Potchefstroom Campus, 2005.

Identifying molecular mechanisms regulating cellular energy utilization may lead to increased understanding of maintenance energy cost and improved feed efficiency in beef cows. Three experiments were conducted to characterize measures of residual feed intake (RFI) in pregnant beef cows; to examine the effects of moderate dietary restriction on visceral organ mass and proteins relating to energy metabolism; and to investigate the influence of pregnancy on visceral organ mass and proteins relating to energy metabolism. The first experiment combined data from five experiments using 321 pregnant Angus × Simmental cows. Including ultrasound fat measures and diet/management information increased the feed intake prediction model R2 by 7.3% and > 20%, respectively. Individual experiment RFI models varied greatly in accuracy. In the second experiment, 22 pregnant beef cows were fed at 85% (LOW; n=11) or 140% (HIGH; n=11) of net energy requirements during mid- to late-gestation. Tissue samples from liver, kidney, muscle, ruminal papillae, pancreas, and small intestinal muscosa were collected. Western blots were conducted to quantify abundance of: proliferating cell nuclear antigen, ATP synthase, ubiquitin, and Na/K+ ATPase for all tissues; peroxisome proliferator-activated receptor gamma, peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α), and 5’-adenosine monophosphate-activated protein kinase and phosphorylated-AMPK (pAMPK) for liver, muscle, and rumen; phosphoenolpyruvate carboxykinase for liver and kidney; and uncoupling protein 2 for liver. Cows fed HIGH had greater (P ≤ 0.04) ADG and final BW than cows fed LOW. Ubiquitin abundance in muscle was greater (P = 0.009) in cows fed LOW, and PCG-1α in liver was greater (P = 0.03) in cows fed HIGH. In the third experiment, 18 pregnant (PREG; n =9) or non-pregnant (OPEN; n=9) Angus × Simmental cows were fed for ad libitum intake during mid- to late-gestation. Tissues were weighed and collected and analyzed for protein abundance as described in the second experiment. Liver mass was lower (P ≤ 0.02), abundance of Na+/K+-ATPase was greater (P =0.04) and rumen pAMPK abundance was increased (P = 0.006) in PREG cows. These experiments indicate that measuring RFI in pregnant cows may pose some challenges, and nutrient restriction and pregnancy can influence molecular factors influencing feed efficiency. / Financial support was provided by Canadian Beef Cattle Industry Science Cluster, through funding provided by the Beef Cattle Research Council and Agriculture and Agri-Food Canada, Agriculture Adaptation Council-Farm Innovation Program, Ontario Ministry of Agriculture, Food and Rural Affairs, and the Ontario Cattleman’s Association.

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