Effect of breakfast omission on subjective appetite, metabolism, acylated ghrelin and GLP-17-36 during rest and exercise

Breakfast omission induces compensatory eating behaviour at lunch, but often reduces daily energy intake. This study investigated the effect of breakfast omission on within-day subjective appetite, energy expenditure, substrate utilisation and appetite hormone profiles, in response to standardised feeding and exercise. Eight male, habitual breakfast eaters completed two randomised trials. Subjects arrived overnight fasted (0h), and either consumed (BC) or omitted (BO) a standardised breakfast (Mean (SD) (3085 (217) kJ). Lunch (4162 (510) kJ) and dinner (4914 (345) kJ) were provided at 4.5 and 10 h, respectively and subjects performed 60 min fixed-intensity cycling (50% VO 2 peak) at 8h. Blood samples were collected at 0, 4.5, 6 and 8 h, with expired air and subjective appetite sensations (hunger, fullness, desire to eat (DTE) and prospective food consumption (PFC)) collected throughout. Heart rate and perceived exertion were m easured during exercise. Hunger, DTE and PFC were greater and fullness lower during BO (P0.193). Resting energy expenditure was greater at 2.5 h during BC (P0.156). GLP-1 7-36 was greater (P<0.05) and acylated ghrelin tended to be greater (P=0.078) at 4.5 h during BC. Heart rate was greater on BO (P<0.05) during exercise. The results of this laboratory-controlled study suggest that the effects of breakfast omission are transient and do not extend beyond lunch, even when the negative energy balance created by breakfast omission is sustained via standardised feeding and exercise

The effect of post-exercise drink macronutrient content on appetite and energy intake

Carbohydrate and protein ingestion post-exercise are known to facilitate muscle glycogen resynthesis and protein synthesis, respectively, but the effects of post-exercise nutrient intake on subsequent appetite are unknown. This study aimed to investigate whether protein induced satiety that has been reported at rest was still evident when pre-loads were consumed in a post-exercise context. Using a randomized, double blind, crossover design, 12 unrestrained healthy males completed 30 min of continuous cycling exercise at ~60% VO2peak, followed by five, 3 min intervals at ~85% VO2peak. Ten min post-exercise, subjects consumed 500 ml of either a low energy placebo (15 kJ) (PLA); a 6% whey protein isolate drink (528 kJ) (PRO); or a 6% sucrose drink (528 kJ) (CHO). Sixty min after drink ingestion, a homogenous ad-libitum pasta lunch was provided and energy intake at this lunch was quantified. Subjective appetite ratings were measured at various stages of the protocol. Energy consumed at the ad-libitum lunch was lower after PRO (5831 ± 960 kJ) than PLA (6406 ± 492 kJ) (P0.315). Considering the post-exercise drink, total energy intake was not different between trials (P=0.383). There were no differences between trials for any of the subjective appetite ratings. The results demonstrate that where post-exercise liquid protein ingestion may enhance the adaptive response of skeletal muscle, and this may be possible without affecting gross energy intake relative to consuming a low energy drink

The effect of breakfast on appetite regulation, energy balance and exercise performance

The belief that breakfast is the most important meal of day has been derived from cross-sectional studies that have associated breakfast consumption with a lower BMI. This suggests that breakfast omission either leads to an increase in energy intake or a reduction in energy expenditure over the remainder of the day, resulting in a state of positive energy balance. However, observational studies do not imply causality. A number of intervention studies have been conducted, enabling more precise determination of breakfast manipulation on indices of energy balance. This review will examine the results from these studies in adults, attempting to identify causal links between breakfast and energy balance, as well as determining whether consumption of breakfast influences exercise performance. Despite the associations in the literature, intervention studies have generally found a reduction in total daily energy intake when breakfast is omitted from the daily meal pattern. Moreover, whilst consumption of breakfast supresses appetite during the morning, this effect appears to be transient as the first meal consumed after breakfast seems to offset appetite to a similar extent, independent of breakfast. Whether breakfast affects energy expenditure is less clear. Whilst breakfast does not seem to affect basal metabolism, breakfast omission may reduce free-living physical activity and endurance exercise performance throughout the day. In conclusion, the available research suggests breakfast omission may influence energy expenditure more strongly than energy intake. Longer term intervention studies are required to confirm this relationship, and determine the impact of these variables on weight management

Defining and estimating value to a mission

Selection of assignments for a constrained inventory of assets and associated services requires comparable measures of their value to the potential recipients, and any associated costs. The dissemination of information or intelligence products over bandwidth limited and security constrained channels similarly requires consideration of the associated values and costs. Similar reasoning is applicable to the selection of variant effects and methods. We present an approach to value definition and prediction in the mission performance characteristics resulting from variant deployments

Holy or unholy matrimony: does participation in a pre-college program influence the retention rate of African American males in college

Fifty percent of all students who enroll in college depart before earning their degree; this proportion is even higher among minorities during the first year of college (Tinto, 2006). Minorities have typically had fewer opportunities to gain a college education. Once enrolled in college, minorities have generally found it more difficult to succeed academically and graduate (Strayhorn, 2011). There is one group among the collective of minorities that are even further behind the rest, African American males. African American males are one of the most underrepresented populations of students on college campuses around the nation (Feagin, Vera, & Imani, 1996). Relatively few Black men enroll in four-year colleges and universities (Cuyject, 2006); in fact, of the approximate 15 million undergraduate students in the United States, less than 5% are Black men (NCES, 2009). In response to the trends and challenges faced by Black men, the federal government, as well as higher education institutions, have invested considerable resources in the development and implementation of programs and services that are designed to provide the necessary academic and social support researchers have found to be integral to the success of students in college (Astin, 1993; Swail, Redd & Perna, 2003 and Tinto, 1993). One of the federal government’s responses to this issue is the development of numerous pre-college programs. The aim of this study was to determine whether pre-college programs (i.e., Upward Bound, Talent Search & G.E.A.R. UP) are effective in realizing their goals for African American men, particularly as it relates to their college retention rates. Using the National Center for Education Statistics’ Education Longitudinal Study of 2002 (ELS:2002) guided by Tinto’s Student Attrition model, the researcher sought to determine: To what extent does participating in a pre-college program influence the first-year retention rates of African American males in college, controlling for differences in, background traits, academic preparedness and parental level of education? The findings from this study suggest that out of three federally funded pre-college programs Upward Bound, Talent Search and G.E.A.R. UP, only the Talent Search program has any impact on the retention rate of African American males in college

The evolution of parental care in insects: A test of current hypotheses.

Which sex should care for offspring is a fundamental question in evolution. Invertebrates, and insects in particular, show some of the most diverse kinds of parental care of all animals, but to date there has been no broad comparative study of the evolution of parental care in this group. Here, we test existing hypotheses of insect parental care evolution using a literature-compiled phylogeny of over 2000 species. To address substantial uncertainty in the insect phylogeny, we use a brute force approach based on multiple random resolutions of uncertain nodes. The main transitions were between no care (the probable ancestral state) and female care. Male care evolved exclusively from no care, supporting models where mating opportunity costs for caring males are reduced-for example, by caring for multiple broods-but rejecting the "enhanced fecundity" hypothesis that male care is favored because it allows females to avoid care costs. Biparental care largely arose by males joining caring females, and was more labile in Holometabola than in Hemimetabola. Insect care evolution most closely resembled amphibian care in general trajectory. Integrating these findings with the wealth of life history and ecological data in insects will allow testing of a rich vein of existing hypotheses.We thank S. T. Trumbo, D. Lukas, and T. L. Gluckman for advice and helpful comments on the manuscript; K. Isvaran, S. Qader, S. Ho, L. Revell, R. Maia, R. FitzJohn, and A. Meade for invaluable statistical advice; A. Seago, G. Dury, B. Kranz, and L. A. Mound for points of information; andO.F. Time for solving all problems. This studywas funded by BBSRC studentship 02/A1/S/8091 to JDJG. The authors declare no conflicts of interest.This is the final published version. It was first made available by Wiley at http://onlinelibrary.wiley.com/doi/10.1111/evo.12656/suppinfo

Effect of breakfast omission on energy intake and evening exercise performance

Introduction: Breakfast omission may reduce daily energy intake. Exercising fasted impairs performance compared with exercising after breakfast, but the effect breakfast omission has on evening exercise performance is unknown. This study assessed the effect of omitting breakfast on evening exercise performance and within-day energy intake. Methods: Ten male, habitual breakfast eaters completed two trials in a randomized, counterbalanced order. Subjects arrived at the laboratory in an overnight-fasted state and either consumed or omitted a 733 ± 46 kcal (3095 ± 195 kJ) breakfast. Ad libitum energy intake was assessed at 4.5 h (lunch) and 11 h (dinner). At 9 h, subjects completed a 30-min cycling exercise at approximately 60% V˙O2peak, followed by a 30-min maximal cycling performance test. Food was not permitted for subjects once they left the laboratory after dinner until 0800 h the following morning. Acylated ghrelin, GLP-1(7–36), glucose, and insulin were assessed at 0, 4.5, and 9 h. Subjective appetite sensations were recorded throughout. Results: Energy intake was 199 ± 151 kcal greater at lunch (P < 0.01) after breakfast omission compared with that after breakfast consumption and tended to be greater at dinner after consuming breakfast (P = 0.052). Consequently, total ad libitum energy intake was similar between trials (P = 0.196), with 24-h energy intake 19% ± 5% greater after consuming breakfast (P < 0.001). Total work completed during the exercise performance test was 4.5% greater after breakfast (314 ± 53 vs 300 ± 56 kJ; P < 0.05). Insulin was greater during breakfast consumption at 4.5 h (P < 0.05), with no other interaction effect for hormone concentrations. Conclusions: Breakfast omission might be an effective means of reducing daily energy intake but may impair performance later that day, even after consuming lunch