Metabolic adaptation to weight loss: implications for the athlete

Abstract Optimized body composition provides a competitive advantage in a variety of sports. Weight reduction is common among athletes aiming to improve their strength-to-mass ratio, locomotive efficiency, or aesthetic appearance. Energy restriction is accompanied by changes in circulating hormones, mitochondrial efficiency, and energy expenditure that serve to minimize the energy deficit, attenuate weight loss, and promote weight regain. The current article reviews the metabolic adaptations observed with weight reduction and provides recommendations for successful weight reduction and long term reduced-weight maintenance in athletes

Methods and Costs for Pond-Catchment Rehabilitation on the Borana Plateau

The Borana Plateau is an important rangeland for Ethiopia. One key limitation for people and livestock is lack of drinking water. Hundreds of ponds are important water sources for most of the year. Pond catchments are poorly managed because livestock access is uncontrolled. Catchments are stripped bare of vegetation due to trampling and heavy grazing, and unprotected soil is prone to erosion. When the rains come the ponds quickly fill with sediment. Sedimentation reduces pond holding capacity and much labor is required to clean them out. As part of a pilot research project we rehabilitated four ponds and their immediate catchment using a combination of: (1) Perimeter bush-fencing to confine livestock access to a few narrow corridors leading to the water\u27s edge; (2) erosion control using dams and trenches to capture sediment prior to it entering the ponds; and (3) pond de-sedimentation using human labor. In tandem these methods have completely renovated the four sites in less than two years and could be adopted by the pastoralists. Here we report how we implemented each method as well as estimate the total cost of rehabilitation. Overall, the average cost to rehabilitate one seven-hectare pond catchment was 283, 045 Ethiopian Birr (or USD $14,152) including cash and in-kind sources. Costs were almost entirely labor. The largest outlay was for de-sedimentation at 87 percent of total costs on average, followed by erosion control (9 percent) and bush fencing (4 percent). If all 162 ponds in our study area were rehabilitated the cost would exceed 46 million Birr; this might be defrayed if communities can donate some of the labor. The high cost of rehabilitation illustrates that poor catchment management has major economic consequences that undermine system sustainability. Cost data also reveal that a small investment in preventing sedimentation via bush-fencing, grazing management, and erosion control would yield high returns in terms of reducing the need for regular, and expensive de-sedimentation via manual labor

beta-Hydroxy-beta-methylbutyrate free acid reduces markers of exercise-induced muscle damage and improves recovery in resistance-trained men

The purpose of the present study was to determine the effects of short-term supplementation with the free acid form of beta-hydroxy-beta-methylbutyrate (HMB-FA) on indices of muscle damage, protein breakdown, recovery and hormone status following a high-volume resistance training session in trained athletes. A total of twenty resistance-trained males were recruited to participate in a high-volume resistance training session centred on full squats, bench presses and dead lifts. Subjects were randomly assigned to receive either 3 g/d of HMB-FA or a placebo. Immediately before the exercise session and 48 h post-exercise, serum creatine kinase (CK), urinary 3-methylhistadine (3-MH), testosterone, cortisol and perceived recovery status (PRS) scale measurements were taken. The results showed that CK increased to a greater extent in the placebo (329%) than in the HMB-FA group (104%) (P=0.004, d=1.6). There was also a significant change for PRS, which decreased to a greater extent in the placebo (9.1 (SEM 0.4) to 4.6 (SEM 0.5)) than in the HMB-FA group (9.1 (SEM 0.3) to 6.3 (SEM 0.3)) (P=0.005, d = -0.48). Muscle protein breakdown, measured by 3-MH analysis, numerically decreased with HMB-FA supplementation and approached significance (P=0.08, d = 0.12). There were no acute changes in plasma total or free testosterone, cortisol or C-reactive protein. In conclusion, these results suggest that an HMB-FA supplement given to trained athletes before exercise can blunt increases in muscle damage and prevent declines in perceived readiness to train following a high-volume, muscle-damaging resistance-training session

Changes in body composition and performance with supplemental HMB-FA+ATP (Manuscript Clarification)

Additional co-authors: Matthew D. Vukovich, Colin Wilborn, and Darryn S. Willoughb

Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo

Meeting Abstracts: Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo Clearwater Beach, FL, USA. 9-11 June 201

Leucine is a critical factor determining protein quantity and quality of a complete meal to initiate muscle protein synthesis

Emerging research suggests that high protein diets may have a role in preventing obesity, sarcopenia, diabetes, and optimizing muscle mass and bone health. Evidence is mounting that these benefits may be in part due to the amino acid leucine (leu) and its unique ability to stimulate muscle protein synthesis (MPS). Current dietary protein recommendations for protein quantity and quality are defined as the minimum daily amount to prevent deficiencies of limiting amino acids and increases in plasma amino acids are regarded as ‘excess’ or inefficient use of amino acids due to increased amino acid oxidation. This view does not account for the meal responses of MPS associated with intracellular signaling in response to increasing plasma leu. The goal of this research was to elucidate the physiological role that leu plays in complete meals and to determine if the meal distribution of protein or leu is important for optimization of muscle mass. My hypothesis was that optimum MPS would equate to maximum signaling response of the kinase known as mammalian target of rapamycin (mTOR) and directly related to post-prandial plasma leu concentration. Ultimately, the leu content of individual meals and the number of meal per day with sufficient leu to increase MPS will influence muscle mass, lean body mass and long term body composition In vivo work with purified solutions established that leu has a regulatory role for initiating MPS by activating mTOR and there is a clear threshold of leu required to increase plasma leu and stimulate MPS. In order to test the role of leu in complete meals we examined the duration and peak activation of MPS and mTOR signaling in response to complete test meals containing 10, 20, and 30% of total energy from wheat and whey protein (6.8 and 10.9% leu) respectively. We determined that whey increased plasma leu, mTOR signaling, and MPS more than wheat at all protein intakes. Stimulation of MPS after meals last for 3 hours with a peak at 90 minutes, however plasma leu and mTOR signaling remained at a plateau for 3 hours before decreasing. Meal leu content and the increases in postprandial plasma leu were closely associated with peak activation of mTOR signaling and MPS but did not determine the duration of protein synthesis which demonstrated a refractory response to the constant elevations in plasma leu. Experiment 2 examined the potential to use leu to predict the quality of individual proteins to stimulate mTOR signaling and MPS. Adult rats were adapted for 2 weeks to a meal-feeding protocol with complete diets containing 16% protein but with different leu contents using wheat, soy, egg, or whey proteins (6.8, 8.0, 8.8, and 10.9% leu). Animals fed egg and whey significantly increased plasma leu and MPS whereas animals fed wheat and soy did not. The leu content of the meals predicted mTOR signaling and peak MPS responses and were closely related to changes in plasma leu. These findings support the hypothesis that there is a meal leu threshold for increasing plasma leu. While experiment 2 provided proof of concept that there is a meal threshold for leu stimulation of MPS, the critical outcomes are changes in muscle mass or body composition. This study tested the hypothesis that long-term meal-feeding of isonitrogenous/isocaloric diets with 16/54/30% of energy from protein/carbohydrates/lipids, respectively, using protein sources (wheat, soy, egg, whey) with different leu contents could produce body composition and muscle weight outcomes in relation to the changes in postprandial MPS and plasma leu observed in the previous experiments. Based on the leu threshold observed in the previous experiment, the diets were designed such that animals fed egg and whey proteins would receive sufficient leu during each of the three meals to achieve three stimulations of MPS per day as opposed to animals fed wheat and soy proteins with lower leu contents that would achieve the leu threshold only at the larger dinner meal. After 11 weeks of meal-feeding, body composition, lean body mass, and gastrocnemius muscle weights were positively related to the leu content of the diet and reflected the ability of the respective diets to increase postprandial plasma leu and MPS. Finally, we tested the hypothesis that long-term distribution of protein/leu could make a difference in body composition by feeding isocaloric/isonitrogenous meals containing whey protein evenly distributed to achieve the leu thresholds at each of 3 meals (ED-Whey) daily or unevenly distributed over 3 meals (UD-Whey) with only the dinner meal exceeding the leu threshold. The ED-Whey treatment with evenly distributed leu produced multiple stimulations of MPS throughout the day and larger gastrocnemius muscle weights compared to the UD-whey that only achieved stimulation of MPS at a single meal. While muscle mass was larger in the ED-Whey treatment, total lean body mass was not different between groups. This may have been due to the large protein (i.e. nitrogen) content of the dinner meal in the UD-Whey group producing a shift in lean body mass deposition to the liver and visceral tissues, which were larger in the UD-Whey group. In summary, the leu content of complete meals is an important regulator of MPS and produces different body composition outcomes with long term feeding of diets differing in leu contents and leu/protein distribution. These results cannot be explained by limiting amino acids and are not accounted for by current protein quantity and quality recommendations

Chapter 03: Ecology and Natural Resources of San Jose Llanga

Development and change in traditional societies is strongly affected by interactions between humans and their natural environments. Management practices used by most low-input, rural societies represent an amalgamation of technologies, social rules and organisational structures that have been tested over time and found suitable for sustainable exploitation of resources. In many cases, however, changes in population, social values, market opportunities, government policies or technology alter a delicate balance between humans and sustainable resource use. Given these critical relationships, a thorough knowledge of the biophysical environment is essential to comprehend and attempt to improve low-input production systems such as SJL. Our overall purpose in this chapter is to characterise the environment and natural resources of the Cantón of SJL. This is accomplished in two steps. First the climate, surficial geology, hydrology, soils and vegetation are described. Descriptions include brief accounts of land use (i.e., cultivation, grazing, fuel wood collection, etc.) for broadly defined geomorphic units. Second, an analysis is presented concerning selected aspects of ecosystem dynamics at various spatial and temporal scales.https://digitalcommons.usu.edu/sustaining_agropastoralism/1002/thumbnail.jp

The Effects of a Sports Nutrition Education Intervention on Nutritional Status, Sport Nutrition Knowledge, Body Composition, and Performance during Off Season Training in NCAA Division I Baseball Players

This study investigated the effects of a sport nutrition education intervention (SNEI) on dietary intake, knowledge, body composition, and performance in NCAA Division I baseball players. Resistance trained NCAA Division I baseball players (82.4 ± 8.2 kg; 1.83 ± 0.06 m; 13.7 ± 5 % body fat) participated in the study during 12 weeks of off-season training. Fifteen players volunteered for SNEI while 15 players matched for position served as controls (C) for body composition and performance. The nutrition intervention group (NI) received a 90 min SNEI encompassing energy intake (Kcal), carbohydrate (CHO), protein (PRO), fat, food sources, and hydration. Sport nutrition knowledge questionnaires were administered to NI pre and post. Nutritional status was determined by three-day dietary logs administered to NI pre and post. Body composition and performance (5-10-5 shuttle test, vertical jump, broad jump, 1 RM squat) were measured pre and post for C and NI. Knowledge increased in NI. Pro and fat, but not CHO intake increased in NI. FM decreased pre to post in NI (11.5 ± 4.8 vs. 10.5 ± 5.4 kg) but not C (11.3 ± 4.7 vs. 11.9 ± 4.5 kg). FFM increased pre to post with no differences between groups. The 5-10-5 shuttle times decreased significantly more in NI (4.58 ± 0.15 vs. 4.43 ± 0.13 sec) compared to C (4.56 ± 0.18 vs. 4.50 ± 0.16 sec). Jump and squat performance increased pre to post with no differences between groups. Our findings indicate that an off season SNEI is effective at improving sport nutrition knowledge and some, but not all, nutrient intakes and performance measures in Division I baseball players

Sieve Structures to Control Gully Erosion on the Borana Plateau

Gully erosion is a widespread problem in the Borana plateau. Gullies are the main pathway for sediment accumulation in community ponds, especially during heavy rains, which reduces pond capacity. Sediment movement in gullies can be substantially reduced by installation of sieve structures that slow down water flows and allow sediment to settle out of suspension. Sieves can be easily constructed from trees by community labour at low cost. The community should develop a landscape-level plan and follow a suitable sieve design. Project Kalo collaborators have demonstrated that a series of sieve structures down a secondary gully in the Dikale pond enclosure can effectively trap sediment. The main gullies feeding ponds have large catchments generating rushing flood-waters that destroy sieve structures downstream. The appropriate, comprehensive treatment is to begin at the gully head with brush barriers to steer overland flows away from the gully, and branch layers to protect the head cut itself. When gully head treatments are accompanied by a series of sieves in the main channel, gully erosion can be arrested, gully floor and walls revegetated and sediement captured. This approach has been validated by OARI colleagues at the Kobo Watershed gully and on a degraded portion of the Beke pond catchment. It has also proven successful in small channels at Dikale and other enclosures

Intermittent Dieting: Theoretical Considerations for the Athlete

Athletes utilise numerous strategies to reduce body weight or body fat prior to competition. The traditional approach requires continuous energy restriction (CER) for the entire weight loss phase (typically days to weeks). However, there is some suggestion that intermittent energy restriction (IER), which involves alternating periods of energy restriction with periods of greater energy intake (referred to as ‘refeeds’ or ‘diet breaks’) may result in superior weight loss outcomes than CER. This may be due to refeed periods causing transitory restoration of energy balance. Some studies indicate that intermittent periods of energy balance during energy restriction attenuate some of the adaptive responses that resist the continuation of weight and fat loss. While IER—like CER—is known to effectively reduce body fat in non-athletes, evidence for effectiveness of IER in athletic populations is lacking. This review provides theoretical considerations for successful body composition adjustment using IER, with discussion of how the limited existing evidence can be cautiously applied in athlete practice