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Carbohydrate supplementation
Published in Jay R Hoffman, Dietary Supplementation in Sport and Exercise, 2019
Parker N Hyde, Richard A LaFountain, Carl M Maresh
When viewed in the context of fuelling demands, it starts to become clear how vital metabolic flexibility is to endurance performance. As we learned in the prior section, fuelling is largely driven by exercise intensity and the metabolites and signalling molecules in circulation. We have just discussed a slowly growing body of literature investigating the downstream effects of fuelling, or inadequate fuelling, in the persistence of central fatigue. At this point the reader may be generating hypotheses around the use of carbohydrates in acute supplementation as well as daily dietary intakes for optimal performance.
Type 2 diabetes
Published in John M. Saxton, Exercise and Chronic Disease, 2011
Stephan F. E. Praet, Robert Rozenberg, Luc J. C. Van Loon
The aetiology of insulin resistance and pancreatic β-cell dysfunction has been studied extensively and it has become clear that the key component in the development of type 2 diabetes is inactivity in combination with overeating. In energetic terms this means a chronic positive energy balance or from a physiological point of view chronic metabolic stress (Stumvoll et al., 2005; Kahn et al., 2006; Eriksson, 2007). A persistent caloric overload will cause adipocyte ‘overfilling’ with triacylglycerol in mainly visceral adipose tissue, producing large and dysfunctional adipocytes. This adipocyte dysfunction is characterized by insulin resistance, impairing lipolysis and the ability to clear circulating triacylglycerol. This reduced buffering capacity for fatty acids results in a greater release of free fatty acids and glycerol from adipose tissue into the circulation. The impaired fat oxidative capacity is accompanied by a reduced ability to switch to glucose oxidation in type 2 diabetes, resulting in a state of reduced metabolic flexibility. Persistent high plasma free fatty acid and triacylglycerol levels lead to ectopic fat deposition in skeletal muscle (Boden and Chen, 1995; Boden, 1997) and liver tissue (Kabir et al., 2005) inducing insulin resistance in these tissues and completing the ‘downward spiral’.
Exercise and Dietary Influences on The Regulation of Energy Balance and Implications for Body Weight Control
Published in Peter M. Tiidus, Rebecca E. K. MacPherson, Paul J. LeBlanc, Andrea R. Josse, The Routledge Handbook on Biochemistry of Exercise, 2020
Andrea M. Brennan, Robert Ross
The following factors influence energy storage and body weight: Genetics: There is a strong consensus that genetic influences play a large role in body weight and body composition in addition to responses to intervention. Potential gene targets are beyond the scope of this chapter, but the reader is encouraged to review several comprehensive examinations on the topic (10, 60, 74). Instead, this section will focus on biological and metabolic determinants of body weight and fat distribution.Low metabolic rate: While there is a clear and consistent relationship between metabolic rate and body size, substantial interindividual variability exists, suggesting that individuals who vary in size may also vary in metabolic rate. Indeed, the well-studied Pima Indian population is characterized by low metabolic rates even after adjusting for fat-free mass, fat mass, age, and sex (77). Additionally, over the long term, those with a low REE had a greater risk of weight gain than those with a high REE (31).Metabolic flexibility: Equally important to energy balance is macronutrient balance, specifically, whether the intake of each macronutrient matches its oxidation. The ability of the body to adjust the flux of metabolic pathways in response to changes in macronutrient consumption is defined as metabolic flexibility (31). Metabolic flexibility can be studied using the respiratory quotient (RQ) as an indicator. The RQ represents the ratio of carbohydrate to fat oxidation, with lower fasting values (∼0.80) reflecting a greater reliance on fat for fuel and conversely, higher values (∼1.00) reflecting a greater reliance on carbohydrates (27, 112). Those individuals who rely more heavily on carbohydrates as the substrate for energy production are more likely to gain body weight than those who rely more heavily on fat. In the context of metabolic flexibility, those individuals who are better able to match fuel oxidation to fuel availability decrease their risk of body weight gain.
Microbial adaptation to the healthy and inflamed gut environments
Published in Gut Microbes, 2020
Yijie Guo, Sho Kitamoto, Nobuhiko Kamada
The recent advances in next-generation sequencing and mass spectrometry technologies highlight the metabolic landscape in the development of the gut bacterial ecosystem. As discussed, the bacterial metabolic pathways, which are the key mechanisms that regulate the bacterial community, can be targeted for the editing of the gut microbial community. However, it is noteworthy that bacteria can change their metabolic and nutritional preferences according to the surrounding microenvironment, such as inflammation. The bacterial environment-dependent metabolic flexibility, therefore, needs to be considered before editing the microbiota. For example, the deprivation of key nutrients by modulating the diet can efficiently reduce opportunistic growth and infection by pathogenic bacteria in the steady-state gut. However, the same strategy is ineffective once inflammation has developed, as pathogenic bacteria reprogram their metabolic requirements. Thus, the same treatments, namely dietary interventions, may not be equally effective for different patients, or even for the same individuals who are at distinct stages of disease (e.g., grade of inflammation). On the one hand, metabolic flexibility benefits pathogenic bacteria, enabling the avoidance of metabolic limitations. On the other hand, metabolic flexibility ensures the safety of dietary interventions. Certain metabolic pathways only operate in pathogenic bacteria in certain disease conditions (e.g., inflammation); control and regulation of these pathways has no impact on the bacterial ecosystem in the healthy gut. For example, the l-serine–deficient diet does not affect the fitness of pathogenic E. coli and C. rodentium in the healthy gut, whereas it effectively limits their growth in the inflamed gut.68 Thus, this dietary treatment only impacts the gut microbial community during inflammation, not in the steady state. Clearly, the understanding of bacterial metabolic pathways and their flexibility in disease conditions will advance the development of personalized, disease-specific microbiota editing strategies.
Effects of Betaine Supplementation on Markers of Metabolic Flexibility, Body Composition, and Anaerobic Performance in Active College-Age Females
Published in Journal of Dietary Supplements, 2023
Hunter S. Waldman, Andrea R. Bryant, Matthew J. McAllister
Therefore, the purpose of this study was twofold: (a) to examine the effects of BET supplementation on markers of metabolic flexibility during a graded exercise test (GXT) and body composition and (b) to examine the effects of BET supplementation on markers of anaerobic performance in a female only cohort.
Three Weeks Daily Intake of Matcha Green Tea Powder Affects Substrate Oxidation during Moderate-Intensity Exercise in Females
Published in Journal of Dietary Supplements, 2021
Mark E. T. Willems, Hillary L. Fry, Majeedah A. Belding, Mojtaba Kaviani
Observations from in-vivo studies in humans on the effects of Matcha are limited (e.g. Dietz et al. 2017; Willems et al. 2018). Dietz et al. (2017) reported acute effects of Matcha green tea powder (4 grams) on specific attentional tasks. As far as we know, Willems et al. (2018) is the only study that examined the effects of Matcha consumption and exercise-induced metabolic responses. It was observed that the drinking of four cups of Matcha (three cups the day before and 1cup on the day of testing, each cup made up with 1 gram of Matcha) enhanced fat oxidation by 18% during brisk walking in females and lowered the respiratory exchange ratio (Willems et al. 2018). The respiratory exchange ratio provides the relative contribution of carbohydrate and fat oxidation to total energy expenditure, and a lower value by an intervention is considered to be beneficial as there is more reliance of fat as a substrate. An increase in exercise-induced fat oxidation by a nutritional ergogenic may affect body composition (e.g. decaffeinated green tea extract, Roberts et al. 2015). While the study by Willems et al. (2018) demonstrated short term benefits, the mechanisms for enhanced fat oxidation by green tea extract may differ between short- and long-term intake (Hodgson et al. 2013). In addition, for individuals to respond to supplement-induced fat oxidation during exercise may affect their metabolic flexibility (see Hodgson et al.2013). No studies have examined the effects of long-term intake of Matcha on the metabolic and physiological responses during moderate-intensity exercise. In addition, resting fat oxidation has been correlated with body mass index after 4-weeks intake of capsinoids (Inoue et al. 2007). However, the relationship between body fat percentage and potential to enhance exercise-induced fat oxidation by green tea intake has not been examined. The primary aim of the present study was to examine the effects of intake of Matcha green tea powder over 3weeks on fat oxidation during moderate-intensity exercise in females. The secondary aim was to examine whether body fat percentage was related to the Matcha response on exercise-induced fat oxidation.