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Fat
Published in Christopher Cumo, Ancestral Diets and Nutrition, 2020
Yet physiology rebuts this view because our cells are most efficient at digesting and metabolizing carbohydrates, which the body prefers as energy.29 For example and as Chapter 2 mentioned, the body absorbs between 97 and 99 percent of carbohydrates it ingests, but 95 percent of fat and 92 or 93 percent of protein.30 Like other cells, those in the brain metabolize the sugar glucose (C6H12O6)—Chapter 2 described its manufacture, structure, and metabolism—a carbohydrate. In this context, American nutritionist and dietician Stephanie Green estimated that the brain requires between 50 and 100 grams of carbohydrates daily.31 Only inadequacy compels it to metabolize fat. Because the body is less efficient at metabolizing fat or protein, the body prefers to metabolize carbohydrates rather than store them while doing the reverse with fat. Endurance athletes apply this knowledge when they consume carbohydrate-rich foods, a practice known as carbohydrate loading, before competition.32 The outcome of this metabolic bias in favor of carbohydrates is the body’s small supply of glycogen relative to adipose when calories are in excess.33 Moreover and as Chapter 2 noted, fat metabolism’s inefficiency is evident in that the body requires more oxygen to metabolize a gram of fat than a gram of carbohydrates. From an evolutionary perspective, humans must have adapted to an environment that supplied carbohydrates, not fat or protein, as the primary macronutrient.
Nutritional Ergogenic Aids — Macronutrients
Published in Luke Bucci, Nutrients as Ergogenic Aids for Sports and Exercise, 2020
It is now clear that the availability of carbohydrates to muscles is a limiting factor for prolonged, strenuous exercise.37,48–51 Carbohydrates are presented to muscles primarily as the monosaccharide glucose, with minor contributions from glycerol and other sugars. Storage of glucose is found mainly in liver and muscles as a branched-chain polymer named glycogen. When muscle glycogen stores are depleted and blood glucose levels are significantly lowered, fatigue results.37,51 Since carbohydrates are the major source of energy at exercise intensities of ≥70% VO2max and are about 50% of energy sources at lower intensities,52 carbohydrate availability to exercising muscles is obviously of paramount importance for maintenance of performance. Thus, loss of carbohydrates ranks directly behind dehydration and loss of electrolytes as a major cause of fatigue. Carbohydrate status is directly related to dietary intake rather than other variables. Thus, nutritional modulation of carbohydrate status has been explored in some detail in order to enhance or prolong performance. Increasing duration of carbohydrate availability to exercising muscles can be accomplished by increasing glycogen storage above usual amounts, termed glycogen supercompensation, or more popularly, carbohydrate loading.
Some other groups and circumstances
Published in Geoffrey P. Webb, Nutrition, 2019
Maximising the glycogen stores in muscle and liver are now seen as key elements in the preparation for competition in endurance sports (i.e. longer than 1 h of sustained heavy exercise). In some endurance sports it may also be possible to take in extra carbohydrate during the event. In experimental studies, the maximum duration for which heavy exercise (75% of VO2max) can be sustained is directly proportional to the glycogen content of the muscle at the start. Exhaustion occurs when the muscle glycogen reserves are completely depleted. High carbohydrate diets (70% of energy) during training increase the muscle glycogen content and so increase the maximum duration that heavy exercise can be sustained. In their position statement Rodriguez et al. (2009) suggested that in diets for athletes, fat should provide 20–35% of the energy (i.e. 75–80% from protein and carbohydrate) but that less than 20% of energy from fat offered no health or performance benefits. This moderate level of fat should provide adequate amounts of essential fatty acids and fat-soluble vitamins and help provide adequate energy for weight maintenance. Many endurance athletes manipulate their diets and exercise schedules prior to competition in an attempt to increase their body glycogen stores, so-called carbohydrate loading. This extra carbohydrate also increases muscle water content which may not be advantageous for those in explosive events where the size of muscle glycogen stores are not critical.
Knowledge of enhanced recovery after surgery and influencing factors among abdominal surgical nurses: a multi-center cross-sectional study
Published in Contemporary Nurse, 2022
Bing Xue, Huidan Yu, Xianwu Luo
There is potential for improvement in implementation in certain aspects of ERAS protocols. The results of this study showed that more than half of the participants still adhered to traditional carbohydrate loading requirements, while there is sufficient evidence that the use of carbohydrate loading two hours before surgery has metabolic benefits and reduces insulin resistance after surgery (Talutis et al., 2020). Carbohydrate loading two hours before surgery can avoid starvation, allow patients to reserve a certain amount of energy before surgery, promote insulin secretion, improve postoperative insulin sensitivity, and thus improve postoperative insulin resistance (Gumus et al., 2021). Moreover, the incidence of perioperative complications can also be significantly reduced. Nurses’ perceptions of perioperative carbohydrate loading lag behind current evidence, and their knowledge is not kept up to date, which may hinder the implementation of ERAS protocol (Brown & Xhaja, 2018; Lyon et al., 2014).
The impact of nutritional status on pancreatic cancer therapy
Published in Expert Review of Anticancer Therapy, 2022
Gabriele Capurso, Nicolò Pecorelli, Alice Burini, Giulia Orsi, Diego Palumbo, Marina Macchini, Roberto Mele, Francesco de Cobelli, Massimo Falconi, Paolo Giorgio Arcidiacono, Michele Reni
Among ERP nutritional interventions, limiting preoperative fasting to 6 hours for solids and 2 hours for clear liquids before induction of anesthesia is important in order to attenuate insulin resistance induced by prolonged fasting. Carbohydrate loading administered a few hours before surgery has been proposed as a measure to increase glycogen storage and decrease insulin resistance. The PROCY RCT compared carbohydrate loading and placebo in 800 non-diabetic patients undergoing major abdominal surgery. They found no difference in postoperative morbidity and infection rate however, the control group required significantly more insulin postoperatively confirming the role of this intervention in blunting perioperative insulin resistance and maintaining euglycemia [65]. There is currently limited evidence on carbohydrate loading in pancreatic surgery, but it would be important to evaluate if it can increase insulin sensitivity in this setting considering the significant number of diabetic patients undergoing resection.
Benzonate derivatives of acetophenone as potent α-glucosidase inhibitors: synthesis, structure–activity relationship and mechanism
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2019
Wen-Jia Dan, Qiang Zhang, Fan Zhang, Wei-Wei Wang, Jin-Ming Gao
The carbohydrate loading test was conducted according as Kato et al.23 and Han et al.24 reported, with slight modifications. Fifteen male Kunming mice (35–40 g) after an overnight fast were randomly divided into three groups (five mice per group). Sucrose (2.5 g/kg body weight), as well as the tested compound 7u (20 mg/kg body weight) and acarbose (20 mg/kg body weight) were dissolved in 0.5% sodium carboxymethyl cellulose (CMC–Na) solution, then administered to mice via a gavage method, respectively. A blank control group was loaded with 0.5% CMC–Na solution only. The blood samples were collected from the mice’s tail vein at 0, 15, 30, 60, 90, and 120 min, and the blood glucose levels were determined by a glucose detection kit.