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Abstract

Research has elucidated the impact of post-exercise carbohydrate nutrition and environmental conditions on muscle glycogen re-synthesis. However, research has minimally considered the implications of glycogen recovery in females and has mostly focused on commercial sport nutrition products. The purpose of this study was to determine the effects of varied mixed macronutrient feedings on glycogen recovery and subsequent exercise performance in both sexes. Males (n = 8) and females (n = 8) participated in a crossover study. Subjects completed a 90-min cycling glycogen depletion trial, then rested for 4 h. Two carbohydrate feedings (1.6 g kg−1) of either sport supplements or potato-based products were delivered at 0 and 2 h post-exercise. Muscle biopsies (glycogen) and blood samples (glucose, insulin) were collected during the recovery. Afterwards, subjects completed a 20 km cycling time trial. There was no difference between sexes or trials for glycogen recovery rates (male: 7.9 ± 2.7, female: 8.2 ± 2.7, potato-based: 8.0 ± 2.5, sport supplement: 8.1 ± 3.1 mM kg wet wt−1 h−1p > 0.05). Time trial performance was not different between diets (38.3 ± 4.4 and 37.8 ± 3.9 min for potato and sport supplement, respectively, p > 0.05). These results indicate that food items, such as potato-based products, can be as effective as commercially marketed sports supplements when developing glycogen recovery oriented menus and that absolute carbohydrate dose feedings (g kg−1) can be effectively applied to both males and females.

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References

  1. Flynn S, Rosales A, Hailes W, Ruby B. Males and females exhibit similar muscle glycogen recovery with varied recovery food sources. Eur J Appl Physiol. 2020. doi: 10.1007/s00421-020-04352-2
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Abstract

Carbohydrate (CHO) ingestion is an established strategy to improve endurance performance. Race fuels should not only sustain performance, but also be readily digested and absorbed. Potatoes are a whole-food based option that fulfills these criteria yet their impact on performance remains unexamined. We investigated the effects of potato purée ingestion during prolonged cycling on subsequent performance versus commercial CHO gel or a water-only condition. Twelve cyclists (70.7 ± 7.7 kg, 173 ± 8 cm, 31± 9 years, 22 ± 5.1 % body fat; mean ± SD) with average peak oxygen consumption (VO2PEAK)of 60.7 ± 9.0 mL/kg/min performed a 2 h cycling challenge (60-85%VO2PEAK) followed by a time trial (TT, 6kJ/kg body mass) while consuming potato, gel, or water in a randomized-crossover design. The race fuels were administered with U-[13C6]glucose for an indirect estimate of gastric emptying rate. Blood samples were collected throughout the trials. Blood glucose concentrations were higher (P<0.001) in potato and gel conditions when compared to water condition. Blood lactate concentrations were higher (P=0.001) after the TT completion in both CHO conditions when compared to water condition. TT performance was improved (P=0.032) in both potato (33.0 ± 4.5 min) and gel (33.0 ± 4.2 min) conditions when compared to the water condition (39.5 ± 7.9 min). Moreover, no difference was observed in TT performance between CHO conditions (P=1.00). In conclusion, potato and gel ingestion equally sustained blood glucose concentrations and TT performance. Our results support the effective use of potatoes to support race performance for trained cyclists.

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References

  1. Salvador, A.F., McKenna, C.F., Alamilla, R.A., Cloud, R.M.T., Keeble, A.R., Miltko, A., Scaroni, S.E., Beals, J.W., Ulanov, A.V., Dilger, R.N., Bauer, L.L., Broad, E.M., Burd, N.A. (2019). Potato ingestion is as effective as carbohydrate gels to support prolonged cycling performance. Journal of Applied Physiology. doi:10.1152/japplphysiol.00567.2019
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Abstract

Health professionals universally agree on the importance of a balanced diet, and the fallacy of relying on any one or two food groups, as the means of achieving peak physical performance and health. A review of the existing sports nutrition literature indicates that different types of athletes and physically active people may have slightly different nutritional requirements, but the main tenets of sports nutrition have not changed much over the last 25 years. The specific combinations may vary, but carbohydrates, protein, and fluids are vital components of an active individual’s diet. Further, most available research supports the notion that optimal physical performance requires carbohydrate – and, specifically, high-quality, nutrient-dense carbohydrate from whole food sources, like potatoes. High- quality carbohydrate sources – foods that offer an array of macro- and micronutrients as well as energy, can help to build a strong nutritional foundation for the level of training, recovery, and adaptation that most physically active people seek to achieve. Low carbohydrate diets will not generally allow athletes to train at the intensity required to attain peak physical performance.

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References

  1. Kanter M, Elkin C. Potato as a Source of Nutrition for Physical Performance. Am J Potato Res. 2019; 96:201. doi:10.1007/s12230-018-09701-8.
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Abstract

The ability of athletes to train day after day depends in large part on adequate restoration of muscle glycogen stores, a process that requires the consumption of sufficient dietary carbohydrates and ample time. Providing effective guidance to athletes and others wishing to enhance training adaptations and improve performance requires an understanding of the normal variations in muscle glycogen content in response to training and diet; the time required for adequate restoration of glycogen stores; the influence of the amount, type, and timing of carbohydrate intake on glycogen resynthesis; and the impact of other nutrients on glycogenesis. This review highlights the practical implications of the latest research related to glycogen metabolism in physically active individuals to help sports dietitians, coaches, personal trainers, and other sports health professionals gain a fundamental understanding of glycogen metabolism, as well as related practical applications for enhancing training adaptations and preparing for competition.

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References

  1. Murray B, Rosenbloom C. Fundamentals of glycogen metabolism for coaches and athletes. Nutr Rev. 2018; 76(4):243-259. doi:10.1093/nutrit/nuy001.
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Abstract

While all experts agreed that protein needs for performance are likely greater than believed in past generations, particularly for strength training athletes, and that dietary fat could sustain an active person through lower-intensity training bouts, current research still points to carbohydrate as an indispensable energy source for high-intensity performance.

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References

  1. Kanter M. High-Quality Carbohydrates and Physical Performance: Expert Panel Report. Nutri Today. 2018; 53(1):35-39. doi:10.1097/NT.0000000000000238
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