title: Energy intakes of ultraendurance cyclists during competition, an observational study.
abstract: Endurance events>10 hr are becoming increasingly popular but provide numerous physiological challenges, several of which can be attenuated with optimal nutritional intakes. Previous studies in ultraendurance races have reported large energy deficits during events. The authors therefore aimed to assess nutritional intakes in relation to performance among ultraendurance cyclists. This observational study included 18 cyclists in a 384-km cycle race. At race registration each cyclist's support crew was provided with a food diary for their cyclist. On completion of the race, cyclists were asked to recall their race food and drink intakes. All food and fluids were analyzed using a computer software package. Mean (SD) time to complete the race was 16 hr 21 min (2 hr 2 min). Mean (SD) energy intake was 18.7 (8.6) MJ, compared with an estimated energy requirement for the race of 25.5 (7.4) MJ. There was a significant negative relationship between energy intake and time taken to complete the race (p=.023, r²=-.283). Mean (SD) carbohydrate, fat, and protein intakes were 52 (27), 15.84 (56.43), and 2.94 (7.25) g/hr, respectively. Only carbohydrate (p=.015, r²=-.563) and fat intake (p=.037, r²=-.494) were associated with time taken to complete the race. This study demonstrates the difficulties in meeting the high energy demands of ultraendurance cycling. The relationship between energy intake and performance suggests that reducing the energy deficit may be advantageous. Given the high carbohydrate intakes of these athletes, increasing energy intake from fat should be investigated as a means of decreasing energy deficits.
authors.affiliation: Department of Human Nutrition, University of Otago, Dunedin, New Zealand.
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Black
authors.forename: Paula M L
authors.initials: PM
authors.lastname: Skidmore
authors.forename: Rachel C
authors.initials: RC
authors.lastname: Brown
mesh_terms: D000328:Adult; D000368:Aged; D054874:Athletic Performance / Q000502:physiology*; D001642:Bicycling; D015930:Diet Records; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D019587:Dietary Supplements; D002149:Energy Intake; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D058573:Performance-Enhancing Substances / Q000008:administration & dosage; D010807:Physical Endurance / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*; D013312:Stress, Physiological; D015431:Weight Loss
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D058573:Performance-Enhancing Substances