Study on Food Intake and Energy Expenditure During Extreme Sustained Exercise: The Tour de France

Abstract

Food intake and energy expenditure (EE) were studied in five cyclists during the 22-day race of the Tour de France. The course is about 4000 km including 30 mountain passages (up to 2700 m altitude) and can be considered as one of the most strenuous endurance endeavors. Nutritional intake was calculated from daily food records. EE was estimated from sleeping time and the low activity period. EE during cycling was predicted based on detailed information. Mean energy intake (EI) was 24.7 MJ with a highest mean daily EI of 32.4 MJ. Mean EE was 25.4 MJ with a highest mean daily EE of 32.7 MJ. Relative contribution of protein, CHO, and fat was 15, 62, and 23 En% resp. 49% of EI was taken during the race resulting in a CHO intake of 94 g.h-1 representing 69 en%. It is questioned whether this amount of CHO is optimal in relation to CHO oxidation and performance. About 30% from CHO intake came from CHO-rich liquids. High EI resulted in high Ca and Fe intake. For vitamins, especially B1, this relation was not found. Vitamin B1 nutrient density dropped to 0.25 mg/4.2 MJ during the race caused by a large intake of refined CHO-rich food items. However, vitamin supplementation was high. Daily water intake was 6.71 with extremes up to 11.81. Therefore, the strategy of intake of large quantities of CHO-rich liquids seems to be the appropriate answer to maintain energy and fluid balance under these extreme conditions.

Interrelationships between muscle fibre type, substrate oxidation and body fat

“…17 Over the years much work has sought to provide insight into the causes that lead to an accumulation of body fat. It is evident that overall fat balance must be a critical variable to the development of obesity, 18 and since skeletal muscle accounts for some 20 % of total energy expenditure at rest 1 and up to 65 ± 70 % during vigorous physical activity, 19 skeletal muscle must play a role in fat balance. The three muscle ®bre types in man have quite different inherent capacities to utilise fat: Type I signi®cantly more so than type IIb, type IIa being intermediate.…”

Effects of physical activity on food intake

“…15 The purpose of the study was to verify whether the energy intakes of the cyclists were in agreement with the energy expenditure on a race that could be considered as one of the most strenuous endurance activities that exist (4000 km long, including 30 mountain passages (up to 2700 m altitude)). 16 Based on the double-labelled water technique, the cyclists reached an average daily metabolic rate of 4.3-5.3 times basal metabolic rate. The decrease in their body mass and body composition was not considered significant, and all four subjects remained in energy balance ( Fig.…”

“…1, zone 5), as a result of long-term exercise training, increased fatfree mass and consumption of carbohydrate-rich food during exercise. 16,17 Above these values, a human body is not capable to cover the high-energy expenditure with energy intake, and loss of body mass occurs as a consequence, which together with symptoms like fatigue, mood changes and sleep problems constitutes the overtraining syndrome. 18 When regular PA is introduced in the otherwise sedentary population, one would thus expect that the increased energy expenditure accomplished through exercise would rapidly lead to increased dietary intake.…”

Consumo de carboidratos e lipídios no desempenho em exercícios de ultra-resistência

“…Saris et al (1989) 17 , durante o Tour de France (4.000km, com montanhas de até 2.700m de altitude, durante 22 dias), constataram um consumo médio de 5.881kcal, com máxi-mo de 7.714kcal, e um gasto médio de 6.048kcal, com má-ximo de 7.786kcal, em que o consumo de carboidratos correspondeu a 62%, o de gordura a 23% e o de proteína a 15%; 49% do consumo energético foi feito durante as etapas, em que 69% foram provenientes de carboidratos.…”

“…Saris et al (1989) 17 39 estimam que aproximadamente 20 gramas de carboidrato consumido são oxidados durante a primeira hora de exercício; sendo assim, orientam para que os atletas devam consumir cerca de 100ml de uma bebida contendo de 3 a 5% de carboidratos, para depois aumentarem essa concentração para cerca de 10% de carboidratos, a fim de igualar a taxa de oxidação da glicose sanguínea (aproximadamente 1 grama por minuto).…”