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.

Key words

energy expenditure - food intake - endurance athletes - cycling - carbohydrate metabolism - vitamins