Timing of Energy and Fluid Intake

The traditional view of energy and nutrient delivery is to provide recommendations in units of 24 hours. Although these guidelines may be useful for some people, they are inadequate for athletes wishing to optimize fuel and fluid delivery to enhance performance. Put simply, the dynamics of energy and fluid intake should match the dynamics of energy and fluid usage. Any delivery system that deviates widely from this principle can't help athletes train and perform at their best. Studies have shown that matching intake and expenditure dynamics helps athletes maintain lean mass, reduce body fat levels, improve sense of well-being, and enhance athletic performance. This chapter provides a critical summary of studies that have looked at within-day energy balance and eating frequency and the underlying physiological and nutrition principles that show the importance of reducing the magnitude of energy surpluses and deficits during the day. In addition, the chapter provides practical strategies for how athletes involved in morning and afternoon, afternoon and evening, or one-time daily training regimens can sustain an optimal within-day energy and fluid balance.

Exercise has two major effects on the requirement for nutrients. It results in an increase in the rate of energy usage and, because of the greater heat production associated with higher levels of energy metabolism, an increase in the rate of water lost as sweat. Athletes must increase energy substrate and fluid consumption to meet this additional nutrition burden, yet nutrition surveys suggest that athletes don't eat enough and don't drink enough.^1-3 Moreover, it appears that energy consumption is not well timed, which negatively affects both body composition and performance.^4-6

The outcome of this widespread athletic malnutrition is all too well understood: an excessive reliance on supplements and ergogenic aids to overcome the deficits created by inadequate energy and fluid consumption. Athletes will likely achieve better results by paying attention to food and drink intake than by following any other course of action. Focusing on food and drink is a less expensive, more dependable, and safer strategy for improving athletic performance than relying on supplements and ergogenic aids, which may have indefinite content and unpredictable quality.

Fuel For The Final 5 Kilometers

Intake For Performance Enhancement

Carbohydrate Loading

Seven Day Wrap-Up