To eat (or not to eat) before morning training – that is the question!

The Introductionmorning cyclist

Many athletes young and old train first thing in the morning. The question is often asked – should I shouldn’t I eat before those training sessions? There is some research evidence to say that minimising the amount of carbohydrate we take in before endurance training may accelerate the training adaptations such as using fat as an energy source and preserving carbohydrate stores. The aim of this study was to compare the adaptations to endurance training undertaken following either an early morning feed or an overnight-fasted state followed by no breakfast. The results suggest benefits – for men at least!

The Research

Eight female and six male untrained, healthy participants (26.6±5.8 years; 75.3±11.4 kg) were randomly divided into two training groups and undertook four weeks of five days per week endurance cycle ergometer training (moderate intensity increased from 5-10 minutes per session to 25 minutes per session) in either the overnight-fasted (water only) or fed (normal breakfast cereal 60 minutes before training) states. Each group did a VO2 max test before and after the research intervention as well as a muscle biopsy in the thigh to measure muscle carbohydrate stores (glycogen) and enzymes used to generate aerobic energy from fat and carbohydrate.

The Results

Training-induced changes in the muscle enzymes were not different between training groups but when the effect of gender was considered, men responded better to fasting and women responded better to having breakfast before training. In both men and women, the overnight fasting group showed a significantly greater training-induced increase in VO2 max and resting muscle glycogen concentration than the breakfast group but there was no effect of gender.

The So What?

In conclusion, these results suggest that: (a) not eating prior to morning appears to give better adaptations to endurance training – at least in non-athletes; and (b) the extent of these adaptations in skeletal muscle differ slightly between men and women with men benefiting more from training on an empty stomach than women.


Stannard, S.R., Buckley, A.J., Edge, J.A. and Thompson, M.W. (2010). Adaptations to skeletal muscle with endurance exercise training in the acutely fed versus overnight-fasted state. Journal of Science and Medicine in Sport, 13(4): 465-469.

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