Australasian Science: Australia's authority on science since 1938

Exercise First, Eat Later

By Stephen Luntz

The pain of early morning exercise may have a benefit for athletes, with evidence that those who train before breakfast get more benefit than those who eat first.

Conventional advice is that athletes should eat before training, but A/Prof Steve Stannard of Massey University is not surprised that his research found otherwise. “Training is all about putting the body under stress, not going faster,” Stannard says. “So by starting out with less fuel, you will reach the point where you really begin to stress the body quicker. This means you will spend longer under stress, and ultimately the training will be more beneficial.”

However, athletes should not get so used to training without food that they avoid eating before competition. “There is a large amount of evidence supporting carbohydrate ingestion before and during prolonged exercise to increase endurance performance. In essence, this means that eating some carbohydrate before competing will help you go faster for longer during a race,” says Stannard.

Stannard split cyclists into two groups, one of which had a high carbohydrate breakfast before training while the other ate later. Each group cycled for 75 minutes per day for 4 weeks. Blood samples and muscle biopsies from each group showed that those who trained before breakfast used oxygen more efficiently, had a greater increase in peak power and could store more muscle glycogen than their colleagues.

One interesting variation came in the capacity to burn fat. Here again, male cyclists benefited from training on an empty stomach but female riders showed the reverse effect. Fat-burning capacity boosts endurance performance, so the results suggest that training before eating might offer more mixed benefits for female competitors.

Stannard is wary, however, of concluding that women who want to lose weight rather than win medals should eat before exercising. “This was a small study, although a well-controlled one,” he cautions. “Someone needs to go out and do this again.”

Aside from imagining that sex hormones play a role, Stannard says he does not know why men and women should respond differently when it comes to fat-burning capacity when their results are similar on other tests.

Many people already choose to exercise before eating.

Stannard says this is partly because “most people can’t run on a full stomach”. However, he says “there is a dogma pushed by cereal companies that you need carbohydrates to sustain your exercise”.