Australasian Science: Australia's authority on science since 1938

Stomach Responds to Time of Day

By Stephen Luntz

Nerves in the stomach alter the amount we can eat without feeling full depending on the time of day.

The discovery, published in The Journal of Neuroscience, may shed light on why shift work is often associated with weight gain, although at first sight the findings suggest that the opposite should be the case.

Dr Stephen Kentish of the Adelaide University Nerve-Gut Research Laboratory collected stomach tissue and cultured it. Every 3 hours the tissue was stretched and the response of the nerves examined. “These nerves are responsible for letting the brain know how much food we have eaten and when to stop eating,” says Kentish.

During the day the nerves showed lower sensitivity than at night. “This means more food can be consumed before we feel full at times of high activity, when more energy is required,” says Kentish.

“People who are just beginning shift work and have little experience of it will report an inability to consume whole meals (and) feelings of nausea,” says Kentish. This might be expected to lead to weight loss. However, over longer time periods shift work is associated with increased body mass, which Kentish thinks may be associated with disrupted signals and an inability to match energy intake and usage.

“I’m not sure that there is advice on how to lose weight from this work,” says Kentish, “but without overstating these results they suggest there are mechanisms that are trying to ensure food intake is constrained to when we are most active, so it is probably advisable to avoid midnight snacking.”