The time it takes for food to pass through the gut. This is not only of academic interest as it can have important consequences for health and comfort. If food passes too quickly through the gut, there is little time for it to be digested and nutrients will be lost in the faeces. If food is retained for a long time, constipation may result and faeces become hard and bullet-like. In addition, the longer food remains in the gut, the more calories can be absorbed: efficient in biological terms, but not what someone on a weight-loss diet wants.
Food rich in fibre tends to normalize the food transit time of those whose food either passes through the gut too quickly or too slowly. High fat levels in the diet tend to delay the passage of food and may contribute to constipation. Exercise stimulates peristalsis (the movements of the muscular wall which pushes food along the gut). This is a possible cause of ‘jogger's trots’, the urgent need for early-morning joggers to find a lavatory or some other place to relieve themselves. The quicker passage of food through the gut associated with regular physical activity may also offer some protection against cancers of the colon and rectum.
Subjects: Medicine and Health.