In "Gulp", Mary Roach provides colourful insights on the human digestive system. Despite receiving wide praise I felt this book didn't live up to the high bar set by earlier book, "Stiff", although it was still a worthy read. Below are a few facts salvaged whilst reading:
- 80-90% of the sensory experience of eating comes from a person's sense of smell (olfaction).
- Humans have taste receptor cells in the gut but they are not linked to the brain. They are thought to trigger hormonal responses to molecules like salt and sugar, and defensive responses (e.g. vomiting) to dangerous molecules.
- The stomach is continually digesting itself as peptin and gastric acid break down the protective layer, but it is rebuilt fast and we have a new stomach lining every three days. As soon as we die, however, the digestion continues but the rebuilding stops. This leads to liquifaction of the interior, which Roach discusses in detail in 'Stiff'.
- In a study to find out to the extent to which the disgust response is taught versus being innate, psychologist Paul Rozin found that of children aged between 16-29 months, the following ate or tasted the following: fish eggs (60%), dish soap (79%), biscuits topped with ketchup (94%), a dead grasshopper (30%), coiled peanut butter scented with cheese and presented as dog poo (55%) and human hair (15%).