The study involved 14 participants who were assigned at random to watch ether a stressful or a humorous video for 20 minutes. A week after the viewing the volunteers were shown the opposite genre video so reactions could be compared.
The team of researchers measured levels of two hormones in the blood of the volunteers known as leptin and ghrelin, both of which are linked to appetite.
The stressful videos had no clear effect on the hormones whereas the humorous videos cause a fall in leptin and a rise in gherlin, a similar effect is caused by physical exercise and is believed to stimulate appetite.
These findings could lead to the development of improved ways of encouraging healthy eating for patients who struggle to eat due to depression, chronic pain or other medical conditions which cause a loss of appetite.