THE SCIENCE BEHIND
NOZNOZ™

The role of olfaction in regulating appetite, food intake, and body weight has been studied extensively, but is so complex that we have only begun to understand this system. Exposure to food odors increases food intake and loss of smell reduces food intake. Overweight and obese humans and animals tend to have a reduced sense of smell compared to lean individuals, however, obese individuals exposed to pleasant smelling food odors eat more of a test meal than do lean individuals (2,3) and restrained eaters eat more when exposed to food odors (4,5). Both lean and overweight individuals had an increased hunger rating after seeing and smelling pizza for 60 seconds, but overweight individuals had increased salivation and an increased desire to eat both pizza and other tasty foods as compared to lean (6).

There are few data on the effects of reduced smell on food intake and weight, and almost all studies have been in animals. Riera (1) knocked out olfactory neurons mice, resulting in decreased smell. They noted a slight decrease in food intake on regular healthy chow, but a larger decrease on high fat diet. They found a significant reduction in body weight and fat mass with no change in lean mass and a significant increase in energy expenditure (1).