MSG, the food additive that is often associated with migraines and found in preservative rich American foods and Asian cuisine, has been found to increase the waist line. A study conducted in China followed men and women around for 5 ½ years, and documented their MSG consumption. It found that those who ate the most MSG, around 5 grams per day, were 30% more likely than those who ate only half a gram per day to gain weight.
MSG is the most highly used food additive in the world, and though American’s do not consume as much as those in Asian countries, the Chinese population is more active than American society, therefore obesity is not as prevalent. Ka He, a nutrition expert at the University of North Carolina, believes that the link between MSG and weight gain is due to a hormone called leptin, which regulates appetite and metabolism. He told Reuters, "MSG consumption may cause leptin resistance," which would make it difficult for the body to properly process the energy it receives from food with MSG. Ka He hopes to follow up this study with a study tracking the health benefits of stopping MSG intake.