A report, published in Obesity, that tracked the food habits and weight of inhabitants of three villages in China, has found a link between the use of monosodium glutamate (MSG) in foods and obesity in adults. The research was undertaken in areas of the country in which most people rarely use commercially processed food, but in which about 80% add MSG to their cooking. After controlling (for BMI, smoking, physical activity etc.), the researchers found that the third of people who use the most MSG were nearly three times as likely as those who used no MSG to be overweight (BMI>25).
It is unclear what is the reason for the association as, although MSG makes food taste better (which could lead people to eat more), the research controlled for total energy intake. The study has established the association, but not a causal relationship.
Source: New York Times, 25 August 2008.