Dr. Ka He of the University of North Carolina at Chapel Hill School of Public Health and colleagues studied more than 750 Chinese men and women, ages 40 to 59, in three rural villages in China. A majority of the study participants prepared their meals at home without commercially processed foods, but 82 percent used MSG in their food.
The researchers said they chose study participants in rural Chinese because they used very little commercially processed food, but many regularly used MSG in food preparation.
Those who used MSG were divided into three groups, based on the amount used.
The study, published in the journal Obesity, found the one-third who used the most MSG were nearly three times more likely to be overweight than non-users.
"We saw this risk even when we controlled for physical activity, total calorie intake and other possible explanations for the difference in body mass," He said in a statement. "The positive associations between MSG intake and overweight were consistent with data from animal studies."