Consumption of monosodium glutamate, or MSG, the widely used food additive, may increase the likelihood of being overweight, a new study says.

Researchers studied 752 men and women in three villages in northern and southern China where most people use little commercially processed food, but where about 80 percent of people add MSG in cooking.

After controlling for body mass index, smoking, physical activity and almost two dozen measures of daily nutrient intake, they found that the one-third of people who used the most MSG were almost three times as likely to be overweight — that is, to have a body mass index over 25 — as those who used none. On average, with each 0.04-ounce daily increase in MSG intake, B.M.I. went up by 0.61.

 

MSG makes food taste better, which may lead people to eat more, but the researchers controlled for total energy intake so it is unlikely that that explains the finding. The mechanism for the connection, published in the August issue of Obesity, remains unclear.

Dr. Ka He, the lead author and an assistant professor of epidemiology and nutrition at the University of North Carolina, said the study established an association, not a causal relationship.

“MSG is not toxic,” he said. “But now the question is: Is it healthy? This study is a warning that we should be cautious.”