Does MSG Promote Obesity?

Recent headlines about a study done in China on 752 healthy adults reported that those who consumed the most MSG were about twice as likely to be overweight as those who ate none.1 However, a much larger study done earlier in Hawaii, which examined about 5,000 users and nonusers of MSG found no evidence the regular use of MSG had any impact on body weight.

Certainly the Chinese study shows a weak correlation between using more MSG and having a higher BMI. However, correlation does not equal causation. Indeed, the author?s own data (Table 1.) shows the percent of glutamic acid consumed in the 4 groups was virtually the same. Why was there no significant association between the amount of MSG added to their food and the percentage of the calories coming from glutamic acid? Their typical diets contained more than 10,000mg of glutamic acid as part of the diet's protein. By contrast, the average MSG user in this study consumed only about 330 mg of MSG per day. Note also that higher MSG use was associated with a diet higher in % fat, animal protein, and lower in fiber. Finally a greater use of MSG was correlated with a higher calorie intake. Is it not more likely that eating a diet lower in fiber but higher in fat, meat and calories was more likely the cause of the greater BMIs than a little extra glutamate from MSG?By James J. Kenney, PhD, RD, FACN1. Obesity 2008;16:1875-802. Hawaii Med J. 1973;32:13-7

Table 1. Adjusted Characteristics of the 752 Chinese Adults
by MSG Intake
Characteristic	Non-MSG Users	Tertile #1	Tertile #2	Tertile#3
BMI	22.3	22.7	23.1	23.5
Glutamate (%kcal)	2.9	2.9	2.9	3.0
Animal Protein (%kcal)	1.9	2.3	2.7	3.1
Total Fat (% Kcal)	17.2	18.8	20.4	22.4
Fiber (g/1000 Kcal)	16.0	14.1	13.6	13.5
Calories (Kcal)	1,965	1,961	2,031	2,216