A recent study conducted by the University of Carolina at Chapel Hill confirmed what animal studies have hinted at for years: MSG (aka monosodium glutamate) could be a factor in weight gain.
The study focused on 750 Chinese men and women, ages 40−59, living in 3 rural villages in north and south China. Most of the study subjects prepared their meals at home without commercially processed foods and roughly 82 percent used MSG. Those participants who used the highest amounts of MSG had nearly 3 times the incidence of being overweight as those who did not use MSG, even when physical activity, total caloric intake, and other possible explanations for body mass differences were accounted for. The positive correlation between MSG and higher weight confirmed what animal studies have been suggesting for years.
Maybe you're wondering what MSG is and how you can eliminate it in from your diet. MSG is a flavor enhancer in foods—some believe it may even provide a fifth basic taste sensation (in addition to sweet, sour, salty, and bitter). It is what the Japanese call "umami" (roughly translated as "tastiness"). MSG is considered an "excitotoxin," since its role is to excite neurotransmitters (important brain chemicals), causing nerve cells to discharge and also exciting nerves related to taste. Perhaps the ability to excite these nerves is a factor in the association between increased MSG usage and weight gain.
How prevalent is MSG in the U.S. diet? Americans consumed about 1 million pounds of MSG in 1950, and today that number has increased by a factor of 300!
The Food and Drug Administration (FDA) describes MSG as "naturally occurring," and has it on the GRAS ("generally regarded as safe") list. However, in addition to its correlation to weight gain, some studies also reveal that as many as 25 to 30 percent of Americans have adverse reactions to it (e.g., palpitations and migraine headaches). As many as 30 percent, who consume more than 5 grams at one sitting, can have a more severe allergic reaction or suffer from gastrointestinal distress.
OK, if you're an MSG user who could stand to lose a little weight (or know someone who is), what should you do? Unfortunately, eliminating MSG from the diet is easier said than done. Given the fact that food manufacturers often change recipes, there is no "safe" food list and current labeling laws do not require one. A good start is to avoid anything with MSG in the ingredient list. However, there may still be foods that have MSG hidden inside other ingredients. Likewise, even products labeled "no MSG added" can still contain these hidden sources.
The safest and surest way to eliminate MSG from your diet is to consume whole fresh food, e.g. whole potatoes or French fries you make yourself from whole potatoes instead of a prepared frozen package or homemade soup instead of something from a can. While this can be time consuming and can represent a shift in your approach to eating, if you can adhere to this diet for a specified period of time, you might be able to discern how MSG is affecting your health. If you feel better and lose weight after this prescribed period of time, it might be that MSG was partly responsible for your compromised health. Of course, the positive benefits could also be attributed to your adherence to a whole food diet.