JACKSON, Mississippi - MSG has been a public buzzword since it was taken out of baby foods in the late 60s.
But most people don't know that it's in literally thousands of different processed foods, often under hidden names.
And now, science is showing us that it could be a big part of what's making us so fat.
Think you're not eating MSG? Many foods at Pizza Hut, Taco Bell, and McDonald's have it.
Wonder what the Colonel's secret ingredient was? MSG.
Oh, you don't eat fast food? Even classy restaurants throw in some.
Oh, you don't eat out? Sorry, your grocery is loaded with MSG too, and school cafeterias are just as loaded.
Well, at least your baby's safe. Guess again, almost all infant formulas are packed with it.
Dr. Russell Blaylock has studied these common flavor enhancers that many experts believe are hazardous to your health. He calls them Excitotoxins: The Taste that Kills. And he says you're more exposed to them than you realize.
"One of the misconceptions is that -- 'Well, I don't eat Chinese food, so I'm not really exposed to MSG,'" Blaylock said. "Well, if you look at almost all processed foods, the vast majority of them have one or more forms of this high glutamate content in it."
Since the 1950s, the Food and Drug Administration has considered MSG to be safe and the agency has not changed that position despite a large volume of research -- especially in the last 10 years.
In other words, the government currently has no restrictions or warnings on MSG.
Yet, numerous scientists from around the world have repeatedly confirmed that glutamate in the diet can cause a range of problems in animals -- including obesity.
But those who say MSG is safe argue that people don't consume as much MSG as animals are given in experiments. So they say people don't face glutamate damage.
Blaylock says that's not so.
"These foods, particularly in a child, are certainly of a dose equal to what you're seeing in animals. Now the thing that's peculiar about the child -- they're four times more sensitive than an adult, pound for pound."
And adults themselves are about five times more sensitive than the most glutamate-sensitive creature -- the mouse.
What that means is when people consume MSG, their blood levels of glutamate rise much higher and stay in the blood much longer than any other creature. The result is that humans are more easily exposed to toxic levels of glutamate.
And babies in the womb and young children up to age three are the most threatened. That means expectant mothers may need to be mindful of their diets. And when the babies are born, moms may want to watch out for what's in their formula.
Nearly all formulas contain high levels of highly processed milk and soy protein. The processing breaks down those two proteins, releasing high levels of glutamate and aspartate. Both are excitotoxins.
An unprotected part of the brain can then be damaged. That damage can permanently damage the body's ability to control obesity.
As children grow up, they do become less susceptible to MSG damage, but still very vulnerable to an obesity that is hard to get rid of.
Ultimately, the science indicates that all ages -- in varying degrees -- can face this type of hard-core obesity.
So is the public getting enough MSG in their food to trigger obesity at all ages? Estimates for MSG production and consumption vary widely, but almost everyone acknowledges significant and steady increases in the diet since 1960.
And that may relate directly to government figures on excess pounds.
Over the last 40 years, the government says adult obesity has jumped from 13 percent to 34 percent. And the number of overweight youth has quadrupled to almost 20 percent , with a steady rise for 40 years.
Of course, that doesn't necessarily prove the MSG has caused the increased obesity.
But Dr. John Olney, a pioneer in brain research, first found MSG caused obesity in lab animals in the 1960s. Olney wonders why no one was listening.
Olney even coined the term that describes this whole category of substances like MSG, aspartame and other glutamates - "excitotoxins."
And Blaylock says that the MSG theory makes much more sense than other causes, such as lack of exercise.
"The other curious thing about exposing animals to MSG early in life is that they prefer sweet foods, foods with sugar in it, carbohydrate foods, and they stay away from the foods that are healthier," Blaylock explained.
One of the frightening effects of MSG is that it preferentially produces visceral fat. That's the harmful fat found deep in the abdomen.
"And we know that people who have a lot of visceral-type fat have an extremely high incidence of heart attack and stroke, and arteriosclerosis," Blaylock noted. "They suffer from insomnia; they're more likely to have hypertension; they're more likely to have Type 2 diabetes, metabolic syndrome, and elevated LDL cholesterol."
Blaylock says that consumers will have to pick foods not solely on taste.
"Because there's intense competition between the food companies for taste," he said, "and for customers -- and customers choose foods based on taste, mostly. So if you can add a lot of this taste - flavor-enhancing MSG, you produce this effect."
And Blaylock believes that the effects on America could be wide ranging -- from making us less competitive in world sports to the more important impact of being less mentally capable in the international economy.
With obesity continuing to rise, ignoring the MSG component could mean there's no end in sight for the ravages of excess pounds.