Larry's Experiment, Does MSG Cause Obesity?

The background on obesity

Over the last few decades, obesity has become a huge health problem in the USA, the UK, and some other developed countries. Many health writers even use the word epidemic to describe it. Obesity is a risk factor for breast cancer, for Type 2 diabetes, for cardiovascular diseases, and for osteoarthritis.

Here's a refreshing contrast with the depressing news about the dangers of frank obesity: Research at the University of Western Australia suggests that for elderly people, being moderately overweight is not a health risk.
Overweight elderly 'live longer'

The reasons for the obesity trend are not well understood. It's tempting to chalk up our dismal obesity statistics to lack of exercise. Daily strength training for my upper leg muscles has decreased my big appetite somewhat. Although I'm a senior by some measures, I'm slightly less corpulent than I was at age 20.

However lack of exercise is a partial answer. There is much speculation about the other causes of the obesity trend. The High-Fructose Corn Syrup used to sweeten soft drinks in the USA is another proposed villain. There may be a single 'control variable'--like HFCS--which accounts for most of the obesity statistics. Or there may be multiple issues, which taken together, add up to the big problem.

It's predictable that some would blame Mickey D and 'super-sizing' for the obesity trend. Hub author alexadry analyzes the Fast-food Conjecture about obesity from a common-sense perspective.

However occasional fast food does taste good. That's partly because fast-food restaurants pull out all of the stops on seasonings and on flavor-enhancement, as do Chinese restaurants. MSG (monosodium glutamate) is an almost ubiquitous flavoring in both types of food. Does the MSG nudge us into overeating, as some claim? We'll investigate that question in the next section.

And while we're on the subject, why is obesity relatively uncommon in Japan, whose cuisine contains MSG?


Even though it's not listed as an ingredient on the label, soy sauce contains glutamate.
Even though it's not listed as an ingredient on the label, soy sauce contains glutamate. | Source
Mad scientist Larry
Mad scientist Larry | Source

My MSG experiment

Lets explore the question about the putative MSG-obesity connection. I'm aware of many of my 'trigger foods', and I don't feel comfortable keeping some of them in the house. It's very possible that MSG is a 'trigger seasoning' for some people. In late 2011, I decided to do a scientific experiment to test that hypothesis on my favorite guinea pig, myself.

Unfortunately, I did not have any MSG on the spice shelf. And being a cheapskate, I didn't want to buy a bottle of the stuff, and then let it gather dust on my spice shelf for the next 20 years after the experiment. I substituted Sichuan hot sauce. Two items from the list of ingredients were dead giveaways: soy sauce and hydrolyzed vegetable protein. Each of these contains glutamate.

I sipped an entire 11-ounce bottle of the Sichuan sauce, which someone had given me as a housewarming present many years ago. I needed two sessions, because the stuff is really hot! However I can handle spicy-hot seasonings that would cause hair to grow on the feet of lesser mortals.

I did notice two specific cravings. First, for more Sichuan hot sauce. And second, for water! Surprisingly, there were no cravings for carbohydrate-rich food, or for fat-rich food. However if I'd been eating barbecued ribs covered with this sauce, I definitely would have pigged out. If I'd been eating salad instead of ribs, and had substituted Sichuan sauce for the salad dressing, the outcome would have been similar, but with fewer calories in the balance.

One puzzling aspect of the experiment was the capsicum flavor in the sauce. Ordinarily, cayenne is an appetite stimulant for me. That's why I don't use this seasoning very often. The hot sauce should have stimulated my craving for carbs, but it did not.

The take-home lesson from my experiment is that we have multiple food-related cravings. If we want maximum satisfaction from a meal with a minimum number of calories, we need to satisfy as many of those cravings as possible. Going back for seconds on that tuna casserole is not the best strategy for moderate eating when we've already satisfied our carb jones with the first helping, and the only thing we crave is more protein. Self-awareness is more valuable than any of the bogus, one-size-fits-all diet plans promoted by the weight-loss industry.

There are two obvious caveats to my little study. First, an experiment having a sample size of one does not lend itself to sweeping generalizations that apply to most people.

Second, my El Cheapo experiment could have been more elegant. There were other ingredients in the Sichuan hot sauce in addition to glutamate: sherry wine, sesame oil, capsicum and ginger, to name a few.


Monosodium glutamate
Monosodium glutamate | Source

Some serious science on MSG

The Japanese recognize umami (glutamate) as a distinct fifth taste, in addition to the classic tastes: bitter, salty, sour, and sweet. Our sense of smell contributes the remainder of the taste perception of the food that we eat. For a fun experiment, pinch your nose while you eat some yummy food. Much of the tastiness will disappear.

When MSG dissolves in water, it tends to dissociate into positively charged sodium ions and negatively charged glutamate ions. See diagram. The negatively-charged glutamate ion, rather than the positively-charged sodium ion, is the bone of contention.

The bad news is that extremely high levels of glutamate in the brain (where it normally acts as a neurotransmitter) are excitotoxic, and can accelerate the progression of Parkinson's Disease.

The good news is that dietary glutamate does not pass the blood-brain barrier in normal, healthy people. Thus dietary glutamate is not a neurotoxin.

Yes, some individuals do get headaches when they eat too much MSG in their food. At one time, this phenomenon was called Chinese Restaurant Syndrome, for obvious reasons.

Surprise, surprise! MSG is not necessarily benign for all people, in all quantities, at all times, and under all circumstances.

Even if you follow a 100% organic, politically correct, vegan diet, it is not possible to avoid glutamate entirely. Why not?

When you digest protein of any kind--of animal or plant origin--glutamic acid is liberated from the larger parent molecule. For example, wheat gluten is 30% glutamic acid. When dissolved in water, glutamic acid dissociates into positively charged hydrogen ions and negatively charged glutamate ions.

The upshot: Whenever you eat an ordinary meal--organic, vegan or otherwise--you're getting glutamate ions, the equivalent of MSG. If you want to follow a simon pure diet that contains zero glutamate, then you'll need to avoid all protein--even the relatively small concentrations found in rice, corn and potatoes. Unfortunately, total long-term protein avoidance will kill you.

The real MSG (glutamate) issue is about quantity. Here's an old saying from Paracelsus:

"The dose makes the poison."

I've explored that theme in an earlier hub:
The Scare-of-the-Month Club and Evil Chemicals

At the moment, scientific research on a putative MSG-obesity connection is a mixed bag. Here's a recent scientific literature reference, which concluded that MSG use is not associated in a measurable way with obesity in humans.

Shi, Z; Luscombe-Marsh, ND; Wittert, GA; Yuan, B; Dai, Y; Pan, X; Taylor, AW (2010). "Monosodium glutamate is not associated with obesity or a greater prevalence of weight gain over 5 years: Findings from the Jiangsu Nutrition Study of Chinese adults". The British journal of nutrition 104 (3): 457?63. doi:10.1017/S0007114510000760. PMID 20370941

Of course, this study is not a conversation-stopper. When more information from the scientific community rolls in, we'll have a better picture of the risks (and possible benefits) of glutamate.

If you want to be healthier and perhaps a bit leaner, the most important advice I can offer is for you to emphasize the important stuff, about which we already know, rather than wasting your precious time on wild speculations about 'evil' chemicals, whose obesity promoting effects--if any--are still too small to measure. If you don't already have a regular exercise routine, I encourage you to craft one that's comfortable and sustainable for you. Here's a link to my earlier hub about how to
tweak your aerobic exercise routine.


Addendum: Analysis of Paul Lam's anti-MSG article

MSG: More Than Meets the Tongue

The factual content of Paul's article is considerably less than meets the eye. However it's fairly representative of the Scare-of-the-Month-Club online twaddle about 'evil' chemical hobgoblins hiding under our metaphorical beds.

I thank Rasta1 for bringing it to my attention, and for helping me to make this a better hub. Otherwise I would have let sleeping dogs lie, lest discerning readers suspect that I had cherry-picked a monumentally stupid anti-MSG diatribe, in order to make a Straw Man Argument.

Paul claims:
"The MSG manufacturers argue that processed MSG is a pure salt exactly the same as the glutamate in our bodies, whereas, the MSG antagonists argue that processed MSG is impure and also contains a different isomerism, a mirror image of glutamate from the ones naturally made in our bodies."

Larry's comment:
In Nature, all glutamate is left-handed. Transforming all of the natural glutamate in soy protein or in wheat gluten into the right-handed isomer would be pointless and extremely expensive.


Paul claims:
"MSG has various detrimental effects, which include triggering asthma attacks and exacerbating migraine headaches."

Larry's comment:
Paul's sentence is misleading. In the case of nutrients, including nonessential amino acids like glutamate, Paracelsus centuries-old maxim applies. I already mentioned it in an earlier section of this hub, but it's worth repeating.

"The dose makes the poison."

Using the Paul's logic, I could claim that water is 'bad for you'.

*sarcasm on* Here's a thought experiment. Paul parachutes into the middle of Lake Superior, wearing only a Speedo, with no gear whatsoever, just after all of the Winter ice has melted. Conclusion: Water causes hypothermia and drowning. Water is bad, bad, bad. We need a zero-tolerance policy for water. And that includes drinking the vile stuff, and eating any food that contains water. *sarcasm off*

A priori, extremely high doses of glutamate--especially on an empty stomach--have unpleasant effects. But Paul isn't smart enough to see the need for that caveat in his little horror fantasy.


Paul claims:
"Excess glutamate, acting as an excitatory neurotransmitter, causes over stimulation in the brain prolonging the migraine attacks."

Larry's comment:
Paul has neglected to mention the pesky fact that dietary glutamate does not pass the blood-brain barrier in normal healthy adults. Yes, overdosing on MSG can cause headaches. I know, because I had an MSG headache from too much soy sauce many years ago. The mechanism that Paul suggests does not apply to headaches.


Paul claims:
"In more serious cases, MSG may even cause neuronal death due to over stimulation."

Larry's comment:
Yes, extremely high concentrations of glutamate in the brain can be excitotoxic. So what? Again, we need to take the blood-brain barrier into account.


Paul claims:
"Metabolizing glutamate after a MSG-rich meal induces the release of glucose into the blood stream. This in turn triggers the secretion of insulin by the pancreatic islet cells, so that muscle cells can take up glucose. Obesity is characterized, in part, by high levels of plasma glucose and insulin. Studies have shown that mice injected with MSG became obese and eventually lead to insulin-resistance and the onset of Type 2 diabetes."

Larry's comment:
Suppose that we eat more protein than we need. (Proteins are amino acid polymers.) The body can use the excess amino acids as starting materials to make glucose, which it uses for fuel. This process is called gluconeogenesis. When our our blood sugar is low and our glycogen stores are depleted, gluconeogenesis of amino acids from our muscle tissue can also generate much-needed glucose.

For normal healthy people, the insulin released by the beta cells is proportional to the blood sugar concentration. However extremely high oral doses of MSG on an empty stomach can trigger an insulin response in humans. Is this insulin response out of proportion to the amount of gluconeogenesis going on?

If so, the increased insulin levels could depress blood sugar levels, thereby increasing carb cravings. Yes, it's theoretically possible that huge excesses of MSG could be a carb-craving 'trigger' for some moderately overweight people. And yes, I know about carb-craving triggers, because I have some. The above experiment has demonstrated that MSG is not one of mine.

There's another question here. Ordinarily, MSG is consumed with food. How relevant are studies in which large doses of MSG are taken on an empty-stomach? *drumroll* Again, the dose makes the poison.

As I pointed out in an earlier section, the jury is still out on whether or not free glutamate--with food, and in the quantities ordinarily consumed by humans--contributes in a measurable way to obesity in people. Taken as a whole, the studies are inconclusive at this point. It's dishonest to trot out such-and-such a study, and then to claim that this 'proves' the 'evilness' of the MSG Monster.


Paul claims:
"Moreover, MSG has been shown to stimulate appetite in humans. Subjects that had MSG-rich meals exhibited more stimulation to eat and ate more often than control subjects."

Larry's comment:
Although I'm not familiar with this particular study, I'll try to put it into perspective.

In the bad old days, being obese was less harmful than in developed countries in the 21st Century. Why? First, you were likely to be killed by tuberculosis or some other infectious disease, before you had a chance to become diabetic, and before you were felled by a heart attack.

Second, the food supply was less predictable. Being fat was a form of insurance against famine.

Being fat was also insurance against major infectious diseases, which were more common in the bad old days. When I was a child, I came down with meningitis. It took many weeks to shake off the disease. By the time I was well enough to resume a normal life, I'd lost a lot of weight. My upper legs were so weak that they were wobbly after walking up a small hill on the way to school. If I'd been underweight at the beginning of the illness, it's possible that I would not have survived.

Fourth, in the bad old days, women encouraged their families to eat. One indirect way to accomplish this objective was to cook great-tasting food, with optimal amounts of flavorings, seasonings, and spices.

Does the use of basil in Italian cooking promote frank obesity? In terms of appetite enhancement, are MSG and basil fundamentally different?

In the Experiment section of this hub, I noted that the glutamate-containing Sichuan sauce created a very specific craving for more of the same. It did not affect my appetite in any other way. I think that a part of obesity stems from a relative inability to sort out the various types of hunger signals.


Paul claims:
"Many manufacturers rename the monosodium glutamate ingredient to euphemistic terms such as, malt extract, corn syrup, cornstarch, or hydrolyzed “anything”.

Larry's comment:
Although corn syrup does not contain monosodium glutamate, there may be trace amounts of free glutamate. Early steps in the manufacturing processes remove most--but not all--of the corn protein. It's very possible that a later step could inadvertently break down part of the remaining corn protein into its component amino acids.

One nice thing about my academic specialty, analytical chemistry, is that we can easily measure ppm concentrations of the stuff, if it's really there. Are tiny amounts of free glutamate in cornstarch and corn syrup cause for concern? Not particularly.

However some people are highly allergic to corn protein, and to some corn protein peptides (fragments of the parent protein molecules). If you have a severe corn allergy, please check with your physician before eating cornstarch or corn syrup. Ditto for restaurant foods and convenience foods that contain these ingredients.


Conclusion for the Addendum section:
I am not saying that MSG is wonderful, nor am I saying that it's risk-free. In fact, I'm not saying that anything is 100% risk-free. However I do have some free advice for stealth Luddites who aspire to be taken seriously as health writers by scientifically literate people: Grow up!


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Comments 18 comments

rasta1 profile image

rasta1 4 years ago from Jamaica

Thanks for the little experiment, MSG is also an endocrine disruptor, it causes cells to become greedy.


Larry Fields profile image

Larry Fields 4 years ago from Northern California Author

Hi rasta1. Thanks for stopping by.

By the way, can you cite a reference in a peer-reviewed scientific journal to back up your claim? To the best of my knowledge, the glutamate moiety is found in all food proteins commonly eaten by people. If MSG is an endocrine disruptor, then so are meats, poultry, fish, eggs, milk, cheese, legumes, grains, potatoes, nuts, and hemp seeds.


WillStarr profile image

WillStarr 4 years ago from Phoenix, Arizona

My weight seems to have varied inversely with my testosterone level. That’s my excuse!


Larry Fields profile image

Larry Fields 4 years ago from Northern California Author

Hi Will. Thanks for your observation.

Some dieters claim that the last 10 pounds are the toughest. But there's another perspective on the same reality.

I enjoy my quickie exercise routine. And for a senior, my body fat is within the healthful range. I'm not willing to make myself miserable in order to look like a movie star.


rasta1 profile image

rasta1 4 years ago from Jamaica

Meats in excess (everyday) are also endocrine disruptors especially if it is genetically modified and/or also fed hormones. One of the reasons bodybuilders use glutamine is to get bigger. This amino acid is a main cell food.

Apart from the fact that MSG also causes more food intake, it also leads to more salt intake, therefore more water intake. It causes glucose to be released in the blood which triggers the release of insulin, which then stores the glucose as fat or burns it.

http://www.scq.ubc.ca/msg-more-than-meets-the-tong...

http://www.ncbi.nlm.nih.gov/pubmed/7413022


Larry Fields profile image

Larry Fields 4 years ago from Northern California Author

Rasta1, thanks for the first link. Time permitting, I'll write an addendum to address some of the errors in that article.

By the way, you're conflating glutamic acid (the source of the glutamate cation) and glutamine. They are two different amino acids.


rasta1 profile image

rasta1 4 years ago from Jamaica

glutamic acid and glutamine are interconvertable. they make each other. One has an amide group chain and the other hydroxyl group chain. These groups are easily interconvertable from one to the other.

Looking forward to your next article. Peace


Larry Fields profile image

Larry Fields 4 years ago from Northern California Author

Rasta1, I've also experimented with glutamine supplements. For me, they decrease my carb cravings somewhat. This is the exact opposite of what glutamic acid is supposed to do.


Robertr04 4 years ago from Detroit,Mi.

"The dose makes the poison." Scientists believe that "the dose" or the amount you take is what makes a chemical poison to you. The long-term, the low dose affects of chemicals like msg have not been tested. Scientists operate under the assumption that when a dose is low enough to not cause an effect that there is no need to test lower doses. In fact , the term "low dose is misleading, and intends to imply that low doses or lower concentrations of a chemical are not harmful. The lowest levels tested generally with no affects are used as the basis to establish safe standards of exposures for people. Most chemical safety policies follow this premise. But new research is demonstrating that smaller amounts of chemical toxins overtime can cause greater affects than larger amounts. Therefore, harm can occur at much lower doses than previousy believed, because smaller amounts can accumulate in the body and overtime cause severe health problems.


Larry Fields profile image

Larry Fields 4 years ago from Northern California Author

Hi Robertr04. Thanks for stopping by. Apparently you did not notice this part of my hub:

"Even if you follow a 100% organic, politically correct, vegan diet, it is not possible to avoid glutamate entirely. Why not?

"When you digest protein of any kind--of animal or plant origin--glutamic acid is liberated from the larger parent molecule. For example, wheat gluten is 30% glutamic acid. When dissolved in water, glutamic acid dissociates into positively charged hydrogen ions and negatively charged glutamate ions.

"The upshot: Whenever you eat an ordinary meal--organic, vegan or otherwise--you're getting glutamate ions, the equivalent of MSG. If you want to follow a simon pure diet that contains zero glutamate, then you'll need to avoid all protein--even the relatively small concentrations found in rice, corn and potatoes. Unfortunately, total long-term protein avoidance will kill you.

"The real MSG (glutamate) issue is about quantity."

That was the context for my use of the famous Paracelsus quote. It's important for non-scientists to understand that glutamate is a non-essential nutrient, rather than a xenobiotic. The relative safety of glutamate is NOT a qualitative issue.


Robertr04 4 years ago from Detroit,Mi.

Ha,Ha. Ok Larry, spoken like a true scientist. We'll be talking again I'm sure.


Illumind profile image

Illumind 4 years ago from Infinity

Very informative. I've been "waking up" to a lot of lesser-known truths in recent times, and have become a bit of a freaked-out conspiracist. Before reading this I had the view that MSG and aspartame are simply excitotoxins that always cause or promote neurodegenerative diseases like ALS and therefore should be avoided at all costs. Now I am beginning to see there is more to it. Thanks for the enlightenment. I'll have to bookmark and share this one.


Illumind profile image

Illumind 4 years ago from Infinity

If some people are sensitive to MSG, then they should be sensitive to eating too much protein, too, right? So what causes glutamate sensitivity? How do we address that so they can eat protein and MSG without excitoxicity?


Larry Fields profile image

Larry Fields 4 years ago from Northern California Author

Dean, thanks for stopping by.

About the glautamate-protein connection. First, it is possible to eat too much protein. As is the case with all other essential nutrients, there's an optimal amount for health for any given individual.

If I remember correctly, humongous amounts of protein can contribute to hypothyroidism for people whose thyroid function is marginal to begin with. Ditto for people whose consumption of the B-vitamin, folic acid (leafy greens, oranges, legumes) is marginal.

Fortunately for us, dietary glutamate does not penetrate the blood-brain barrier in healthy adults. And excitotoxity of brain cells is probably not an issue for dietary glutamate.

Nevertheless 'Chinese Restaurant Syndrome' is still a possibility for some people, including me at one point in my life. Does CRS shorten lifespan to a measurable extent? I don't know. It'd probably be difficult to measure.

Is protein-bound glutamate quantitatively equivalent to the free glutamate in MSG or soy sauce? No, it's not. We can think of protein as being a time-release source of glutamate, because protein digestion is much slower than free glutamate absorption.

The upshot: You're much less likely to get a CRS headache from x grams of glutamate in dietary protein, as compared with x grams of free glutamate from MSG or soy sauce.


Hally Z. profile image

Hally Z. 4 years ago from Madison, Wisconsin

Actually, glutamate is able to target the hypothalamus, which is also the most sensitive to glutamate, because the hypothalamus has almost no intact blood-brain barrier. This has also been shown in newborn mice who were fed MSG; their hypothalamic regions were destroyed. The main danger of MSG is that it is an excitotoxin and releases free glutamate upon being dissolved. Glutamate is of course found in other foods like tomatoes and parmesan cheese; however, it's not that bad there because it must be digested first before being released; i.e., it isn't free. As an example I list myself; I don't get migraines from pasta sauce and cheeses or bread containing gluten, but I most definitely get migraines from soy sauce and anything coated with MSG.


Larry Fields profile image

Larry Fields 4 years ago from Northern California Author

Hi Hally Z. Thanks for stopping by. And thanks for pointing out the chink in the armor of the blood-brain barrier. You also wrote:

"The main danger of MSG is that it is an excitotoxin and releases free glutamate upon being dissolved."

As General Semantics buffs would say, there's a small problem with the word "is" in the above sentence, because glutamate "is" also a neurotransmitter. We'd all be dead if our brains could not synthesize it from other amino acids.

Paracelsus famous maxim definitely applies here. It'd be more accurate to say: An excessively high concentration of glutamate in the brain can have an excitotoxic effect. At the moment, we don't know the threshold concentration for excitotoxicity.

I also get migraines from time to time. Interestingly, I did not get a migraine from my little MSG experiment. This suggests that there's more to migraines than an excitotoxin concentration above a certain line-in-the-sand, threshold level.


ChristyWrites profile image

ChristyWrites 4 years ago from British Columbia, Canada

Thanks for all of the information about MSG. I recently had chinese food and now I am more conscious of what exactly is MSG.. good to know!


Larry Fields profile image

Larry Fields 4 years ago from Northern California Author

Hi ChristyWrites. Thanks for stopping by.

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