Last year I saw a BBC docu-series called “E numbers: an edible adventure“, hosted by the adorkable Stefan Gates. Part of it dealt with MSG (mono-sodium glutamate) and how it’s a naturally occurring substance, an amino acid to be exact, used chiefly in our body to make protein. It’s especially prevalent in protein-rich foods, such as meat, fish, beans and especially parmasan cheese. In fact, Stefan goes so far as to suggested that when you add parmasan to your spaghetti you’re actually adding more MSG than you’d find in your average Chinese takeout.

So, that was my stance on the subject.  I know it affects some people badly, my mother for example, gets migraines if she consumes it, but I’ve never had that problem, so I was happy to eat it whenever I came across it.

That’s one fat rat!

That was until last night, when I learnt what scientists do rats to study obesity.  They induce obesity in  rats by injecting baby rats with MSG (one study I read was written in 1974, so we’ve known this for quite a while, apparently!)

For an eye opening experience, search MSG rats in Google Scholar

So how does MSG cause obesity? Well, it turns out it’s the G of MSG (glutamate) that’s the bad stuff. Firstly, it triggers your pleasure receptors making the food your shoveling into your gob the tastiest thing you’ve ever had! It’s like MDMA of the food world. It has been suggested that MSG can make dirt taste good (I’d be interested in putting that to the test, actually) thus leading us to the first part of the problem: overeating and potential food addiction.

The second part of the issue is that MSG triples your insulin response. When you eat something, your blood sugar levels rise as you absorb the food, your pancreas releases insulin to control the amount of sugar is your blood. It tries to keep the system balance. Glutamate causes your body to produce way more insulin than is required and so your blood sugar levels drop instead of going up, sending your body into starvation mode. You become hungry and, again, potentially overeat. So it’s true. You are hungry five minutes after eating Chinese takeout!

But wait, there’s more! Insulin increases the storage of fat in fat cells and prevents the cells from releasing it for energy. So you’re hit with a triple whammy. Two possibilities for overeating and finally storing away the fat instead of using it as energy. It’s no wonder obesity has reached epidemic proportions.

Now, while the MSG found naturally in some foods is identical to the additive version, the difference lies in the quantity. The best analogy I’ve heard is that natural MSG is like a glass of wine with 9% alcohol, while the additive is more like a same size glass of whiskey with 40% alcohol. So while you will experience the same effects eating natural MSG in foods you will consume a lot less of it than the MSG used as an additive.

So naturally, what with trying to loose weight and all, I’ll definitely be reading those pesky ingredient labels from now on.