MSG, Trans Fat, and Aspartame: 3 Secret Ingredients That Are Killing You and Your Results

You’ve probably heard food additives are bad for you but it’s hard to avoid them. A new study examined how MSG, trans fat, and aspartame impact health.

Most of the readers of Breaking Muscle are concerned about health and actively do something about it. There is perhaps no single better way to stay healthy than a good diet. While this is common sense, the number of athletes and trainees I work with who have pretty poor diets is surprising. I wish I could say that I’m exempt from that myself, but eating poorly happens to the best of us.

One way I’ve found to dissuade eating foods that will mess with your results and put you in bad health is through educating clients about what this stuff is actually doing to them. And when it comes to trans fats, aspartame, and MSG, a recent study in Nutrition and Metabolism is perfect for just that.

If you get any kind of take out, eat any kind of processed food, or even if you’re just watching your calories, these additives might be more common in your diet then you think. Let’s talk about what this stuff is first to take some of the mysticism out of things.

1. MSG

MSG, or monosodium glutamate, tells you what it is right in the name. It’s the sodium salt form of glutamic acid. You probably know glutamic acid better by its amide form: glutamine. MSG is a chemical that is added to food to enhance flavor. When people say “enhance flavor,” think about the effect that regular table salt has on food.

2. Aspartame

Aspartame is a sweetener, but unlike regular old sugar, it doesn’t have the calories. It’s actually sweeter per gram than sugar as well. You’ll find this in many low- or no-calorie drinks and protein shakes.

3. Trans Fats

Trans fats are perhaps the most mysterious of the three. Many people know they’re bad, but don’t actually know what they are. Trans fats are a class of processed lipids (lipids include fats, oils and phospholipids). To make trans fats the oils are stabilized artificially. You may have heard the term “hydrogenated oil” instead. What these are is right in the name: they chemically bond hydrogen to the oil. A lipid that is fully hydrogenated is called “saturated,” in case you ever wondered where that term came from. The lipid is chemically saturated with hydrogen, which extends its life span. Food manufacturers add trans fats to foods to make them last longer.

In this study, researchers fed mice one of four diets: trans fat, trans fat with MSG, trans fat with aspartame, or all of the above. Then they looked at a variety of health factors. Since every group ate the trans fat, the researchers concluded trans fat negatively affected a variety of health factors. While the aspartame group had some bad and some good results, it was the MSG group that took a hard hit to their health.

One of the most interesting results was that when all the additives were consumed together, aspartame seemed to amplify the negative effects of the MSG. With increased triglycerides, leptin, fat deposits on the organs, fat in the blood, blood sugar, cholesterol, and liver damage, the results were shocking.

While most of us have heard these additives are bad, many may sneak them into their diets anyway. With the results of this study, these food additives might have just gotten a lot harder to swallow.


1. Kate S Collison, et. al., “Prediabetic changes in gene expression induced by aspartame and Monosodium glutamate in Trans fat-fed C57Bl/6 J mice,” Nutrition & Metabolism 2013, 10:44.

Photo courtesy of Shutterstock.

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