This is What Happens When You Eat Carbs and Fats Together

Oh yes. That tasty and creamy feeling of the pasta is unbelievable! All this cheese…so good!

You know that feeling. I know that feeling. It’s amazing.

But is it a good idea to eat a bunch of carbohydrates and fats in terms of calories and weight loss?

Oh, I know what your thinking. “It’s calories in vs calories out at the end of the day. It doesn’t matter if I eat a bunch of carbohydrates and fats at once or a bunch of anything else at once.”

“Calories in vs. calories out” or science. Which one are you going to believe?

I believe science and you should too.

When you consume carbohydrates, it gets broken down into glucose in the small intestine.

Afterward, the glucose gets sent out of the small intestine via blood vessels. Now lets briefly look at how fats enter the bloodstream.

After you consume fats, it makes its way down to the small intestine.

However, fats don’t leave the small intestine via blood vessels because the size of chylomicrons (lipoproteins that carry mostly triglycerides and cholesterol) are too big to fit in the blood vessels.

Because of this, the fats packaged in the chylomicrons enter lymphatic vessels called a lacteal. These lacteals mostly empty in the vein near the left and right thoracic duct. Afterward, the fats packaged in the chylomicrons get pumped out and into the bloodstream via the heart.

Alright sweet. Now we know the basic idea of how fat and glucose make their way into the bloodstream. So the question still remains: why shouldn’t you eat carbohydrates and fats in one meal?

Insulin!

Yeah. I know. I’m completely being serious right now. Insulin is the reason why you shouldn’t be combining a ton of fats and carbohydrates in one meal.

As I briefly explained above, when you consume carbohydrates, insulin gets released via the beta cells in your pancreas. The insulin then binds to your cells’ receptors which causes the cells to “open”. Why?

The cells need glucose for energy! The insulin binding process is how blood glucose decreases! However, keep in mind that all the creamy fats you ate in that pasta are also swimming in your bloodstream near the glucose! So what do you think will happen when the insulin binds to your cells? Obviously, the glucose and other nutrients will “enter” the cell, but what else will enter?

Fat!

Exactly!

For those of you who want to know more as to how the fat and sugar/carbohydrates enter your fat cells, below will be a little more science for you to read.

We must pick up from where I mentioned the chylomicrons in the blood stream. Remember, the chylomicrons were lipoproteins that were made up of protein/phospholipid covering and were responsible for carrying the cholesterol and fats/triglycerides throughout the bloodstream.

Another important factor to mention is that when the chylomicrons left the intestinal cells, there was a certain protein put on the chylomicrons. This protein was an apo-B48 protein. When the chylomicron gets into the blood stream, HDL (high density lipoprotein) donates two more important proteins which are an apo-c2 and an apo-E protein.

The apo-c2 protein is what binds to lipoprotein lipases throughout the blood vessels. Lipoprotein lipase enzymes help break down the triglycerides into glycerol and free fatty acids. These free fatty acids enter the fat cells/adipocytes and the glucose nearby in the blood stream also enters the fat cells due to the presence of insulin and GLUT-4 receptors.

The glucose that enters the adipocytes can enter glycolysis (which is the beginning stage of cellular respiration in which glucose gets broken down into two pyruvates) and get converted to dihydroxyacetone phosphate. The dihydroxyacetone phosphate can then get converted into glycerol. Glycerol can then get converted into glycerol-3-phosphate.

So now you have fatty acids from the fat you consumed and the glycerol-3-phosphate because of the carbohydrates you consumed. The glycerol-3-phosphate and the fatty acids in the adipocytes can now combine and form triglycerides or fat (with the help of acyl-transferase enzymes)!

There is so much more science into this, but it is still fascinating to me that all of this science is occurring inside us!

This is why I believe that it does matter what you eat! I mean doesn’t it make sense? At the end of the day, for example, I would gain more fat inside my cells if I ate 1000 calories worth of mostly carbohydrates and fats compared to 1000 calories worth of mostly proteins and fats.

See?

Even though you ate the same amount of calories, it still mattered what you ate.

As you can see, it’s not always about “calories in vs. calories out.”

You could eat the same amount of calories in two different meals, but one meal can cause your cells to gain more fat (carbohydrates and fats) and the other meal won’t make your cells gain nearly as much fat (proteins and fats or another combination that doesn’t involve carbohydrates and fats together).

Disclaimer: The original version of this article can be found here: https://medium.com/p/a75d80c398f6