 Hey everybody, Dr. O here. In this video we're going to introduce the carbohydrates and talk about the monosaccharides. So the word carbohydrate means hydrated carbon because they're made of carbon, hydrogen, and then oxygen. Carbohydrates are called saccharides, another word meaning sugar. So we're going to look at the five monosaccharides, really only three we care about, at least for this video. We have the hexoses, which are called that because they have six carbons in that ring, and those are going to be glucose, fructose, and galactose, come right back to them. And you do have the two pentoses because they have five carbons in this ring. This is going to be deoxyribose and ribose. Maybe you've heard of deoxyribonucleic acid, DNA, and ribonucleic acid, RNA. So we'll cover the pentoses separately because we're primarily looking at the dietary monosaccharides here. Let's take a look at the three, glucose, fructose, and galactose. So carbohydrates like this have four calories per gram. You'll see that fat has nine calories per gram because both carbs and fat have carbon, hydrogen, and oxygen, but fat has a lot less oxygen, so you can cram a lot more hydrocarbon onto a spoonful, I guess. So glucose is the only carbohydrate our body uses. Fructose and galactose are great, but they have to be converted to glucose by the liver before they can be used for fuel. That can be good or bad, depending on what you're looking at. So glucose is, like we talked about blood sugar, we're actually talking about your blood glucose levels. Glucose is the key fuel. Glucose is what your body loves to turn into ATP, especially when you're physically active. Carbohydrates are your primary fuel source during physical activity, but we'll talk later about how fat is your primary fuel source when you're resting. So fructose is what's known as fruit sugar. It is sweeter than glucose, so you probably, well, we can, oops, sorry. So fructose is fruit sugar, and as you'll see there, it's going to be part of sucrose or your table sugar, and then we'll talk about high fructose corn syrup and those kinds of things later. But it is sweeter than glucose, which is why humans love to eat it. And then galactose, you can see like the name implies, is going to be part of lactose or your milk sugar. So glucose, fructose, and galactose are your three key monosaccharides, and we eat all of them, but they need to be converted to glucose before they're used, which is why if you have a diet high in fructose, it doesn't actually raise your blood sugar, which is why you'll see like a lot of diabetic things or some things are touted as being good for your blood sugar control because they have a lot of fructose, but your body will turn into glucose. It's actually going to be taxing your liver, which is why I believe that too much fructose is really, really hard on the liver and potentially even hepatotoxic. So we'll cover all that in much more detail on nutrition. I'm just introducing the monosaccharides right here for now. Okay, so those are your monosaccharides. I hope this helps. Have a wonderful day. Be blessed.