In this lecture we're going to look at the first of three macro-nutrients, the carbohydrates. Macro-nutrients are those which provide us with energy and when you study nutrition energy essentially means calories. The macro-nutrients that gave us calories are carbohydrates. Fats and proteins. 1 gram of carb you can see here, has 4 calories per gram. A gram of fat has 9 calories and a gram of protein has 4 calories. Vitamins and minerals are our micro nutrients and they don't provide energy. So if your friend tells you he's taking a B complex vitamin for energy. It's quite obvious that your friend doesn't understand the concept of energy. There are no calories in vitamins or minerals. Alcohol is another component of some people's diet and it certainly does yield calories at 7 calories per gram. So an important concept check: 1 gram of carb. Gives us four calories, 1 gram of protein, gives us four calories. One gram of fat gives us nine calories, and a gram of alcohol gives you seven calories. Vitamins and minerals do not yield calories or energy. A little bit about carbohydrates as a whole. Carbohydrate should constitute the majority of calories in a well balanced diet. Some people are surprised to learn that. They've been on a low carb diet or they think carbs make them fat. But you'll see in a moment, that they really should be the majority of where your calories are coming from. Carbohydrates are group of compounds that are made up of one or more sugar molecules. And we sometimes abbreviate it CHO, so that's short for carbohydrate. Also referred to as carbs. Carbohydrates are made up of carbon, hydrogen and oxygen. In our food supply we get carbohydrates from foods like fruits, vegetables, milk and legumes. Legumes are things like dried peas and beans, or lentils. We have simple carbohydrates and complex

carbohydrates. Simple carbohydrates include Mono-saccarides. And disaccharides. Mono means 1, so that's a carbohydrate made up of a single sugar unit. There are 3 monosaccharides, glucose, galactose and fructose. Disaccharides are simple sugars made up of 2 sugar units, di meaning 2. And the 3 disaccharides you should know about are maltose, sucrose and lactose. So, jump back one to the manosaccharides looking a little bit more closely at glucose, galactose and fructose. The way you can remember glucose is that its the most abundent on the manosaccharides. It circulates regularly in your blood so when we study diabetes, we'll look at your blood sugar levels as well as your blood glucose levels. The lactose is a monosaccharide that doesn't occur freely in nature that often but it does make up 1/2 of the molecule called milk sugar. Lastly, we have fructose. Fructose is a monosaccharide, and we also refer to that as fruit sugar, so you can think F for fructose, F for fruit sugar. Fructose makes up half, is made up of half sugar, in honey and high-fructose corn syrup, and it's used to sweeten many beverages and foods. Your disaccharides again, are maltose, sucrose, and lactose and what's interesting about each of the disaccharides is that they all contain one molecule of glucose. Maltose is actually made up of 2 molecules of glucose. Sucrose is made up of glucose plus fructose. We also refer to sucrose as table sugar. So, when you hear sucrose and the word sugar, those are used interchangeably. Lactose is made up of one molecule of glucose, and one molecule of galactose. Lactose is also what we also refer to, as milk sugar. You'll notice, again, each of the three disaccharides have one thing in common, and that's one molecule of glucose. So, maltose in summary, that;s the disaccharide, made up of one molecule of glucose, and another molecule of glucose. It's formed when starch is digested. And it's broken down by salivary amylase. So if you take a cracker, and you put it

on your tongue, and you don't chew it. You sometimes, or you can't always, you should be, if you're making salivary amylase. You feel that cracker start to disintegrate, okay? And the maltose is the slightly sweet taste that you experience when you hold that cracker on your tongue. Sucrose, again, is table sugar. And in the United States, it's the only sweetener that can be called sugar on labels. So you'll learn that there's lots of other words that describe sweeteners, but if it says sugar on a food label, the manufacturer's referring to sucrose. Which is one molecule of glucose plus one molecule of fructose. And lastly we have lactose. That's a disaccharide that we call milk sugar. You see a picture of ice cream here. For people that have lactose intolerance, it means that they lack the enzyme required to break down the sugar lactose. Note that each of these sugars end in OSE. That's an indicator if you see OSE that we are dealing with the sugar.When you see a related word that ends in ASE that indicates that its an enzyme.So you require the enzyme lactase in order to break down the milk sugar lactose . Lactose. People that are lactose intolerant don't make enough or don't make any of the the enzyme lactate. They eat that sugar lactose, their body can't break it down. They get a whole host of of undesirable G.I. side effects. So our simple carbs are our monosaccharides and our disaccharides. [INAUDIBLE]. Our complex carbs, there's 3 of them. Glycogen, starch, and fiber. And together, we refer to the comp, complex carbohydrates as polysaccharides. Poly means many. Glycogen is the storage form of glucose in humans and animals. We are a human or a type of animal, perhaps. And we store glycogen in our liver. And in our muscles. So, if you weren't to eat for a very long period of time, your body would break down the glycogen in your liver and your

muscles, to some degree, to give you some glucose. Starch is a little bit different in the sense that, that's the storage form of glucose in plants. And then, fiber is the third type of complex carbohydrate. And that's the indigestible, non absorbable plant remnant. How many calories per gram does fiber give, well that's kind of a tricky question, because we actually don't digest,nor do we get any calories from fiber containing foods.So, these are complex carobs,or let me also refer to,as our polysaccharides. So again, we've got glycogen, this is the storage form of glucose, in humans and in animals. We've got starch, which is how plants store their glucose and then we have fiber. You might notice that the glycogen here, it's made up of highly branched chains of glucose. The branching allows for your body to quickly breakdown the glycogen. To give you glucose if you should need it for energy. Starches can have either straight, or branched, chains. Starchy foods include things like breads, legumes, and starchy vegetables. And then we have fiber. Fiber is made up of either straight, or branched, chains, of monosaccharides. Human enzymes can't break down, many of these sugar links. And cellulose is a type of fiber that we find in wheat bran and broccoli. That's the picture that you see here, and cellulose is a fiber made up of straight chains of glucose. So I mentioned briefly where we get carb in our diet, but this slide shows you in a little bit more detail. The carbohydrates from certain dairy foods, from milk and from yoghurt, but there is no carbohydrate in cheese, because the milk sugar, lactose, has been removed during processing. That is why some people with lactose intolerance can actually tolerate more readily than they can, let's say yoghurt or icecream. There's about 15 grams of carb, in a medium sized piece of fruit. And vegetables, while they have carbohydrates, have a little bit less. You see 5 grams of carb, in your typical

non-starchy vegetable. When we look at diabetes, we'll talk a little bit more about the difference between starchy and non-starchy vegetables. Breads, pastas, rices, tortillas, cereals these starchy bread foods give us, in about one ounce or one Slice of bread serving, 15 grams of carbohydrate. And generally, 15 grams of carbohydrate will come in a serving that gives you about 100 calories. Legumes, the dried peas and beans, they vary, but somewhere between 15 to 20 grams per 1/2 a cup. A serving of those. There's no carb in meat. There's no carb in oil and fats. But there's lots of carbohydrate in sugars and added sugars. And to put it roughly, a teaspoon of sugar. That's table sugar, sucrose, gives you 4 grams of carbohydrate. How do we know how much carbohydrate we need? Carbohydrates should, in a well balanced diet, accept in very rare medical conditions, constitute the majority of your calories. And it should be about 45 to 65% of the total calories that you eat in a day. Now, most people, I would assume taking this class, are somewhere in the 1 to 50 plus year-old category. Category. It's pretty much the majority of our population. In the United States, the Institute of Medicine tells us, that based on their science, they say all human beings need an absolute minimum of 130 grams of carbohydrate a day. I'll show you in a second that most of us need more than that, but at the bare minimum, you should never be following any sort of diet that takes you below 130 grams of carb. Now for those of you that have been on a low carb diet in the past, there is lots of fad diets and nutrition plans out there that are not based in scientific evidence that say, eat well under 130 grams of carb. We know if you eat less than 130 grams of carb a day, you're not going to be getting all the amounts of different important vitamins, minerals, et cetera that your body needs. Carbohydrate needs go up When you're pregnant and when you're lactating.

One thing that's interesting about carbohydrate needs is that a one year old needs, at a minimum, 130 grams of carb. A 65 year old needs, at a minimum, 130 grams of carb. Most of the differences in nutrition between one year olds and 65 year old would be based on their weight. But carbohydrates, it's a static number, 130 grams. That's why it's important for very little children to have frequent meals and snacks. They can't get all of that carbohydrate in 3 meals like you or I as an adult can. So, again the amount of carb for 1 year old is the same as it is for a 50 or 60 year old and those are minimum amounts. Let's do an application. We've got a 23 year old male. Perhaps he's a student in this class. He's an elite athlete and an endurance runner. Elite athletes and particularly endurance runners need more or a greater percentage of calories from carb than the average non-athletic person would. So he met with a dietician and the dietician estimated he needs about 3500 calories per day. In order to meet his needs while he's training. As he's getting closer to his competition date the dietician who specializes in sport nutrition says, listen you want to increase your carb to about 70% of your total calories. So I'd like you to take a moment to figure out, knowing a couple of pieces of information how many grams of carbohydrate per day this athlete needs. And one thing to keep in mind is that every gram of carbohydrate, you get 4 calories per gram. Okay? So take a moment again and figure out how many grams of carb per day should this athlete be eating in order to get 70% of the 3500 calories from carbohydrate? Here's the solution. Hopefully you got the answer which is 613 grams of carb. And if you didn't, or if you did, here's how you get there. The question is asking you how many grams of carb a day he needs. 70% of the calories should come from carb as he approaches his performance. 70% of 3500 is 2,450 calories from carb. Now that's a good piece of information but the question didn't ask how many

calories from carb. It asked how many grams of carb. In the information that we see on food labels it's listed in grams of carbohydrates. So if you got 2450 calories from carb and you know that every gram of carb has four calories you divide 2450 by four to come up with the answer that's roughly 613 grams of carb. Now you know at the bare minimum he needs 130 but as an elite athlete he's certainly up in the 600 range, needs alot more carbohydrate then you would for the bare minimum to sustain life. If you're interested in learning more about carbohydrates, I've got a couple of good links for you here. Medline Plus, which is a, from the United States, the National Library of Medicine, has a good jumping off page to learn about carbs. As does the Centers for Disease Control, and the Food and Agriculture Organization has some good information for you about the role that carbohydrates play in human nutrition. Lastly, you might want to check out the patient education piece on carbohydrates, from the University of California at San Fransisco.