Fun Fitness Friday #2 - Carbohydrates

Welcome back for week number two of Fitness Fun Fridays. I had really great responses to last weeks post, so I want to thank everyone for their enthusiasm and input. I'm very happy that you guys learned something, and that there is such clamor and desire for nutrition and workout advice. I'll definitely keep this going every Friday. We have quite a bit of ground to cover, so let's get rock like my man Elvis.

Today we're going to enter some heated territory... the land of Carbohydrates. That's right. Put on the flame suits :) Nah, its' not that bad. Depending on who you talk to, there are VERY different opinions on carbohydrates and if you should eat them. I think it's similar to Dr. Seuss' "The Butter Battle Book", where there's quite a bit of fighting for no reason. So, with that in mind... I'm going to give you facts about carbs, how they interact in the body, and a little bit of my personal opinion. I think it works best that way, because with this knowledge you can make an informed decision about your personal tastes and diet. Oh, and by diet I mean lifestyle.

I like to classify and group things, because it helps to organize. Carbohydrates are broken into groups... the most common being monosaccharides, disaccharides, and polysaccharides. Now, don't get worried about the "funny looking words", we're not going to learn Latin here. I hate Latin... especially Ricky Martin :) I use the "Green Eggs and Ham" approach when it comes to Latin words. Break it down and sound it out.

"Mono" means one. "Di" means two. Poly means "many". So basically we have one, two, or many saccharides, or sugars. That's not too bad, right? The reason this distinction is important for nutrition is because complex and simple carbohydrates react differently in the body. Let's take a look...

Monosaccharides include: Glucose, Fructose, and Galactose... these are sugars found in blood, in fruit, and in milk, respectively. They are very simple, and therefore easily absorbed. The role of carbohydrates, which are sugars... is energy. They are the primary fuel for the body, kind of like gasoline for your car. With these specific sugars, no digestion is needed. Why is that important? Well, because the blood stream takes them up immediately. They don't have to visit the stomach or intestine to be broken down and absorbed. Eat them, and BAM, you have some energy ready to go.

Disaccharides are a combo of two monosaccharides. Examples are sucrose (table sugar), Lactose (yup the intolerant milk one) and Maltose. These sugars require digestion, so they have to stop by the mouth, stomach or intestine. Digestion breaks up sucrose into fructose and glucose, so the body can use it for energy.

Polysaccharides are starches, either animal or plant, and include glycogen, amyleopectin, and cellulose. These carbohydrates are long and complex, and require extensive work by your body to break them down.

So what's the big picture? Who cares about all this stuff right? Snoozefest dude. Well, hold on, I'll get to it.

When you eat carbohydrates... the amount of sugar in your blood rises... and your blood just can't keep it that way for long. It's like a bunch of crazy kindergartners running around, coloring on the walls and eating paste. So Kindergarten Cop, my bud Arnold, comes in on and sends them to different bus stops. He sends the kids, to one of three places... in this order, their fates are...

1) To storage in the liver or muscle as glycogen
2) To use instantly as energy in the body via glycolysis (gly=glucose, lysis= to break)
3) Trigylceride synthesis - aka "make into triglycerides" aka "turn into fat"

Arnold, Kindergarten Cop, is Insulin, and his job is to regulate blood sugar by sending it to one of those three areas. Sugar is sent to those places based on the bodies' given need at that time. So, if liver glycogen is depleted, the carbs you just ate will go there first, and then to the other destinations. If number 1 is full, then the sugar is shuttled to number 2, and then number 3.

Our bodies have an outstanding ability to keep and store energy for future use, as either fat, or glycogen, which is fancy, complex, stored up glucose. In a 70 kg individual (~155 lbs), the liver holds about 75 grams worth of glycogen, and about another 250 grams in muscle. Muscle glycogen is only used during activity, exercise, and movement, while the liver glucose is used for "bodily processes" beyond your control, and to maintain plasma. Liver glycogen runs out in about 3 hours. Do you every feel hungry 3 hours since you last ate? That's partly the reason. Let's put this all together.

Let's say you eat a peanut butter and jelly sandwich... peanut butter jelly time!

The bread (let's go with white to make it easier) and jelly are mostly carbs, and get broken down in the body. Look at the label...the jelly is composed of table sugar and fruit, which is simply sucrose, and fructose. The sucrose, a disaccharide, gets broken down in the mouth and stomach into glucose and fructose. The bread is made of flour, some fat, sucrose, and whatever else is on the label. While white flour is technically a polysaccharides, and therefore complex... it is refined, and without fiber, so it is easily broken down into monosaccharides also. So what our sandwich turns into is...

Jelly = fructose and glucose, and Bread = glucose. The peanut butter... that's fat and another post :)

The new fructose and glucose enters your blood stream after you eat it, and signals insulin to be released. Arnold comes along and shuttles the kids along to where they are needed. If it's been awhile since you've eaten... it'll go to the liver, or maybe you'll use it for energy, or maybe you'll store it for later as fat. The whole key to this process, if you think about it, is controlling insulin, and controlling where the carbohydrates will be utilized within the body.

If you just worked out... stored glucose in the muscle, or glycogen, is depleted. Any carbs you eat will go there, and therefore, cannot not be used as fat. If you took a relaxing day off and laid out in the hammock with a sandwich, the carbs will act in the same manner, and make the associated bus stops, but will may have a different final destination. Muscle glycogen is most likely already full, so when your liver glycogen is full, there's a good chance they will converted into fat.

I know we covered quite a bit of information there. But that's basically how carbohydrates work. They get a bad reputation because they have the ability to make a person fat. They get converted to fat if they are not needed at the given time. If you read and understand the "3 bus stops" insulin makes, you can use carbs to your advantage without getting fat. For example...

1. If the liver only has a 3 hour supply of blood glucose ready... it's a good idea to replenish that with small amounts of carbs - especially with breakfast (its been like 8 hours since yesterday right?)
2. After a workout, your body needs carbs because glycogen is gone... it's the number 1 stop
3. Try to eat carbs at the time of day you are the most active, and less when you are less active, because if you do not burn them, they have to go to stop #3.

I hope this clears up some confusion about carbohydrates in general. If any of this material is above anyone's head, or is too confusing, let me know. I'll field any individual questions when they arise. Next week we'll tackle the glycemic index, more carb theory, and some more practical information you can use for your own personal diets and food choices. Any recommendations, just shoot an email.
Green eggs found here.
Kindergarten Cop here
PB & J found here