Macronutrient Breakdown: Carbohydrates

Joe String

J Fitness

Performing cardio, lifting heavy, hell, getting to the gym and warming your body up—they all require energy. Your muscles are much more than physical attributes giving you confidence and your desired appearance; they are your motor. Knowing that, think about this for a second. You’re going on a long trip and only have a half of a tank of gas in your car. Prior to getting on your way, you would fill up, right? With a half of a tank, the car could only go so far, and unless you keep a reserve tank of gasoline on you, there is nothing else that can be put into the fuel tank that will allow the car to run optimally.

The exact same process should take place prior to a workout. Carbohydrates are the preferred fuel for your muscles! To give you a better perception of how and why, today we will take a look at carbohydrates on three different levels, give examples of low/moderate and high-carb sources, uncover why they are the optimal choice of fuel for the body and finish by exposing the myths of good and bad sources, and how they obtained these labels. Although this is the one non-essential macronutrient, it will become clear that their inclusion in your diet will lead to fantastic results and lifelong satisfaction.

Carbohydrates on a Molecular Level

In order to explain how carbohydrates work once consumed; I will go into their chemical structure. Much like the name states, carbohydrates are made up of carbon, oxygen and hydrogen. They are organic molecules and come in different types.

Within the category of carbohydrates there are monosaccharides, disaccharides and polysaccharides. The most basic forms are monosaccharides, otherwise known as simple sugars. Do not be alarmed; the name is given based on the fact that they contain only one sugar subunit, hence the prefix “mono.” Types of monosaccharides include glucose, fructose and galactose.

Knowing that a monosaccharide is a sugar containing only one unit, I’m sure you can assume that a disaccharide is a sugar containing two subunits (or two monosaccharides.) The two sugar molecules that make up the disaccharide will ultimately determine what exact disaccharide we’re dealing with. For instance, the combination of fructose and glucose will make the disaccharide sucrose (table sugar), and the combination of glucose and galactose will make lactose (milk sugar). Both of these disaccharides also fall under the category of polysaccharides.

Polysaccharides are what we like to call complex carbohydrates. The name comes from their formation from multiple units, creating a more complex molecule and thus, being more difficult to break down. Common polysaccharides are starch and cellulose. Both of these molecules contain the same subunits but the nature of which they are bonded brings about their unique structure.

Carbohydrates on the Food Level

Now I want to take the time to explain where carbohydrates can be found in foods and what other macronutrients these foods contain. Furthermore, I will include foods rich in micronutrients to help satisfy your overall daily nutritional goals. This will give you an idea of what types of foods contain high, moderate and low amounts of carbohydrates and assist you in deciding on what kinds of foods you want to try and fit into your day.

Starting with foods low/moderate in carbohydrates are obviously going to be, well, high protein sources (for the most part.) You’re not going to find high amounts of carbs in meat, eggs, fish or whey powder. I would hope that you do not plan on using these foods as carb sources anyway. Also low in carbohydrates are most fat rich foods such as nuts, cheese/dairy products and of course, oils. Now, foods that are low in carbohydrates that are used during a lower-carb diet would be your fibrous vegetables—broccoli, spinach, cauliflower, green beans, carrots, etc. These are all polysaccharides and contain high amounts of micronutrients and fiber as well as low amounts of fat, protein and therefore, overall calories. Also very low in carbohydrates are a few starchy vegetables such as pumpkin and squash along with some fruits, like berries and watermelon.

Finishing up the foods portion, I want to cover foods that have a high carbohydrate count. These are the foods that, especially when in a caloric surplus, can be consumed in vast amounts without worrying about going too far. With that said, there is no reason these foods can’t be consumed in a caloric deficit, just be aware of your portion size.

First on the list we have all grain-based foods—rice, quinoa, pasta, oats, breads and cereals. Aside from rice and cereals, these foods contain somewhat notable amounts of fat and/or protein, but are still over 80% carbohydrate. Next, we have the starchy vegetables and beans; these are all sorts of potatoes, corn/peas and beans/legumes. The grains and starch groups both contain large amounts of micronutrients, fiber, and some contain low/moderate amounts of protein. Finally, closing out the high carbohydrate food group we have foods containing sugar. Within this group, I consider two subgroups—nutritious/wholesome, and then processed. The nutritious and wholesome group contains the higher-in-carb fruits like bananas, apples, oranges, pineapple, etc. These foods contain pure carbohydrates. The processed group contains anything with added sugar—pre-packaged pastries, sweet snacks, bagged snack foods and frozen desserts. A majority of these foods contain large amounts of fat and calories, but there is no reason to not consume them if they fit into your macros.

Carbohydrates as an Energy Source

When carbohydrates enter your mouth, they begin to be digested instantly. No matter the carbohydrate source (with the exception of fructose [see The Fructose Debate], it is converted to glucose throughout the digestion process. Once completely digested and into the blood stream, the pancreas is signaled to secrete insulin. Insulin is the hormone responsible for driving this glucose into the muscles for energy as needed.

The reason that carbohydrates are the optimal source of energy by the body is because they are readily converted into glucose, which is then converted to muscle glycogen. Other sources of calories (protein and fat) are not as efficient as a source of energy because they go through a different process during digestion and are not as-readily converted to glucose as carbohydrate. Plus, since glucose is a carbohydrate itself (and a simple one, at that) it is a very quick process for the body to convert any other carbohydrate into it.

Carbohydrate Myths

The amount of myths that surround the consumption of carbohydrates cannot be counted on both hands and both feet—there are just way too many. However, that never-ending list can be summed by two topics that I believe need special attention and disproving. This list consists of carbohydrate timing and of course, the glycemic index.

The myth behind timing carbohydrates got its beginning from the fact that any glycogen not used by the muscles is stored as fat. Although this is a fact, allow me to explain why consuming carbohydrates at one time will result in no better or worse outcome than any other time. Your body will use its required amount of energy throughout the course of a day regardless of the time it is consumed. If you remain within caloric range consuming your biggest meal directly before bedtime, the depleted levels of glycogen from the day’s activities will be restored and your body will utilize it while you sleep into the next morning. It’s a never-ending cycle that elicits the same results regardless of the timing of your carbohydrates.

I wanted to save the glycemic index for last because there are so many components to the argument and countless myths surrounding it. The glycemic index (GI) is a value given to a source of food that tells you the effect it will have on the body’s insulin response. Foods with a higher GI value cause more insulin to be released while lower values require less. The idea is that when more insulin is present, glucose moves more rapidly through the blood and into storage, which will result in increased body fat. The idea makes sense, but stemming back to the faulty argument of carbohydrate timing, “If one remains within caloric range, this stored energy will be released and burned.” That means, regardless of the body’s insulin response after consuming a form of carbohydrate, remaining within your daily energy requirement will keep your body the same. The only thing to take into account in regards to the glycemic index is satiety. When on a diet and looking to keep calories low, staying full is extremely important. Thus, choosing foods that elicit a rather weak insulin response will take longer to digest and therefore, will leave you feeling fuller, longer. However, consuming a food with a greater response of insulin and being able to use will power to remain within daily energy requirements will result in the same outcome (just be prepared to fight hunger!)

Another reason that the GI is a poor indicator of carbohydrate quality is that any other food consumed with that carb containing fat, fiber or protein will delay digestion. This blunts the body’s release of insulin and completely disregards the food’s glycemic load. Other arguments that came from the glycemic index were post-workout insulin spiking, structuring your eating pattern so that carbohydrates were never consumed alone and the need to only eat high fiber forms of carbohydrates; all of which have been proven false.

Wrap Up

So now we can all see how carbohydrates are structured, broken down, where they are found, how they work and their myths. Clearly, carbohydrate dense foods provide us with great energy, caloric value, micronutrients and great taste/variety. It is rather bizarre to think that many people used to believe in some of the claims made in the fitness industry about our primary source of fuel; I hope any questions or concerns you have about carbohydrate consumption have been made clear today!