August Post: Nutrition 101 – Carbohydrates
Continuing our macronutrient discussion From June, we will delve into Carbohydrates this month, affectionately referred to as Carbs. Much like protein, carbohydrates are composed of carbon, hydrogen, and oxygen atoms, however, they do not contain nitrogen atoms. Their primary role in humans is to serve as an energy source through the form of sugar.
Carbs can be classified into three groups according to the number of sugar units they contain, Monosaccharides (single sugar molecules), Disaccharides (two simple sugar units joined together), and Polysaccharides (complex carbohydrates which can contain up to thousands of sugar units). We will break these down further below.
Monosaccharides consist of glucose, fructose and galactose, with glucose being the most common. Glucose is a building block for many larger sugars, and is present circulating in the blood (as your blood sugar) and stored as glycogen in your muscles and liver to be used as energy. Fructose is similar to glucose, but has a different atom arrangement which makes it taste much sweeter than glucose. Fructose is naturally present in fruits and vegetables. Galactose is a milk sugar, and gets its name from the Greek galaktos (milk) and the generic chemical suffix for sugars -ose.
Disaccharides consist of sucrose (glucose + fructose), lactose (glucose + galactose), and maltose (glucose + glucose). Sucrose is the most common and is known as table sugar, and lactose is only found in mammalian milk. Maltose occurs primarily when polysaccharides are broken down during digestion, or during the fermentation process of alcohol and is the primary carbohydrate in beer.
Polysaccharides consist of starches, dietary fiber, and glycogen. Starch is the storage form of glucose in plants, and grains, nuts, legumes, and vegetables are all good sources of starch. Important to note, before starch can be used as a source of energy, it must first be broken down into its glucose components. Dietary fiber is a constituent of the plant cell wall, and includes cellulose, hemicellulose, beta-glucans, and pectins. Glycogen is found in small amounts in human and animal tissue as a temporary source of stored energy, although it is not present to any large extent in the foods we eat. Therefore, when glucose enters the muscles and liver, if it is not metabolized for energy it is synthesized to form glycogen through the process of glycogenesis.
All types of dietary carbohydrates, sugars as well as starches, are effective in supplying us with glucose and glycogen (energy). Consumption of a mix of sugars and starches is desirable though, as a varied source of carbohydrates will increase the amount of micronutrients (vitamins and minerals) available to us, and limit boredom with food selection – variety is the spice of life after all.
But carbs are the enemy, right? Well, not really. While the body does not technically need carbohydrates to survive, they do provide a great source of micronutrients and variety to our diet as mentioned above. They also provide quick energy for exercise and activity, which is something that most of us do every day! What should be the main focus is what type of carbohydrates and how much should be consumed.
Carbohydrates, while varied in nature, should consist of mostly whole foods and avoid processed foods. A good rule of thumb is to stick with vegetables, nuts and seeds, and fruit while avoiding pure or added sugar as much as possible. Reason being, vegetables and fruit contain significant amounts of water and fiber which help to make you feel full faster. I am sure I’m not the only one who can crush a bag of M&Ms in one day and still be hungry, so let’s do the math. One “share size” (lol, right?) package of M&Ms has roughly 46 grams by weight of candy, and 28 grams of carbohydrates, most of which is in added sugar. A half cup of chopped broccoli (roughly 44 grams by weight) has 3 grams of carbohydrates. That means that you would have to eat 4.5 cups of chopped broccoli to eat the equivalent number of carbohydrates! I don’t know about you, but that is a LOT of broccoli and would be very hard to accomplish and still want to eat more food. Now, don’t be the person that avoids the birthday cake, but try to limit your carb selections to the healthier alternatives.
As for quantity, at the bare minimum, about 50 to 100 grams of carbohydrate per day is needed to prevent ketosis. And yes, for most people ketosis is not a desired state, especially athletes. As a reference, a medium banana has roughly 27 grams of carbohydrates, so it does not take much to avoid ketosis. Beyond that need, carbohydrates provide fuel for energy, so consumption should match your activity level each day. The CrossFit recommendation does state: keep intake to levels that support exercise, but not body fat. If you feel your workouts have been lagging lately, you might consider bumping up your carbohydrate intake, especially a few hours before you go to the gym.
My personal recommendation, and something that I and many others have found success with, is to try E.C. Synkowski’s 800 Gram ChallengeⓇ. This “diet” makes things very simple: eat 800 grams of fruit and vegetables (by weight) each day, and if you are still hungry after that, eat whatever you want! By adding fruits and veggies and not restricting any food items, this way of eating encourages you to fill up on high quality, natural foods so that you are not hungry to eat the less ideal sugary items. Give her site a look over and I encourage you to try it out!
Photo compliments of ownyoureating.com