Introduction
In the last few decades, carbohydrates have played the hero and the villain, alternating back and forth so quickly you’re likely to get whiplash trying to follow the conventional wisdom of the day. More currently, some diets recommend a total rejection of carbs, portraying them as “bad” and the single largest reason why society has an obesity problem. But nothing is all bad. You’ve heard the saying, “don’t tar everything with the same brush”? Well, nothing could be more accurate when referring to carbohydrates.
In order to separate the wheat from the chaff, we have to look at the evolution of carbohydrate intake and where we are now. Today’s refined carbs may be fluffier, lighter tasting, easier to digest, and store longer on the shelf but are lacking in B vitamins, are devoid of almost all the grain’s original vitamin E content, contain none of the healthy oils from the germ, and even less of the original fiber. When we look at plant-based carbohydrates, we’ve shunned certain carbs because of the way they can affect our figure, forgetting about the beneficial fiber they contribute to our diet. And in addition, we are far less active than our ancestors so our bodies simply store the digested carbs for a later use. If the time to use the stored sugars never comes, excess weight certainly will.
The ultimate plan of attack is to consider carbohydrates the way our ancestors used to. When they ate carbohydrates, they got the full package, the whole grain; fiber, fats, vitamins, minerals, enzymes, and phytochemicals. The more active they were, the more carbohydrates they could consume because their bodies were actively breaking down and putting almost all of these sugars-from-carbs to good use.
The point we need to take away from all of this is we need to take in a balanced combination of carbohydrates each day, and monitor our activity levels, so that we can enjoy all the benefits of carbohydrates with less of the health issues that go hand-in-hand with over-consumption of too many of certain classes of carbohydrates. Moving through this chapter, we’ll take a look at exactly what carbohydrates are, how each type of carbohydrate affects our body, and how to create an effective balance.
What Are Carbohydrates?
Types of Carbohydrates
Carbohydrates are organic compounds linked together by building blocks, made up of carbon, hydrogen, and oxygen, called monosaccharides. The word “monosaccharide” means one (mono) sugar (saccharide). Monosaccharides are also referred to as “simple sugars”. The most recognizable monosaccharide is glucose, or blood sugar.
The marriage of two monosaccharides creates a disaccharide (double sugars), the most common of which is sucrose (the amalgamation of glucose and fructose).
Long, branching chains of linked simple sugars are called polysaccharides, the two most important to the body being starch and glycogen. In cells, carbohydrates are used as energy sources and structural components.
Simple carbohydrates have either one or two linked sugars, break down quickly where necessary, and occur either naturally in foods such as fruits, vegetables, milk and milk products or are added during food processing and refining. Refined, processed foods with added sugars have fewer nutrients than foods with naturally-occurring sugars.
Complex carbohydrates have three or more linked sugars and include starch and dietary fiber. Complex carbs take longer to break down into glucose and require more caloric energy than simple carbs to break them down. For example, it takes more calories to break down an apple than the apple actually contains. Complex carbs also enter the bloodstream more gradually than simple carbs, which helps keep blood sugars levels stable. Starch is broken down during digestion into glucose and used for fuel. Fiber’s composition is such that it can’t be broken down. Its benefits come into play when either soluble fiber binds to fatty substances in the intestines and carries them out as waste, thus lowering “bad” cholesterol levels, or when insoluble fiber helps push food through the intestinal tract, promoting regularity and helping prevent constipation.
As a side note, refined, or processed, carbohydrates are produced when whole plants which are high in carbohydrates are processed in such a way as to strip out everything but the highly digestible starch or sugar. This has the effect of concentrating the carbohydrate and/or breaking it down so that the body processes it very quickly, generally causing a high rise in blood sugar (glycemic response). It also removes the fiber and most of the nutrients in the food. Examples include white flour, white rice, white pasta, corn starch.
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| White flours White rice White Potatoes Syrup Honey Dairy Jams, jellies, marmalade Brown sugar Molasses Sucrose Fructose Maltose Corn syrup Soda | Spinach Turnip greens Lettuce Squash Artichokes Carrots Cucumbers Brussels sprouts Cauliflower Bok Choy Sweet potato, yams Broccoli Tomatoes Celery | Barley Buckwheat Oat bran Oatmeal Museli Wild rice Brown rice Whole grain products Beans, soybeans Lentils Peas Bulgar Quinoa Millet |
| FRUITS – Ask three people and you’ll get three different answers. Depending on how you look at it, fruits are either a simple carb or a complex carb. Fruits containing fiber and a lower glycemic index score, such as apples and oranges, are sometimes considered complex carbs. Fruits with less fiber and a high glycemic index score, such as watermelon, belong in the category of simple carbs. Fruit juices are nearly always simple carbs because they have no fiber and more added sugar. | ||
How Your Body Uses Carbohydrates
Our distant ancestors survived by hunting and foraging and their bodies, much the same as ours are today, had to do the best they could with what foods were available each day. There were no freezers to store last week’s catch of woolly mammoth in; it was either feast or famine.
Carbohydrates are a food source that supplies energy and the body likes to use this source right away. Once digested, carbs circulate in the blood stream as glucose. Aided by insulin secreted by the pancreas, the cells in the body gobble up the glucose as an immediate source of energy. Anything left in the blood stream gets stored back in the liver as glycogen for the next time there’s a famine. When the storehouses in the liver and muscles (and to a smaller extent in other organs and tissues in the body) are full, glucose is turned into fat for long-term storage so that none is wasted. When carbs in the diet are scarce, the body runs mainly on stored fats. If energy requirements exceed the amount of fat in the diet, the body taps into fat tissue for energy. Sounds ideal, right?
The problem begins when certain cells in the body which can’t run on fat, such as brain and nerve cells, start to make demands over and above what is being provided in the diet. Under low-carb conditions, the body begins to manufacture molecules called ketones. Ketones are related to a dangerous diabetic complication called ketoacidosis (high levels of poisonous ketones) which can sometimes occur if insulin levels are too low. To read more about ketoacidosis, CLICK HERE.
From Glucose to Energy
Inside your cells, the complex process of cellular respiration takes place. Cellular respiration is a process whereby the chemical bonds of glucose molecules are broken down and built back up again by enzymes into new molecules which then go on to become involved in further energy-making processes in the body such as the Krebs Cycle and the Electron Transport System. Cellular respiration is the process that all living organisms use to unlock the energy that is stored in their food as chemical energy.
There are two kinds of cellular respiration; aerobic and anaerobic and which one occurs depends on how much oxygen is present. Aerobic respiration (when sufficient oxygen is present) takes place in three stages; Stage 1 – Glycolysis (the breakdown of glucose), Stage 2 – the Krebs Cycle, and Stage 3 – the Electron Transport System. Because each of these three processes are very biochemically involved, we’ll simply give you a taste of how the first stage, or glycolysis, comes about. You’ll be glad we didn’t go on to explain the other two!
Stage 1 – Glycolysis
Glycolysis begins when two molecules of adenosine triphosphate (ATP), or to use the colloquial term “cellular energy”, are broken down by enzymes and donate 1 phosphate group each to a molecule of glucose. This new molecule then breaks down into two 3-carbon molecules. Enter more enzymes which oxidize these two new 3-carbon molecules, resulting in the formation of two new molecules of ATP, two new molecules of pyruvate (which go on to the Krebs Cycle) and two new molecules of NADH (which go on to the Electron Transport System). You can see that this cycle begins and ends with two molecules of ATP but all three stages of cellular respiration are designed to extract energy from glucose that your body can use to function.
As already stated, aerobic respiration requires oxygen. It is a slower process than anaerobic respiration. However it produces far more ATP and can go on indefinitely. Anaerobic respiration doesn’t require oxygen, happens far more quickly than aerobic, but produces far less ATP, a by-product called lactic acid, and can’t go on for long. Lactic acid build-up in muscles leads to cramps and burning. Anaerobic respiration also produces an “oxygen debt” in your body. This is why, even after you complete a strenuous exercise routine, your breathing is laboured and your heart rate remains elevated. Your body is trying to recoup and pay off the oxygen debt it acquired while you were exercising and probably not breathing as deeply as you could had you not been exercising.
Since every organ and tissue in your body is made up of cells, and a cell’s primary source of energy is glucose, every cell in your body needs this type of fuel to survive. Brain cells, in particular, depend on glucose for fuel, as do nerve cells (neurons). And the logical progression is this; if you want your muscles to move, your brain must first register the thought and then your neurons must signal the muscle to move. Neurons do not store glucose and depend on the blood stream to deliver a constant supply.
Low Carb, High Carb
What happens when you eat too few?
Contrary to what a lot of information out there will tell you, there are consequences to eating too few carbohydrates. As we’ve just learned, without the presence of carbs, fat is broken down into ketones. When ketones build up to excess proportions, your kidneys start to work harder trying to flush the overload out of your system. The consequences include dehydration, constipation, headaches, dizziness, brain fog, decreased energy and fatigue. Cutting out carbs also means that some vegetables, including the ones with increased fiber content, will be on your hit list, limiting your sources of vitamins, minerals and fiber. If an entire food group is eliminated from your diet, you could end up filling the vacuum with too much saturated fat and cholesterol, leaving you with an unbalanced intake of important nutrients. Some low-carb eating plans give you the impression that you can just keep eating and eating once you’ve cut out the carbs, eventually leaving you with the opposite intended effect. The ultimate sabotage is “carb creep”; this happens when you’ve restricted carbs from your diet and begin to feel the need to sneak in just one or two. Soon, you’re right back where you started.
 PORTION SIZES and PORTION CONTROL |
| 1 serving of meat, 3 ounces = the size of a deck of cards. 1 serving of fish, 3 ounces = the size of a cheque book. 1 cup of pasta or rice = the size of a tennis ball. 1 serving of dried fruits = the size of a golf ball. 1 serving of cooked vegetables = the size of a baseball (not a softball).  1 portion of baked potato = the size of a computer mouse.1 serving of pancake = the size of a CD. 1 serving of cheese = six pieces the size of six dice. |
What happens when you eat too many?
You may have already answered this question, depending on how you’re eating right now. Over-indulging in carbohydrates without using them up leads to weight gain, plus. Your liver can store approximately sixty to ninety grams of carbs as glycogen whereas your muscles store approximately four hundred grams. Once your liver, muscles and other tissues have stored all they can, the balance of glucose is stored as fat. If you store too much fat, you gain weight. Obesity is one of the risk factors included in metabolic syndrome. Along with obesity, insulin resistance is also included in these risk factors.
Insulin Resistance (IR) – Insulin is a hormone that is produced by beta cells which are scattered throughout the pancreas. Insulin is an important hormone that has a direct effect on the metabolism of carbohydrates, fats, and proteins and the desire of cells to remove glucose from the blood. It also regulates cell growth in the body. IR is a condition in which the cells of the body become reduced or resistant to the effects of insulin resulting in higher levels of insulin needed in order for it to have its intended effect. IR generally precedes the development of type 2 diabetes.
Think of it this way; insulin “knocks” at a cell’s door, the cell hears the knock, opens up, and lets glucose in to be used by the cell. If IR occurs, communication breaks down. The cell ignores the knock, the pancreas thinks the insulin isn’t effective and creates even more, which makes the knocking even louder. As long as the pancreas is able to produce enough insulin (loud knocking) to overcome this resistance, blood glucose levels remain normal. When the pancreas can no longer produce enough insulin, blood glucose levels rise and never fall (no matter how loud the knock), and type 2 diabetes sets in.
Don’t Rule Them Out Altogether – The Balanced Plate
So, what’s your recommended daily intake (RDI) of carbs? That depends on your Basil Metabolic Rate (BMR) and your daily level of activity. Your BMR is the absolute minimum amount of calories your body needs to keep it going at a dead standstill, e.g., if you lay still all day and never moved. To see the formula for finding your BMR, CLICK HERE.
Carbohydrates and Exercise
For arguments sake, let’s say your daily BMR is 2200 calories. Current wisdom dictates that we should get 50% of our daily calories from carbohydrates. Fifty percent of 2200 is 1100 calories. If you want that figure in grams, 1 gram of carbohydrate contains roughly 4 calories; 1100 divided by 4 equals 275 grams per day.
How do you get the very best balance of carbohydrates? Well, to get the best benefit from carbs, split your carbs into four categories: 30% should be “excellent” carbs (cruciferous & leafy vegetables, legumes, oats), 30% should be “good” carbs (fruit, root vegetables), 30% should be “intermediate” carbs (whole grain bread, wild rice, brown rice, whole wheat pasta, potatoes), and 10% should be “cheater” carbs (sugary candy, honey, licorice). Each category of carbohydrates provides very specific nutrients. If you choose from all four, you’ll get the best, all-round, nutrient values from your carbohydrates.
Your plate should contain twice as many carbs as protein. This doesn’t mean that you should eat twice as many potatoes as steak. Don’t forget; the majority of carbs came from plants. Your plate should contain a hefty portion of vegetables, a traditional carb such as a whole wheat bun or baked yam and a fist-sized portion of lean protein. To round it out, have a large glass of water, include healthy fats such as avocado or olive oil in your salads and finish your meal with fruit. Complex carbs take longer to digest and leave you feeling fuller, longer. But this also means that you’re likely to get sluggish and sleepy. Save your “large carb” meals for supper time and eat more fish, chicken, and salads for lunch, with only a small amount of carbs to get you through the afternoon.
There is no doubt that carbs are one of the best sources of energy for athletes. If you want to give your body every advantage when you exercise, you need to know when to consume carbohydrates, why and which ones are best.
Once carbs are consumed and digested, they move through the blood stream as glucose. Any glucose not immediately used by the body is stored in the liver and muscles as glycogen. Glycogen is the go-to source during the first few minutes of any exercise and is also used for any short, intense periods of exertion such as weight lifting or sprinting. In the long run, fat helps fuel our exercise with the aid of glycogen which breaks down the fat into a useable substance for our muscles. If the body is short on carbs, it will turn to protein as an energy source but this is counterintuitive as protein is a building block of muscle, not something we want to extract from muscle, break down, and use as an energy source.
The body usually stores enough glycogen to fuel a 30 to 90-minute bout of exercise. The larger your muscle mass, the more glycogen you store, but also the larger need to fuel the muscles. For a top notch workout, you should not only start with a full supply of glycogen but also replenish your stores during and after the workout.
Simple carbs from sources such as fruits, honey, potatoes, and white bread convert quickly and provide an almost immediate source of energy whereas complex carbs such as whole grains, beans, lentils, and oats which don’t digest and absorb as quickly provide a longer-term energy source. You should consume approximately 50 grams (200 calories) of these carb sources 90 minutes to two hours before you exercise if you plan on doing a moderate amount of exercise. If your routine is strenuous, you can consume more. If you are trying to lose weight, you may want to minimize your carb intake before your workout to approximately 25 grams (100 calories) since you’ll want your body to turn to burning fat as an energy source more quickly. Stay well hydrated before your exercise routine as well.
During training, alternate between sipping on a carb drink and water as there is the danger of consuming too many calories and negating all your hard work.
Within 15-30 minutes after your workout you should try to consume more simple carbs such as fruit or fruit juice. Research has shown that eating 0.3-0.6 grams of carbohydrate for each pound of body weight within two hours of endurance exercise is essential to building adequate glycogen stores for continued training. Waiting longer than two hours to eat results in 50 percent less glycogen stored in the muscle. The reason for this is that carbohydrate consumption stimulates insulin production, which aids the production of muscle glycogen.
If you are looking for the best way to refuel your body after long, strenuous endurance exercise, a 4:1 combo of carbohydrate and protein seems to be your best choice. While solid foods can work just as well as a sports drink, a drink may be easier to digest, make it easier to get the right ratio, and meet the 30 minute window. 1 If you prefer solid foods, try a peanut butter sandwich on whole wheat bread. Just make sure the bread is whole grain and the peanut butter is either low-fat or without additives. Or you can scramble an egg for protein and a piece of whole grain toast, or if you don’t eat eggs, try a piece of cheese or two slices of lean meat such as turkey.
A further consideration is cross-training and carbohydrates. Research has shown that glycogen depletion is localized to the muscles you work. Let’s say you train your legs today. During your workout, glycogen depletion occurs mostly in your leg muscles, but not much in your arms, chest, or elsewhere in your body. Hard training depletes glycogen from the individual muscles worked. 2. Use your glycogen stores evenly; alternate muscle groups worked each day.
Glycolysis, The Krebs Cycle, and The Electron Transport System, Glucose & Exercise
What to Eat Before, During and After Exercise, An Interview Christine Rosenbloom, PhD, RD, CSSD
Health Canada’s Age-Appropriate Food Guide and Serving Recommendations
What Does A Serving Look Like?
Carbohydrate Chemistry – Types of Carbohydrates, Explained
Complex Carbs vs. Simple Carbs – HealthiNation