Nutrition

Fuel for Thought

Weekly Column By Barb Bryan, BSc(Pharmacy), BSc(Nutrition) APA PRESCRIBING RIGHTS

Macronutrients – Part 2 in a 6-part series. Carbohydrates continued…

Last week we defined what macronutrients are and zoned in on the first major one of the three – Carbohydrates.

Good carbs, bad carbs, simple carbs, complex carbs — No wonder we can be a little confused when it comes to Carbohydrates!

What’s more, not all carbs are created equally. This week we will cover the 3 kinds of ingestible carbohydrates: simple carbohydrates, complex carbohydrates, and fiber.

1. Simple Carbohydrates: Monosaccharides & Disaccharides 

These are the carbohydrates that have the worst health reputation.  However, the way any reputation develops depends on the actions of others. If we used simple carbs in the right situation, at the right time, and in the right amount their reputation would inspire all other food molecules. We need to stop and ask ourselves, is it simple carbs that have the bad reputation or is it us and the way we misuse them? (Food for thought ?)

Simple carbs are either one sugar molecule, called monosaccharides, which include glucose, fructose and galactose or two sugar molecules joined together to form disaccharides which include sucrose, lactose and maltose.

  1. Glucose – aka “dextrose” is the major form of carb/energy in our body. “Bonking” refers to how an athlete feels when their glucose is low.
  2. Fructose – aka “fruit sugar” is absorbed differently than glucose in a non-competitive way.  However, it has to be converted to glucose in the liver before it can be used as fuel thereby making it a slightly slower carb ~ 4%)
  3. Galactose – aka “milk sugar” is a component of lactose. It competes with glucose transporter in the gut and like fructose, it too has to be converted to glucose in the liver before it can be used as fuel. However, we don’t see this monosaccharide in many sport nutrition products since its burn rate is about 50% of that of glucose and fructose.
  4. Sucrose (disaccharide) is a glucose + fructose molecule bonded together. Most gels and race fuels are a disaccharide. There are reasons we use disaccharides over monosaccharides for race fuel and we will talk about that next week. This simple carb just requires a bit more digestion in the mouth and small intestine to be converted to an immediate energy. But, the science shows us that the body uses 2 monosaccharides together better than one alone for fuel.

All of these kinds of carbohydrates can be found in refined sugars including the white sugar you see in a sugar packet, pancake syrup, and coca cola. If you have a hard candy, you’re eating simple carbs and if you eat organic honey you are also ingesting simple carbs. Simple sugars can be found in both non-nutritious and nutritious foods such as fruit and milk. It’s healthier to get your simple sugars from foods like these because extra sugar isn’t added. The sugar in these more nutritious foods is naturally occurring along with vitamins, fiber, antioxidants, phytochemicals and important minerals like calcium, magnesium, and potassium. In contrast, a hard candy has lots of sugar and doesn’t contain important nutrients.

In an athlete’s world simple carbs are key for performance and recovery and are found in most sport nutrition products. Simple carbs are the carbs to eat before, during, and immediately after exercise because they quickly give and replenish your body’s ready-to-use energy supply.

2. Complex carbohydrates: Starch (Polysaccharides)

These are different from simple carbs in that they’re made up of 3 or more monosaccharides bonded together like pearls in a long necklace. They are also known as polysaccharides. Their size allows for a slower, more gradual release of energy resulting in fewer insulin spikes and the feeling of fullness for a longer period of time. Obviously, this is not the carb we want to ingest right before a hard effort race when we will be in Zone 3-4 and maybe 5 since it would take too long to digest into glucose. Additionally, these larger carbs can create some GI distress along the way. However, it is VERY important to fill up on complex, nutrient-dense carbohydrates throughout the day, and utilize simple carbs for just before, during, and immediately after exercise.

Whole grains, beans, legumes, and starchy vegetables are all examples of complex carbohydrates. Complex carbs can have fiber and vitamins, minerals, and phytonutrients in addition to providing energy in the form of calories. However, as with simple sugars, some complex carbohydrate foods are better choices than others. Refined grains, such as white flour and white rice, have been processed, which removes nutrients and fiber. But unrefined grains still contain these vitamins and minerals.

In a well-balanced macronutrient diet for overall health, carbohydrates should make up 45-65 percent of your daily calories. For example, if you eat 2,000 calories a day, about 900-1,300 calories should come from eating carbohydrates. Divide that by 4 for the number of calories per gram of carb and this translates to about 225-325 grams of carbohydrates per day for a healthy adult. And,  most of those carbs should come from healthy complex carbohydrate sources.

3. Fiber

Fiber can be considered the forgotten polysaccharide carb! Although it’s not an energy source, it absolutely has health benefits. Fiber is a carbohydrate found only in plant foods naturally. Because our body lacks the enzymes to break it down, it mostly passes right through our system without being digested or absorbed. Most people know it keeps our digestive system running smoothly, but there are many other health perks to this indigestible carbohydrate.

There are two different types of fiber; soluble and insoluble and each have unique health benefits. For instance, the soluble fiber inulin acts as a probiotic for gut health. Also, the beta-glucan fiber in oats and barley helps reduce cholesterol, while the soluble fibers in legumes and lentils may better help control blood sugar levels. Fiber, also called roughage, can help you feel fuller, faster. The recommended daily serving of fiber is 25-35 grams.

To summarize, all three types of carbs are essential for overall health and sports performance. Understanding how quickly each is digested & absorbed and knowing the ideal timing of their ingestion is essential. From this knowledge, we can determine which type of carbohydrate we should be eating and when depending on our individual nutrition needs. I hope I’ve shown that all three can be part of a healthy diet depending on activity level and certain medical conditions.

Next week, in Part 3 of this series, we will touch on carbohydrates one more time and cover how they are uniquely involved in pre-workout, race, and recovery nutrition.