Cyclists, does this sound familiar?
You’re 50 km away from the end of your ride and you start to get that feeling – stomach churning, heavy legs – you’re bonking and you need something now. So you pull up to a convenience store and walk the aisles wondering what to eat to save your ride.
Ironically, what causes the bonk in cycling and what will save you is the same thing – carbohydrates. But have you considered that all carbs are not equal?
Carbohydrates are one of the main macronutrients that the body uses for energy (the other two are fat and protein). They’re the body’s main source of energy.
There are three main forms of carbohydrates: sugars, fibers and starches. You might have heard the term “simple” carbohydrates. This refers to sugars because they’re smaller molecules that break down quickly in the body. Fibre and starches are considered “complex” carbohydrates because they have a larger molecular structure and are more challenging for the body to break down.
The body burns carbohydrates for fuel, but if they’re not needed right away, they can be stored in the liver and muscles in the form of glycogen. This is known as “carb loading.”
Role of Carbohydrates in the Body
Simply put, carbohydrates supply your central nervous system (your brain and spinal cord), and muscles with the energy they need to function.
During endurance sports, like cycling, carbohydrates provide about half of your body’s total energy needs. This allows the body to perform well and prolong hitting “the wall” (or bonking).
Simple Carbohydrates are small molecules that the body breaks down and absorbs easily. They’re the quickest form of energy for the body. Eating fast carbs will raise your blood sugar quickly and give your body fast fuel that it can use up right away.
Foods that contain fast carbs are: fruit, dairy products, honey, and maple syrup.
Complex carbs, on the other hand, are more slow burning because they’re composed of longer strings of simple sugar molecules. They take longer to break down and be released as glucose in your bloodstream. Thus, complex carbohydrates supply the body with energy more slowly than their simple counterparts.
Complex carbohydrates include starch and fibre found in whole grains and grain products like bread and pasta, beans and root vegetables (potatoes and sweet potatoes).
Which Carbohydrates to Choose
The Glycemic Index (GI) is a common measurement for the rate at which a food will increase blood sugar levels once consumed. It helps us understand how fast or slow a food really is, when it comes to delivering fuel to your body.
For reference, a value of 1 is considered the slowest and a value of 100 being the quickest (pure glucose is used as the reference).
For example, a food with a GI of 36 will spike your blood glucose by 36% of what pure glucose would.
So what’s considered high on the Glycemic Index? Foods with a GI of 70+ are considered high glycemic food.
You might be wondering whether to choose low or high GI foods. It turns out, both have their benefits:
- Slow carb (low GI) foods will keep you feeling full longer because they energy slowly. These are great for weight loss, or everyday fuelling.
- Fast carbs (higher on the GI scale) are helpful for energy replenishment during exercise, especially during endurance activities like running or cycling.
When you’re fuelling for a ride that will take a few hours, try taking in low GI items early on. These are things higher in fibre like a dense granola bar. Then, switch to higher GI foods as the fatigue sets in on your ride.
The glycemic index is a helpful tool for fueling your rides and making healthy lifestyle choices, but it shouldn’t be the only thing considered.
The nutrient quality of the foods you choose on a regular basis should also be factored in. It’s a good idea to also consider the quantity and time since your last meal.
There’s no one way to fuel properly for everyone. Knowing your body and paying attention to how you feel when you exercise and eat certain foods will help you make the best decision possible for you.
So next time you find yourself at a convenience store mid-ride, you’ll know which choices will give your muscles a quick boost of fuel, and which will be slower burning and longer lasting. Mix up your carb choices to find what works best for your body.