Carbohydrates have gotten a bad rap over the years, but they’re one of the body’s most important fuel sources. Whether you’re walking the dog, crushing a workout, or just trying to make it through your workday without snapping, carbs help you do it.
What Are Carbohydrates and What Do They Do?
Carbohydrates are one of the three main macronutrients, alongside protein and fat. Most come from plant-based foods and exist as sugars or starches. They’re your body’s go-to source of quick energy and are especially important during physical activity.
Carbs also play a critical role in brain function. Fun Fact: your brain actually runs primarily on glucose (a simple form of carbohydrate).
Simple vs. Complex Carbohydrates
Carbs are often categorized by how many sugar units they contain and how quickly they’re digested:
Simple Carbs (digest quickly):
- Monosaccharides: Single sugars like glucose (in rice and potatoes), fructose (in fruit), and galactose (in dairy).
- Disaccharides: Two sugar units linked together, such as sucrose (table sugar), lactose (milk), and maltose (molasses).
Complex Carbs (digest slowly):
- Polysaccharides: Long chains of sugars, including starch (in grains and legumes) and glycogen (in muscle tissue).
- Oligosaccharides: Short chains of 3–10 sugars, often found in beans, onions, and asparagus—these act as prebiotics for gut health.
Where Do Carbs Get Stored?
Once digested, carbohydrates are turned into glucose. Some of that glucose is used right away for energy, while the rest is stored as glycogen in your muscles and liver.
- Liver glycogen helps regulate blood sugar.
- Muscle glycogen is your backup fuel during exercise.
Your body can store about 400–700 grams of glycogen depending on your size, training level, and how many carbs you eat daily.
Fiber: The Carb You Don’t Digest
Fiber is technically a carbohydrate, but your body doesn’t break it down for energy. There are two types:
- Soluble fiber: Dissolves in water and helps with digestion.
- Insoluble fiber: Passes through your gut mostly unchanged and helps with regularity.
You’ll find fiber in fruits, veggies, legumes, and whole grains. It’s key for gut health, blood sugar control, and even satiety.
Why Understanding Carbs Matters for Your Health and Fitness
Understanding how carbs work can help you fuel better, train smarter, and feel more balanced day-to-day. It’s not about cutting carbs, it’s about knowing which ones to choose and when.
Want to know how carbs compare to protein? [Read my blog on protein here.]
FAQ: Carbohydrates and Nutrition
What are carbohydrates and why are they important?
Carbohydrates are a primary energy source for your body and brain. They help fuel everything from workouts to daily tasks.
What’s the difference between simple and complex carbs?
Simple carbs (like sugar and fruit) break down quickly for fast energy. Complex carbs (like oats, legumes, and veggies) digest more slowly and offer longer-lasting fuel.
How are carbohydrates digested?
Digestion starts in your mouth, continues in the stomach and small intestine, and ends with glucose entering your bloodstream or being stored as glycogen.
What is glycogen and why is it important?
Glycogen is stored glucose, mainly in your muscles and liver. It’s your body’s energy reserve during physical activity.
What foods are high in healthy carbohydrates?
Whole grains, fruits, vegetables, legumes, and dairy are all good sources of healthy carbs.
Do I need to avoid carbs to be healthy?
Nope. Carbs are essential for energy and overall health. Focus on whole food sources and balance them with protein and fat.
How do I know which carbs are best for energy and workouts?
Stick with complex carbs like whole grains and legumes for sustained energy. Use simple carbs like fruit for quick energy before or during workouts.
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