We’re continuing our Nutrition 101 Mini Series with everything you need to know about carbohydrates. March is National Nutrition Month, and this guide will help you separate fact from fiction about this important macronutrient.
If you missed Part 1 about protein, you can find it linked below. Today we’ll cover: what carbohydrates are, what they do in the body, how much you might need, where to find them, the difference between simple and complex carbs, the role of fiber, health benefits, and a few carbohydrate-rich recipes to try.
Carbohydrates are one of the most discussed—and often misunderstood—food groups. Media headlines and diet trends sometimes demonize carbs, but many carbohydrate-containing foods are nutritious and important for daily energy and overall health.
What are carbohydrates?
Carbohydrates are one of three macronutrients, alongside protein and fat. They range from simple sugars (glucose, fructose) to complex molecules such as starches and dietary fibers. When digested, most carbohydrates are broken down into glucose, which the body uses as a primary energy source for cells, especially the brain and red blood cells.
How do carbohydrates function in the body?
Carbohydrates supply energy at about 4 calories per gram, the same as protein. After digestion, glucose travels through the bloodstream to cells for immediate use. Some glucose is stored as glycogen in the liver and muscles for short-term energy reserves. Once glycogen stores are full, excess carbohydrates can be converted to fat. That said, carbohydrates alone do not inherently cause weight gain—consuming more calories than you expend, from any macronutrient, leads to fat gain.
How many carbohydrates do you need?
There is no single universal requirement for carbs; needs vary by body size, activity level, and health goals. Dietary guidelines commonly recommend that 45–65% of daily calories come from carbohydrates as a general range. Very low- and very high-carbohydrate diets have both been associated with different health outcomes in research, so a moderate approach is safe for most people.
Rather than obsessively counting grams, a practical approach is to balance your plate: aim for half the plate filled with non-starchy vegetables, about a quarter with whole, high-fiber starchy carbohydrates, and the remaining quarter with protein and healthy fats. Prioritize whole, minimally processed carbohydrate sources to support sustained energy and satiety.
Where do carbohydrates come from?
Carbohydrates are present in many foods, including some you might not expect:
- Table sugar, syrups, candy
- Soda and sweetened beverages
- Bread and grains (wheat, barley, oats, farro)
- Dairy products like milk and yogurt
- Beans, lentils, and legumes
- Fruit
- Starchy vegetables such as potatoes, corn, and peas
- Non-starchy vegetables like leafy greens, tomatoes, carrots, and peppers
Simple vs. complex carbohydrates
Simple carbohydrates are broken down and absorbed quickly, producing a faster rise in blood sugar. Examples include table sugar, many sweets, fruit sugars, and some refined grains. Complex carbohydrates take longer to digest and generally produce a slower, steadier blood sugar response; they include whole grains, starchy vegetables, and fibrous plant foods.
Many whole foods contain a mix of carbohydrate types—for instance, beans provide starch, fiber, and plant-based protein—so focusing on whole, minimally processed options is more useful than labeling foods strictly “good” or “bad.”
What is fiber and why does it matter?
Fiber is a non-digestible form of carbohydrate found in whole grains, vegetables, fruits, legumes, nuts, and seeds. It cannot be fully digested in the small intestine, so it reaches the colon where it supports beneficial gut bacteria and contributes to stool bulk.
Soluble fiber absorbs water and forms a gel-like substance in the gut. It helps moderate blood sugar spikes and can lower blood cholesterol. Oats, beans, apples, and the soft flesh of many fruits are good sources.
Insoluble fiber adds bulk and helps maintain regular bowel movements, preventing constipation. Whole grains, vegetable skins, and many raw vegetables provide insoluble fiber.
Both types of fiber slow digestion, increase satiety, support gut health, and are linked with lower risk of chronic disease. Increasing fiber-rich foods—non-starchy vegetables, whole grains, legumes, fruit, nuts, and seeds—supports digestion, weight management, and overall health.
Health benefits of carbohydrates
When you choose nutrient-dense carbohydrate sources, they contribute to many aspects of health:
- Provide steady energy for daily activities and exercise
- Support healthy blood sugar regulation
- Help lower cholesterol when high-fiber foods are consumed
- Promote gut health through fermentation of fiber by beneficial bacteria
- Reduce cravings and help maintain a healthy weight when part of balanced meals
- Support mood and sleep by providing consistent energy to the brain
Why do people follow low-carb diets?
Low-carb diets can produce rapid short-term weight loss for several reasons: reducing overall calorie intake, removing many processed and high-calorie foods, and initial loss of glycogen-bound water. However, strict long-term elimination of carbohydrates can be hard to sustain and may unnecessarily restrict nutritious foods. For most people, a balanced approach that emphasizes whole, fiber-rich carbohydrates alongside protein and healthy fats is more sustainable and beneficial for long-term health.
If you’ve avoided starchy carbohydrates, try reintroducing high-fiber options such as whole grains, legumes, and starchy vegetables and notice how your energy, mood, and digestion respond. Many people feel brighter, more energized, and more regular after adding these foods back into their routine.
Carbohydrate-Rich Recipes
Banana Bread Overnight Oats
Oats are rich in soluble fiber, making them an excellent choice for a filling, nutritious breakfast.
Black Bean Brownies
Black beans add fiber, starch, plant protein, and important nutrients to a satisfyingly fudgy treat.
Spinach, Apple, and Lentil Salad
Leafy greens, fruit, and lentils offer a mix of fiber, vitamins, and complex carbohydrates for a balanced meal.
Questions or comments? Did you find this guide helpful? I’d love to hear from you.
Stay tuned for Part 3 of the Nutrition 101 Mini Series, all about fats!
XO
Catch up with the Nutrition 101 Mini Series
Part 1: What You Need to Know About PROTEIN