Carbs, what are they good for?

Nutrition basics: Carbs – short for carbohydrates
different types of italian macaroni
Photo by Klaus Nielsen on

So, what are carbs good for? What even are carbs?

What are carbs good for?

Carbohydrates, or carbs, are a main source of energy for the body.

Carbohydrates are one of three macronutrients (carbohydrates, protein, and fats), that our bodies break down into energy. This energy is what we measure with calories. So along with protein and fats, carbohydrates are where we get calories to use for energy.

Carbohydrates are the main source of energy for the brain, most of the time.

Carbohydrates are the quickest available form of energy

Carbohydrates, stored in our muscles in the form of glycogen, are an easily available energy source during exercise

Carbohydrates that are not used for energy can be stored as fat for later use.

Different types of carbohydrates break down at different rates and so can give us energy at different speeds

Some carbohydrates act as food for the bacteria that live in our digestive system. Choosing certain types of carbohydrates over others helps keep these bacteria (and us) healthier.

What even are carbohydrates?


[This explanation is for the science nerds. Skip ahead if you want more practical definitions]

Carbohydrates are combinations of carbon, hydrogen, and oxygen molecules in the ratio of 1:2:1 (carbon + H2O/water/hydro=carbohydrate for you word nerds).

We get energy from these molecules when they go through a process called cellular respiration (which nutrition students spend A LOT of time memorizing for how little we use it in day to day nutrition practice). This process requires oxygen and produces energy, carbon dioxide, and water. This one of the main reasons we breathe in oxygen and breathe out carbon dioxide and water by the way.

hand illustrated guide showin interaction between photosynthesis, cellular respiration
Drawn by me as a student. I’m proud enough of this study aid that it’s been on my office wall for years.


The carbohydrates we eat come in three forms: sugars, starches, and fibers.

Sugars can come in naturally occurring forms like in fruit, milk (lactose), vegetables, honey, grains, etc. They can can also be refined and added to foods (white sugar, brown sugar, corn syrup, agave, etc.). This is the quickest to digest form of energy.

There are lots of types of starches but these are the carbohydrates we mainly get from foods like grains, starchy veggies (potato, corn, cassava, sweet potato), seeds, legumes. These can be in the form of breads, pastries, cereals, porridges, noodles, doughs – carbohydrates and starches are very versatile!

Fiber is a mostly indigestible carbohydrate that we actually don’t break down well into energy, but gives us lots of other health benefits (including feeding good bacteria in the digestive system). Lots of foods have fiber, including fruits, veggies, whole grains, nuts, seeds, legumes, and beans.

chocolate cereal on white bowl near glass of milk
Photo by Pixabay on – Many of us think of high fiber cereals or bran but fiber is present in many foods!

Many foods that contain carbohydrates contain a combination of sugar, starch and/or fiber.

When people in general talk about carbs, they often mean different things. Some people just mean bread or pastries. Other people mean foods made with flour: bread, pasta, crackers, cereal. Some people mean all starchy foods and sweets: bread, rice, potatoes, tortillas, cookies. Some people mean any foods that contain any significant amount of carbohydrates at all – they include fruits and many veggies in this list (especially common when following a keto diet)

When dietitians talk about carbohydrates, we usually just mean a category of foods that are rich in carbohydrates. Usually this means: fruits, milk, starchy foods, sweets, sweet drinks, etc. But it is always a good idea to clarify. Most of us aren’t talking about molecules when we talk about what we eat.

I always have to be careful when I am speaking with a client about carbs that we are thinking of them same foods. If not, that’s ok – we just need to make sure we have the same understanding.

Are carbs bad?

No. See: what are carbs good for?

Are there a wide variety of carbohydrate foods with a wide variety of nutritional benefits and/or lack of benefits?

Yes. A can of Coke is very different than an apple is very different than a loaf of sourdough is very different from a pot of beans. All of these foods provide carbohydrates.

Do I need to restrict carbs? How much carbs should I eat?

This is a great question to discuss with a dietitian who can go over your individual needs with you. They can also determine if there are specific types of carbohydrate-rich foods that might be a better fit for you than others. There are many different diet patterns as far as carbohydrates go that are healthy options – telling you what pattern is right for you is NOT within the scope of this article.

TL;DR on Carbohydrates:

  • Carbohydrates are good for energy and to feed our gut bacteria
  • Carbohydrates come in three forms: sugar, starches, and fiber
  • There are a variety of foods rich in carbohydrates such as fruits, vegetables, milk, nuts, seeds, legumes, grains. Different foods have different benefits and effects on the body
  • Talk to a dietitian if you need help figuring out how much carbohydrate or what type of carbohydrate you need.

If you’ve made it to the end of this article, here’s a reward. Crabohydrates is a common typo for me, so I finally illustrated it.

various carbohydrates but drawn as if they were crabs. (orange crab, crusty bread crab, cupcake hermit crab, ugly potater crab, le petit crabe croissant, tiny grain of rice crab)

This post is intended to be informational only and is not medical or nutritional advice. If you have questions about your unique needs, ask about a custom meal plan or speak with a registered dietitian-nutritionist near you.