What’s a carb?
Carbohydrates are one of the most misunderstood components of our diet—and they are a BIG part of our diet to be so misunderstood. You often hear about carbs being “good” or “bad”. The truth is, there really is no “good” or “bad” carb--they can all be used for fuel. The conversation around carbs is really one of timing and quantity.
But let’s start with the basics: What exactly is a carb?
Then we can jump into the whole “good” versus “bad” nonsense by looking at how our body uses carbs.
And we’ll end with how many carbs you need.
What are carbohydrates?
Carbohydrates are one of the major macronutrients we consume in our diet along with proteins and fats. These three elements are necessary for human growth, energy, and development and are the nutrients that we need in large amounts to function appropriately. While all three of these macronutrients can be used for fuel, carbs are the primary energy source for the body. And they are a great source of quick fuel.
Carbohydrates are all just sugar molecules linked together. And they come in various forms like sugar, starch, and fiber. Sugar is the simplest form of carbohydrate. The simplest sugars are a single molecule like glucose or fructose. Other simple sugars are pairs of sugar molecules, for example sucrose (glucose+fructose) or lactose (glucose+galactose). Simple sugars can be found in foods like milk (lactose) and fruit (glucose and fructose) and the obvious places like cokes, cakes, and candy (sucrose).
Other carbs are more complex, like starches. These complex carbs are a bunch of sugar molecules linked together in different ways. You may think of foods like bread, pasta, and potatoes when you think of starch. Interestingly, though, white bread and white pasta are considered “refined” grains, meaning that a lot of the “complexity” is stripped away. Other whole foods like fruits, vegetables, and beans also have complex carbs.
Another category of carbs is known as fibers, which are also made up of multiple sugars linked together. However, your body cannot break down many of the bonds that link sugar together in fiber, so it ends up in our large intestine mostly intact. This provides food for your gut bacteria. That’s is a good thing! Foods high in fiber include vegetables, beans, and whole grains.
You might be wondering why this makes a difference. But the structure of the carbs makes all the difference difference in how your body processes and utilizes the carbs for fuel.
“Good” versus “Bad” Carbs
There is nothing inherently good or bad about a carbohydrate. The key with carbs is determining which are best for you at any moment based on your body, your activity level, and your health and fitness goals. Understanding what your body does with the different types of carbs may be helpful.
Simple sugars or more refined carbohydrates are very quickly digested and absorbed in your blood stream. These are the primary carbs you find in candy, soda, white bread, cookies, sugary cereal, bagels, and fruit juice. In these foods and drinks, the carbs come in a much more simple form, i.e. simple to be broken down to glucose and fructose and absorbed into your bloodstream. These can spike your blood glucose (especially when eaten in isolation) and don’t contribute to long-lasting energy reserves.
If you are engaging in physical activity, this is hugely beneficial. About halfway through the run of a half-Ironman I start reaching for Coca-Cola at the aid stations, which sometimes feels like the only way to get any energy into my tired legs. However, you can imagine that this surge of sugar might not be as beneficial if you are in a marathon of zoom meetings on a Tuesday afternoon. That sugar floods into your bloodstream just the same, but your body has nothing to do with it. It’s all about timing! (It’s also about what you are eating with the carb. But that’s a little outside of the scope of this post.)
When you hear people talk about “good” carbs, they are referring to more complex version of these sugar structures. These are the more complex carbs in whole grains, beans, and many vegetables and fruits. Complex carbohydrates take longer to break down into simple sugars that can be absorbed by the body. This means your glucose levels will stay more stable (and you’ll have more consistent energy) than if you consumed a simple carb, which is digested quickly and subsequently gives you a quick boost of short-lived energy.
In addition, fiber is considered a “good” carb for a bunch of reasons. The coolest (I think) is that it can improve your gut microbiome, which, in turn, can improve your overall health. Fiber is also associated with improved metabolic health, reduced chronic inflammation, and a lower risk of cardiovascular disease. (1)
How many carbs do I need?
How many carbs you need depends on a lot of factors. Your unique body. Your health and fitness goals. Whether you are on a hike or sitting at your desk. Whether eating your mother’s signature peach cobbler is going to bring you joy.
But if you want some actual advice, current recommendations for carbohydrate intake range from 45-65% of your total calories each day. (2) Again, this will vary depending upon how your body works best and your activity level for the day. For example, someone participating in a higher-intensity sport or activity may require a higher quantity of carbs for both performance and recovery, while someone who is sedentary will require less. (3) The USDA also recommends that half of your grains are whole grains and that you get more fiber than most Americans get. (4) I’ll cover those in the coming weeks.
Bottom Line
Carbohydrates are essential for human functioning and energy requirements. They are all just sugar molecules linked together. But the linking differs among carbohydrate sources, which explains what your body does with them. How many carbs you need on any given day will depend on your unique body and your energy needs.
If you are interested in learning more about carbohydrates or how to incorporate them in a way that best aligns with your health goals, let’s chat!
References
1. Barber TM, Kabisch S, Pfeiffer AFH, Weickert MO. The Health Benefits of Dietary Fibre. Nutrients. 2020;12(10):3209. doi:10.3390/nu12103209
2. Slavin J, Carlson J. Carbohydrates1. Adv Nutr. 2014;5(6):760-761. doi:10.3945/an.114.006163
3. Kanter M. High-Quality Carbohydrates and Physical Performance. Nutr Today. 2018;53(1):35-39. doi:10.1097/NT.0000000000000238
4. 2015-2020 Dietary Guidelines | health.gov. Accessed May 12, 2022. https://health.gov/our-work/nutrition-physical-activity/dietary-guidelines/previous-dietary-guidelines/2015
