What are Carbs?


Carbohydrates are the most abundant molecules on earth. It is also the biggest topic to get through when you’re studying nutrition at school. I feel like 1/2 of my metabolism class was spent on understanding carbohydrates and the other half was left to all the other macro and micronutrients. With all these new anti-carb diets, I feel like the world needs a little refresher or maybe even introduction to the world of carbs to know what you’re missing out on! I’m going to attempt to scale down 2 months worth of grad-level nutrition metabolism class to a few super-relevant paragraphs to help you better understand the wonderful carbohydrate.


1. Molecular Beginnings

In a simplified molecular sense- carbs are molecules with a carbon backbone surrounded by hydrogen and hydroxyl groups with one functional group that tells it how to act within the body or plant it is in. They have many different functions within the body including forming your DNA (the blueprint that tells your body to do everything!) and attaching to cells in your body and telling them what to do. When a bunch of single versions of carbs are linked together they are used for energy storage in the form of starch (in plants) and glycogen (in animals). Carbs also provide structural support in plants in the form of fiber. I won’t say a lot about fiber besides the fact that your body can’t break down fiber for energy, so it’s essentially no calories and runs right through you (in the form of poop!)


2. Primary Energy Source


Because carbohydrates are the #1 energy storage in plants and animals they contain many calories. Calories in the science world just means “energy.” This energy is sooo important because you can’t live without energy in your body. The brain and red blood cells need carbs (in the form of glucose) as an energy source because they cannot use fat or protein as energy at least directly). Which means if your body has no access to carbs you would be brain dead. However, your body is super smart and it is it able to transform protein into carbs (which is the basis for low-carb diets) but this is not optimal for the body.

When you eat foods with carbs, your body begins to store them in a very efficient way (in the form of glycogen), which is intended to be used for later (for if you’re starving or about to run a marathon.) Weight gain happens when you don’t really need energy stores like that. Your body has no way to easily dispose of all this excess energy (aka calories) unless you exercise or decide to starve yourself (insert low-carb diets). If you eat more carbs than you need and don’t dispose of all the excess energy your body starts to form fat deposits to store all this energy.


3. Sources of carbs

We could go on and on about carbohydrates alone and how they work in the body, but the difficult thing about eating them is that they don’t just exist alone. You don’t go to a restaurant and ask for a plate of carbs. There are many carbohydrate rich foods such as bread and fruit, but they coexist within the food with so many other nutrients that you need such as fiber, vitamins, and minerals. The main food groups that are rich in carbs (but also contain many other nutrients) are plants- grains, fruits, and vegetables.

Humans have been able to extract carbs from various plants (corn and sugar cane) to form isolated versions of carbs in the form of table sugar, high fructose corn syrup, etc that we take to make cakes, cookies, and candies. We also refine other plants to make white rice and bread, noodles, and various potato products. When we take whole vegetables and process them we often remove all of the additional nutrients (fiber and vitamins) and leave us with only the energy (or calorie) rich component- the carbohydrates. Fiber also helps keep you feel full and feeds the bacteria in your gut. So when you remove the fiber from plants (whole grain bread vs white bread) you have taken out the component that keep you stay full and are only left all of the calories that could lead to weight. This is why it’s always better to eat a whole fruit or vegetable as a snack compared to say- chips or apple flavored gummies or something.


4. What happens when you don’t eat enough carbs

If you eat less carbs you will lose weight, but if you eat less of anything you will lose weight. When you don’t eat the adequate amount of carbs that your body needs (at least 20 grams per day) your body will start breaking down fat and protein and put you in a state called Ketosis. In this state your brain is being fueled by ketones (the product of breaking down fat and protein) but remember its optimal source of energy is carbs! This means that you may have headaches, nausea, dizziness, and irritability. Also remember that carbohydrates don’t just exist on their own. So a “low-carb” diet” (keto, FODMAPS, Atkins, paleo, etc) actually means low fruit, vegetable, and grain diet. Also remember that these food groups contain vital vitamins and minerals and fiber. If you decide to “cut out carbs” you will mostly likely also be cutting out your source for fiber, vitamins, and minerals, so make sure you’re supplementing these in a healthy way. Remember from the very beginning that the structure of carbs is a bunch of H’s and O’s? Well that’s water! So carbs hold on to a lot of when they’re stored in your body. When you don’t eat as many carbs, your body won’t store as much water which will make it seem like you’re losing a lot more weight than you actually are.

The positive part about all these low carb diets is that they ask you to cut out other major sources of carbs that you don’t need to survive- junk food (cakes, candies, desserts, fries, chips, etc). But you could stop eating that and still eat the other sources of carbs (fruit and grains) and have an overall balanced diet.

If you still want to follow a low carb diet after reading alllllll of this, I would just want you to ask yourself why? Most people go on low-carb diets to lose weight. I’m not denying that you won’t lose weight- the research says that you most definitely will, but what about long-term? Are you going to be able to eat a low carb diet your whole life? Are you saying that if one day you get the opportunity to go Italy you won’t eat all the glorious food just because it’s filled with carbs? Can you find a way to practice life long health with a more balanced diet by listening to your own body which will still allow for the carbs-foods you love? Do you appreciate and celebrate your body for everything that it helps you with every day? Or do you hate your body and punish it by starving it of the nutrients it needs?

What do you think? Is there anything that I got wrong or do you agree?