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.