Medikologia / Macronutrients  / Basic Nutrition 101: Carbohydrates

Basic Nutrition 101: Carbohydrates

Written by: Sarah Brown

When it comes to fat loss carbohydrates are the primary variable in the equation. Diets like paleo or ketogenic manipulate the amount to achieve a particular physiologic response and leverage fat burning hormones. A reverse gear accomplishes the trick as well; with appropriate intake anabolic hormones are activated, helping you build lean tissues and stay healthy. But as the popular saying goes “a tool is only as good as the person using it” applies for dietary strategies too. People have a vague idea how to utilize carbohydrates effectively, and unfortunately out of habit do more harm than good. So to help you get a better understanding of basic nutrition, this article will focus on sugars – also known as carbohydrates. If you’re interested in other macronutrients, feel free to read our articles about protein and fat.

What is a carbohydrate?

A carbohydrate is a molecule found in plants and animals that is also called saccharide or sugar (yes, table sugar is a carbohydrate). However carbohydrate is only a general term. Different types of sugars exist; all classified according to their structure. The simplest is named monosaccharide (mono = one), followed by disaccharides (di = two), then oligosaccharides, and polysaccharides.

Monosaccharides are categorized as simple sugars because the body requires no further breakdown upon digestion. This means once inside the digestive tract, they are readily absorbed and delivered to various cells (brain cells, muscle, or liver). Examples are glucose and fructose (which you’ve probably heard from health experts over and over again).

Disaccharides on the other hand are a combination of two monosaccharides, such as glucose with fructose or glucose with galactose. For example, let’s take the sugar found in milk:

Glucose + Galactose = Lactose

By combining two simple forms, you get Lactose. Ever heard of lactose intolerance and lactose free milk? People affected with it cannot easily digest lactose. So what scientists came up with was to include an enzyme called “lactase” in commercialized milk (if you don’t know what an enzyme is, think of it like an ultra-miniscule biologic specialist that causes changes to molecules) to breakdown the disaccharide into simple sugars, leading to glucose and galactose (one reason why lactose-free milk tastes sweeter than its counterpart).

Oligosacchardies are similar but contain about two to ten simple sugars, whereas polysaccharides greater than 10 molecules. This classifies them as “complex carbohydrates” due to their structural complexity and slow absorption rate.

List of simple and complex carbohydrate sources

Simple SugarsComplex Sugars
Table sugarVegetables
Brown SugarWhole Grain Foods
Corn SyrupPotatoes
HoneySweet potatoes
Fruit JuiceLentils
Soft drinksBeans


Why Your Body Needs It

Every cell of your body runs on glucose for energy, especially brain and muscles. When supply decreases such as skipping a meal the liver (a sugar storehouse) releases glucose (stored as glycogen) in the bloodstream to keep a normal level in the blood. In addition, muscles are full of glycogen too. Therefore, the liver and muscles are two important sites of energy storage.

Okay, let’s pause for a moment and have a reality check.

You eat dinner around 8pm. The meal contains moderate amount of carbohydrates and protein. The body absorbs it, and glycogen synthesis (a fancy term of saying “sugar is created”) begins. Few hours later, the process stops. So the liver releases glucose for the next 8-12 hours to provide fuel. Once liver glycogen is depleted (assuming you’re fasting throughout the day), muscle glycogen is the next source for the next few hours. Ever felt tired and grumpy after skipping a meal? That’s a sign of glycogen depletion, and a signal for the next meal.


Refined vs. Complex

Stepping out for a second and looking at the big picture you’ll see that carbohydrates are classified as simple (monosaccharide) or complex (i.e. polysaccharide). Simple sources include white bread, white rice, sugar, high fructose corn syrup, or white pasta; whereas complex ones are found in legumes, potatoes, yams, sweet potatoes, or anything straight from nature. A rule of thumb to differentiate between the two is the whiter the food, the more refined it is (except for white beans), and the less processed (i.e. brown rice vs. white rice), the more complex and healthier.

Now, you’ve probably heard that refined sugar is unhealthy, why is it?

Because it lacks fiber.

One of the perks of complex carbs is their fiber content (a complex sugar that cannot be entirely digested), which acts as a buffer for glucose release in the blood. Think of it like a string (fiber) where small molecules of sugars are attached. When this structure enters the body, your gastrointestinal tract will take longer to break down its components due to the myriads of bonds. Each enzyme has to detach the molecules one by one, therefore slowing their release. In addition, fiber acts like a natural broom. Its indigestibility allows it to travel throughout the tract and absorb dirty stuff while providing food for your micro flora (yes, fiber is considered a PRE-biotic, meaning – it provides nourishment to your gut bacteria, the good guys). Hence, eating unprocessed carbs slows down sugar release, ultimately reducing the impact to the pancreas and diminishing the risk for future diabetes. In addition, fiber is well established to prevent colon cancer.

In contrast refined sugars lack fiber. This causes a faster release of glucose in the blood, forcing a faster release of insulin (a traffic enforcer responsible for redirecting sugar to their proper place) by the pancreas, predisposing you to metabolic disease.

So how do you eat carbohydrates without sacrificing health and waist line?

Stick to whole foods. That’s the short answer.

By avoiding as much as refined sugars as possible, it’ll be easier to maintain or lose weight while dieting because whole foods satiate you more; ever heard that potatoes “stick to your ribs”? That pretty much sums the importance of complex carbs. In fact, it’s almost impossible to gain weight, especially with plenty of vegetables. But does it mean you should completely avoid your favorite food? Not really. As long as you keep eating healthy 80% of the week, you’re free to have 1-2 cheat meals.


How Many Carbs Do You Need Daily?

Amount of carbohydrates depend on different factors. For instance, diabetic individuals are advised to decrease the amount of dietary sugar, while endurance athletes need high amounts of carbs to refill glycogen daily; whereas some of us (majority of the population, for that matter) fall in between. So assuming you’re the average Joe who sits on a chair all day, 100 grams and above is a good place to start. This will prevent the body from turning into a ketogenic state, and supply appropriate amounts of energy for your brain. How much is 100 grams you may ask? If we’re going to guesstimate portions for practical purposes – 1 cup of cooked rice, 300 grams of raw potatoes, or 1 cup of dry oats is between 45-50 grams of sugars, give or take. Eat twice the serving a day and you’ve reached the required intake.


Key Points to Remember:

-Carbohydrate is a general term, but it’s also known as sugar or saccharide.
-There are 4 types of carbohydrates: monosaccharide, disaccharide, oligosaccharide, and polysaccharide.
-Carbs can also be classified into two: simple (processed) and complex. Simple ones are white (except white beans) and mostly unhealthy. Complex ones are healthier and heavier to digest.
-Unprocessed sugars help you decrease the risk of diabetes and colon cancer.
-The amount of carbohydrates depends on different factors. But for the average person 100 grams a day is the minimum.



1.Bender, D. A., & Mayes, P. A. (2012). Carbohydrates of Physiologic Significance. In R. K. Murray et al., Harper’s Illustrated Biochemistry (p. 132). United States: McGraw-Hill Companies, Inc.

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