Between the macros there’s a lot up for debate, leaving many of us confused as to the function of carbohydrates, fats and proteins in our bodies.
Generally speaking, we’ve been told that many carbs are a no-go if you want to lose weight, gain muscle, or you know, get the healthiest, most nutrient dense diet possible.
But let’s be real, how many of you know the ins and outs of the humble carb? Like how carbohydrates function, carbohydrates food sources and how they affect our bodies?
Let’s stop making assumptions and dive deep into the nitty gritty. Here’s a look at what makes a carb a carb, when you should avoid them, and when to keep ‘em around.
Use this table of contents to skip to whatever section you’re looking for:
The Background on Carbs
Carbs have a wide-ranging scope of physical effects (both positive and negative). But before we delve into that, let’s break things down a little…
What are Carbohydrates?
Well, a carb is a macronutrient—a sugar, starch or fiber found in grains, fruits, vegetables, and dairy products. They’re hard to avoid and they’re one of the most basic food groups humans need to stay alive.
Basically, carbs get their name from their chemical makeup—containing carbon, hydrogen, and oxygen. Once we eat a carb, our bodies convert it into glucose (one of our body’s primary energy reserves) —which is transported to our cells via insulin. Once there, they’re able to execute…
The Main Function of Carbohydrates
The main function of carbohydrates is to provide fuel for the nervous system and keep muscles on the move.
Which sounds simple, but it’s an extremely complicated process that involves almost every system of the body. We’ll delve into this more below. There are 3 types of carbohydrates…
The 3 Types of Carbohydrates:
Carbs can be found in just about everything we eat, but not all carbs are the same. Here’s a quick breakdown of where are carbohydrates found:
A complex carbohydrate, found in vegetables, grains, and beans. Starchy foods, while often maligned, provide the body with key nutrients like iron, calcium and B complex vitamins. But, going overboard on the potatoes, rice, and breads can lead to the dreaded food coma or make you feel sleepy after eating.
While sugar is relatively familiar, the definition of this type of carb is more expansive than the white stuff you put in your tea…
So, what is sugar? Sugar, can be classified as any number of sweet, colorless, water-soluble compounds. Sugars are found in fruits, vegetables, milk and more—making up the simplest group of carbs—easily identified by the “-ose” suffix they carry around.
Sucrose (or table sugar) is the most common type—found in soft drinks and processed foods. Other sugars include fructose, which comes from fruit and lactose, which comes from milk.
Fiber also falls into the complex carbohydrate category. Fiber isn’t digested by the body—passing through the stomach, mostly intact. While this sounds a bit strange, it’s worth pointing out that fiber keeps you full, regular, and satisfied after eating.
These healthy carbs can be found in fruits, vegetables, whole grains, and cooked dry beans/peas. Beyond digestive health, fiber may have a positive effect on cholesterol.
Good Carbs vs Bad Carbs. Different Examples of Carbs and How They Function
Most scientists agree that not all calories, or more specifically, carbohydrates are created equal—specifically because different types of carbohydrates function differently in our bodies (source) —Some filling us with the nutrients, while others may lead to common health issues.
Here’s another means of categorizing carbohydrate foods: based on their chemical structure:
To put it simply, simple carbs are made from just one or two sugar molecules. Simple carbs include glucose, sucrose, fructose, and lactose.
Now, while simple carbs are often considered the bad guys, the truth is a little more nuanced than that. Simple carbs found in fruit or dairy products are considered healthy for most people (in moderation), while foods containing processed or refined sugars such as table sugar (sucrose) are not exactly the best choice. To understand the function of simple carbohydrates, may not be ideal.
Complex carbs also contain sugar molecules but are present in the form of long chains (3 or more). Which means, these carbs take longer for the body to digest and absorb.
These are often referred to as “good” carbs, and include items like beans, peas, whole grains, and fiber-rich fruits/vegetables. In addition, these foods contain many essential nutrients like fiber, vitamins, and minerals.
Complex carbs may also be refined. Which means the high fiber parts of the grain are removed–think white bread, potato chips, and baked goods. The refining process “simplifies” the carb, stripping it of its health benefits.
When it comes to carbohydrates, luckily, it’s pretty easy to tell the good from the bad.
However, you can’t look at a list of carbohydrates, and categorize them as the traditional good vs bad, per se—rather refined vs. natural.
Per Medline, most carbs should come from complex carbs and naturally occurring sugars (found in milk, fruit and veggies).
What Do Carbohydrates Do? A Look at the Function of Carbohydrates in The Body
Seeing as carbohydrates are one of the 3 macronutrients needed by our bodies, they’re in charge of many basic functions. To name a few function of carbohydrates:
Blood sugar and insulin
Eating carbohydrates is a quick way to increases blood sugar and stimulate insulin production—but is this a good thing? How does insulin work? And what is blood sugar?
It’s relatively simple: You eat carbs which are broken down by your digestive tract into simple sugars. These are absorbed into the bloodstream as glucose i.e. blood sugar.
Glucose gets transported to the body’s cells via insulin—a hormone made in the pancreas—which is then used by our cells as fuel (source). Once glucose is moved out of the bloodstream and into the cells, our blood sugar levels go back down (source).
Sounds great, but, this system doesn’t run smoothly for everyone, and for those people, controlling blood sugar is a regimented and arduous task.
The first scenario in which this system doesn’t run smoothly is seen in people with a…
1. Lack of insulin responsive cells or production (source)—which leaves glucose and insulin levels at a heightened level after eating. Overtime, this high demand on insulin producing cells can wear them out to the point of preventing further insulin production.
This is where insulin resistance, type 2 diabetes, heart disease, weight gain and other blood sugar/insulin perpetuated maladies arise.
2. On the other hand, hypoglycemia, or low blood sugar is the result of blood sugar dropping too low. This can happen if your body uses glucose too quickly, or it’s released into the blood stream slowly/not at all (source)—hypoglycemia is rare in non-diabetic patients (source).
Which leads us to the autoimmune disease with a similar blood sugar response: Type 1 Diabetes, in which the pancreas produces little to no insulin (source).
Healthy blood sugar and insulin levels are key to maintaining a healthy body. Whether you have a health issue related to regulating your blood sugar or not, it’s important to understand the foods that can spike glucose levels.
Scientists are continually finding more evidence centered around maintaining health blood sugar levels and the wide range of effects it has on our bodies—from mental to physical health.
Carbohydrates function in energy production by supplyingd our bodies with 4 easily digestible calories (energy in food) per gram, making them our body’s main source of energy (source)—that said, they’re not the only source of energy, but that’s a convo for another article.
We already touched on insulin and glucose/blood sugar regulation above—from this process, whatever glucose isn’t immediately used for energy is sent to the liver or muscles in the way of glycogen for later use, or is stored as fat (source).
Simple carbs are used quickly as an energy source because their minimal molecular structure is easy for the body to break down. This means a quick spike in energy, followed by, sadly, a vengeful crash.
On the other hand, complex carbs are made of multiple sugar molecules—which takes more time for the body to break down into energy, therefore your blood sugar won’t go through such highs and lows.
Triggers appetite, hunger and fullness
A study conducted on the moods of grumpy people reaching for an afternoon snack found that carbohydrates increased their brain’s productions of serotonin more than other food groups (source)—consuming protein, unfortunately, didn’t have the same effect.
Serotonin is known as the “feel good hormone”. Once activated in the brain, it works to stimulate sleep, regulate blood pressure, control your mood, appetite and your sensitivity to pain.
Which sounds totally great—but there are some drawbacks…
Because of serotonin’s ability to control your mood, many people lean on the overconsumption of carbohydrates to feel better—essentially using this food group as a drug (source). Hence the term “carboholics”.
As if that wasn’t enough, our bodies have another set of hormones known as the “hunger hormones”—ghrelin and leptin. Ghrelin is the hormone that makes you feel hungry, while leptin suppresses your appetite.
This study evaluated ghrelin and leptin levels after patients consumed various meals—each high in either protein, fat or carbs.
The result of the high carb meal? At first, ghrelin levels were strongly suppressed—then they rebounded, with a vengeance—making subjects hungrier than they were prior to eating—scientists then concluded that consuming carbs can make you hungry, and crave carbs again…
…which explains why many of us have a hard time calling it after just one cookie.
Side note, and a topic for another article—the study found that protein was the best suppressor of ghrelin (source).
We already discussed serotonin, but here’s a little more on carbohydrate’s effect on our mood…
Serotonin is made in the brain, where it performs its main functions (source). The production of serotonin is stimulated by a handful of nutrients combined with serotonin’s precursor tryptophan—an essential amino acid (meaning the body can’t make its own and it must come from diet) (source).
Foods high in tryptophan are protein-rich foods, such as meat, dairy fruit and seeds (source). So, where do tryptophan-lacking carbohydrates come into play?
Our brains are protected from the passage of certain substances by a filtration process called the blood-brain barrier. As you can imagine, there’s constant competition for amino acids to pass this barrier, making it difficult for tryptophan to get through. But, when you consume carbs, insulin is secreted, which works to decrease the level of competing amino acids in the blood, making way for the tryptophan to cross the barrier (source).
Ergo, consuming carbohydrates helps facilitate the transport of serotonin’s precursor tryptophan to the brain.
This has led to a few opinions on carbohydrate’s effect on our moods…
1. One side is carb consumption is directly correlated to good moods:
MIT researcher Dr. Wurtman suggested that when you stop eating carbs, your brain stops regulating serotonin—and carb consumption is the only natural means of stimulating production of this hormone. She continues to say that…
“a meal like pasta or a snack of graham crackers will allow the brain to make serotonin, but eating chicken and potatoes or snacking on beef jerky will actually prevent serotonin from being made” (source).
To me, this is outdated research, and I tend to agree more with recent studies that show…
2. Consuming the right carbs is necessary for mental health, and sugar can negatively affect your mood.
We already know that not all carbs are created equal—and a growing body of research suggests a strong link between diets high in refined carb and depression. To name a few:
1. This study conducted over a span of 22 years found that men who consumed 67 grams of sugar or more daily were 23% more likely to be diagnosed with depression.
2. Per this study, depression in postmenopausal women may be directly links to diets high in refined carbohydrates.
Fiber—a carbohydrate found in fruit, vegetables, whole grains and legumes—is essential for healthy digestion.
There are two types of fiber, soluble and insoluble, both of which are in most plant-based foods—ergo, eating a variety of high-fiber foods will help you receive the most health benefits (source).
Fiber is known as the bulk that moves everything through our digestive tracks—because, unlike proteins, fats and other carbohydrates, it’s indigestible and passes through our systems mostly intact—adding roughage to your bowels while keeping you full, regular, and satisfied after eating.
That said, as you know from the above, not all carbohydrates are fiber. There are also sugars and starches…
…And studies show that diets high in refined sugar have a slower digestion, due to the effects refined sugars have on our gut bacteria.
Prebiotics and Colon Health
On top of fiber and its significant role in our digestive health, carbohydrates bring another group of beneficial foods to the table…
Prebiotics are nondigestible carbohydrates that stimulate the growth or activity of bacteria in the colon. This ultimately improves digestive health. Unfortunately, current research on this group of foods is limited, it’s been suggested that they may:
- Reduce symptoms of IBS
- Protect against colon cancer
- Enhance uptake of certain minerals
- Lower some risk factors of cardiovascular disease
All prebiotics are fiber, but not all fibers are prebiotic—Looks for them in foods such as leeks, asparagus, and chicory.
The brain and its abundance of nerve cells, demand more energy than any other organ. In fact, they require half the glucose in our bodies! (source)
Which leads many of us to believe that when the body lacks an adequate amount of glucose, the brain and its functions (thinking, learning and memory) are affected.
But, that’s not necessarily true…
Studies have shown that people with an increased level of ketones in the body—experienced by low carb dieters who switch from using sugar as a main source of energy to fat—may have positive effects on memory and neuro function.
In addition, many low carb meal plans tend to be high in healthy fats such as omega 3s—which play a crucial role in brain functionality
Another controversial subject in the way of carbohydrates is the affect they may or may not have on our weight.
On one side, we’ve got fiber. Fiber is considered an important tool for weight management as it fills you up, and keeps you satiated.
What’s more, a study published in the Annals of Internal Medicine examined 240 patients with metabolic syndrome and found that those who simply increased their intake of fiber were able to lose more weight.
That said, fiber isn’t the only type of carbohydrate…
The other side of the argument is that reducing carb intake is the fastest way to stabilize glucose and insulin levels—which raised levels of insulin can program the body to gain weight (source).
As mentioned above, when we eat more carbs than our cells require for immediate energy, they’re stored as glycogen or as fat. That said, building these reserves without expenditure leads to excess weight.
Finally, increasing total carbs means increasing total calories. Calories in, calories out—traditional wisdom applies.
How Carbohydrates Function…
How Carbohydrates Function When You Eat Too Many
Carbohydrate examples are most typically linked to cookies, cakes, late night pizza binges, you know, basically anything that can derail a diet and send you into a food coma.
So, it should come as no surprise that hitting the carbs too hard can lead to some pretty serious health effects. Here are the potential affects, more information above:
- Spike in blood sugar and insulin levels
- Food comma
- Triggers appetite
- Carb consumption as a means of comfort
- Refined sugar and slowed digestion
- Potential weight gain
- Negative effects to cognitive health
How Carbohydrates Function On a Low Carb Diet
There are several reasons to limit your carbohydrate foods intake — here are some of the potential benefits you’ll see when you stick to low carb meals:
- Easier to regulate blood sugar and insulin
- Increased energy, after the initial “hump”
- Keeps you full longer
- Potential weight loss
- Improved cognitive health
- Less cravings
And while there’s a whole slew of terrifying bodily functions taking place after going on a full-fledged carbohydrate foods binge, there are some risks—or rather, unpleasant effects that can take place.
Fearing carbs uniformly goes against the wisdom of the good old “five-a-day” advice—leaving out veggies and fruits that provide key nutrients like vitamins, minerals, fiber, and antioxidants. A deficiency in carbohydrates can lead to:
- Not So Fresh: The bad news about relying primarily on fat and protein? The lack of carbs builds up ketones, which can cause bad breath. If you’re planning to go super low carb, stay fresh by incorporating plenty of sugar free gum.
- You’re constipated: Another issue with losing the carbs is, losing the critical fiber that goes along with it. And with fiber comes, well, regularity. Keep your system running smoothly by making sure you’re getting enough vegetables, fruits, and whole grains.
- You’re Wiped Out: While a low carb diet can get rid of those nasty sugar highs and lows, no carbs means no energy in a lot of cases. If you’re feeling sluggish, it may be time to reevaluate your fruit and vegetable intake. You may also be experiencing the carb flu, which is your body transitioning from sugar as an energy source to fat—which typically lasts about a week.
How to Maximize the Function of Carbohydrates
Beyond the carbohydrates definition that divides the two into simple and complex, there are a few other ways you can capitalize on the benefits of this macronutrient…
1. Eat Healthy Carbs
At this point of the article, this may seem like a giant “duh”, but it’s worth mentioning. To maximize the benefits of carbs in your diet, eat the right ones.
2. What Are Macronutrients and How to Balance:
The three macronutrients I’m referring to are: carbs, proteins and fats.
We’ve gone over the function of carbohydrates, but they rely on other nutrients to help maximize their potential.
What is the Function of Fats: Fats essentially provide a backup energy source for your body to use when carbs aren’t available—which is why low carb diets are linked to weight loss. Fats help maintain your body temperature and absorb nutrients.
What is the Function of Lipids: The function of lipids in the body is diverse, but these compounds play a role in energy storage and provide energy needed for a number of internal processes. The main function of lipids is to power our muscles.
What is the Function of Proteins: Proteins are present in every cell of your being, from your fingernails to your skin and organs. The main function of proteins is to regulate processes in the body, like breaking down food and transporting materials throughout the system.
3. Rethinking/How to Quit Sugar
Because the carbs in sugar are simple, it’s safe to say, breaking up with sugar could be a good move for your health. But there’s more to it than cutting out notorious sugar foods like candies, cakes, and pints of ice cream.
A few steps for making the change:
1. Start by cutting out things like soft drinks and added sugar in your coffee and tea, and go from there.
2. Read food labels! Look out for things like evaporated cane juice, corn syrup, sucrose, dextrose, fruit juice concentrate, and more.
3. Eat whole foods—packaged tomato sauces, condiments, salad dressings, and store-bought baked goods are often packed with the sugar. Go for plain vegetables, whole grains like brown rice and quinoa, and unseasoned meats. Seasoning yourself can lead to more health-conscious decisions.
4. Skip the juice—fruits are loaded with sugar, but also are rich in fiber. Eaten whole, fruit sugars are not a problem for most people (in moderation of course).
While a low or no sugar diet can be hard to get used to, finding a meal plan that works for you is crucial. For more tips on ditching simple carbs, here are some of our favorite low carb recipes.
4. Look at Net Carbs
If you’d like to try a low carb diet, but are worried about some of these effects, focus more on net carbs. Net carbs are the grams of total carbs in any given food, minus the total grams of fiber. The thought here is that you only consider the difference as part of your overall carb intake.
The Function of Carbohydrates and What’s Right For You?
Now that you know the function of carbohydrates, it’s up to you to decide what your body needs.
Whether you’re diabetic, overweight, or looking to amp up your workout routine, a keto foods lifestyle might be a good fit—but it’s worth mentioning that balance is the key to your success—we might sound like a broken record, but diverse nutrients are the only way to go.
For others, it might be worthwhile to cut back on simple carbs and focus on getting the five-a-day fruits and veg from whole food sources. Everyone’s body is different and requires a different balance to function properly.
Have you ever tried a low carb diet? If so, let us know what your experience was like, or feel free to share any favorite recipes or food hacks.
Note from the Author:
When I started writing this article, it was a huge struggle. I thought of a function a positive trait—and man, have I been mad at carbs lately. No, I’m not entirely anti-carb, but I’m also not their number one fan.
With my recent life changes—all of which are centered around this one macronutrient—I’ve spent late nights browsing PubMed, talking to doctors, and reading everything I can find about carbs…
…And the most important lesson I’ve learned after all this research is this: whether you simply want to know what carbs do (and you’re currently snacking on a plate of cookies) or you haven’t touched a sugar/starch in years, there is not one simple answer for every person.
Figure out your body, what works best for you, and what you need to function. I know a low carb diet is how I need to eat, and as a diabetic who’s been sick most of her life, it’s worth sticking to this lifestyle to remain a much healthier and happier person!
That said, I bring to you a collaboration of my research on carbohydrates, can’t wait to hear from you, let us know in the comments below what brought you here.