May 2019 Update: Since I officially passed the 1 year anniversary of my new website and blog, I’ve been digging through some of my earliest posts and giving them a little update. Carbohydrates have continued to be a consistently hot topic since I originally wrote about them last year, so I decided to revisit the great carb debate!
I also want to apologize for the gap in blog articles! This spring really tested my limits of how full my cup can be before things start to spill over. I had a number of speaking engagements, a Dietetic Intern to supervise for 6 weeks, and my Certified Diabetes Educator renewal exam to complete over the weekend. Things have been a little crazy these past few months! Fortunately now all of my big projects are completed and I’m ready to get back into blogging (and enjoying the heck out of my summer!)
Despite carbohydrates being a consistent topic of much online debate with the re-rise in popularity of low-carb and extreme no-carb eating, there still seems to be a bit of misunderstanding about what this macronutrient is all about. Some people claim that carbohydrate intake is absolutely essential to proper body functioning, yet others insist that the recommendations for dietary carbohydrates are a bunch of BS, and that the human requirement for dietary carbohydrates is ZERO. So what gives? How can a substance be both essential for good health yet completely unnecessary at the exact same time?
As with most things on the internet that are hotly debated, the right answer is always somewhere in the middle…
But first, a quick review: What exactly is a carbohydrate? What are the different types of carbohydrates that we find in our food, and what are the different effects they have on our bodies? Then I’ll get down to the nitty gritty and answer the most important carb questions like “will eating carbs cause me to gain weight?”, or “does eating carbohydrates cause diabetes?”, and most importantly “Is it all about the insulin?”
So, Let’s dive in!
A Quick Carb Overview
Carbohydrates = Sugar…Literally
The term “carbohydrate” is simply the chemical term for sugar. They are molecules made of various combinations of Carbon, Hydrogen, and Oxygen which our bodies are able to break down for energy. All of the cells in our bodies prefer carbohydrates as their primary energy source. Carbohydrate is a huge umbrella term that encompasses ALL the different types of sugars out there. Within the category of carbohydrates there are 3 main groups. Simple Sugars, Complex Carbohydrates (aka Starches), and Fibre.
For example, here is how glucose is structured… This is the simplest form of sugar, called a monosaccharide. That means it’s just a single sugar molecule (mono = one). This is the type of sugar our cells use for energy and is what our blood sugar (blood glucose) is made of.
Simple Sugars are just that…simple structures made up of only 1 or 2 sugar molecules. The single sugars (monosaccharides) are Glucose, Fructose, and Galactose. The various combinations of 2-sugar molecules (disaccharides) are made from these. Simple sugars are found in foods that tend to taste sweet such as fruit, white sugar, brown sugar, milk, honey, agave nectar, syrups, etc. These types of sugars are very quickly broken down and absorbed by our bodies for energy because the lack of complexity in the structure means our bodies have to do very little work in order to digest and absorb them.
Complex carbohydrates, or starches, are larger, longer chains of these simple sugars bonded together (polysaccharides). They vary by their look and structure but the main components are the same. These types of carbohydrates take a bit longer for our bodies to break down because our digestive enzymes produced in our gastrointestinal tract need to break every single bond in the chain before the individual sugar molecules can enter our blood stream. This is why starches/complex carbohydrates don’t taste as sweet to us, and can keep us feeling full for longer after eating them than say, a sugary beverage.
This is the structure of a starch molecule
What’s important to note however, is that all of these types of sugars and starches are digested and absorbed by our bodies by the SAME mechanisms. Sugar is sugar is sugar. We use the same enzymes and transporters to digest bread, fruit, white sugar, milk, and all of the other hundreds of food items that contain carbohydrates. Once they’re in our gut, our bodies treat them all equally. But despite that, we know that some types of carbohydrate foods are better for our health than others (for example we can probably all agree that pop is less nutritious than brown rice, even if the total carbohydrate content is equaled out). It’s also important to remember that when we hear about how “bad” sugar is for our health, we’re usually talking about ADDED sugars specifically.
Ok, well what’s the point of carbs then? What do they actually DO?
Carbohydrates are our body’s preferred source of fuel. Carbohydrates are what give all our cells energy, and keep our brain adequately fueled. During exercise our muscles need way more energy than at at rest to fuel our activity, and that fuel comes mostly from carbohydrates! If we aren’t eating enough we can find ourselves hungry, cranky, and with some serious sugar cravings. We might also find our athletic performance seriously impacted (in a bad way!) if we’re underfueling.
So what is it that makes some carbohydrate foods more beneficial for our health than others? Why choose whole grain bread over white bread if the carbohydrates are all broken down the same way? One of the answers to that question is fibre!
Fibre is in fact a carbohydrate, but it acts a bit different from simple sugars and starches when we consume it. We get very few calories from fibre (we lack the enzymes needed to digest it properly), but that does not mean that it doesn’t play an important role in our health. There are different types of fibres in the foods we eat and they play many roles in our digestion. They act as a gel in our digestive tract and slow down how quickly our digested food travels through our intestines, which keeps us from feeling hungry as quickly after eating and helps to keep our bowl movements regular. Fibre from foods is the main source of fuel for many of the bacteria that take up residence in our GI tract as well. These bacteria make up what we call the “gut microbiome”, and research consistently demonstrates that a high-fibre diet has positive impacts on the health and diversity of our microbiome. In using dietary fibre for energy, these bacteria produce a variety of substances which have positive impacts on our health in return, such as reducing insulin sensitivity, reducing risk of colon cancer, and perhaps even improving our mood and mental health. The World Health Organization recently released a very large scale study on fibre and recommends we eat at least 24 grams per day.
So, are there good and bad carbohydrates?
Not so much… sure there are definitely some carbohydrate-containing foods that are better than others, but it’s generally because they offer us other nutrients aside from just carbohydrate calories. Compare for example, two slices of whole wheat bread, and about 10 fuzzy peaches candies. Both have the same amount of carbohydrate, and similar calories, but one is OBVIOUSLY more nutritious than the other….why?
It’s because the whole wheat bread gives us more than just the sugar, more than just the calories. Whole grains have fibre, vitamins, minerals, and more protein too which is going to give our bodies important nutrients, but also keep us feeling full and satisfied for longer. The candy on the other hand contains no additional nutrients, just sugar. It may satisfy a craving for something sweet, but it certainly doesn’t replace all of the nutrients that we get our of a real meal. Even though our bodies metabolize all sugars in the same way, it’s what other benefits a food can provide that make one a better choice vs a not-so-nutritious one.
How much carbohydrate should we be eating in a day?
Well, it all depends. Think of carbohydrates in your diet like gas in your car. The more driving you do, the more gas you use. People with higher activity levels are going to need more calories (and more carbohydrates) than folks who are sedentary. Some people who are trying to manage health conditions such as diabetes find a lower carbohydrate intake is beneficial for maintaining lower blood sugar levels (however in nutrition research a high-fibre diet has been shown to be equally as helpful at managing blood sugar levels). Most of the carbohydrates we eat in a day should be from highly nutritious sources, such as fruit, milk, yogurt, whole grains, and starchy vegetables. We want to limit the “added sugars” we get from things like fruit juice, pop, coffee/sweetened coffee beverages, or candy. For women, we should be limiting our added sugars to no more than 6 tsp (24 grams, or about 100 calories) per day. For men, the limit is 9 tsp (36 grams, or about 150 calories)
But Insulin! Don’t carbs cause diabetes?
A lot of low carbohydrate diet proponents talk about minimizing carbohydrate intake to reduce insulin production, because insulin makes us gain weight, and this weight gain leads to health problems such as type 2 diabetes. They believe that carbohydrate intake of any sort (whole grains, fruit, pop, potatoes, you name it) directly causes us to gain weight more so than any other foods because the insulin needed to get those sugars into our bodies’ cells also trap fat inside our body’s cells which makes us unable to lose body fat. This triggers overeating, further increases in insulin levels, and finally when the body is unable to keep up, type 2 diabetes develops. They believe that if we kept insulin levels in our bodies to a minimum, we’d be home free from weight gain and developing diabetes forever. Some of the most vocal advocates of low carb dieting don’t believe exercise, genetics, or anything else plays a role, it’s all about the insulin and the carbs
Ooookaaay, now this is a classic example of extrapolation of evidence and psuedoscience. I’ll start off by saying that as legit as it sounds when you’re reading that blog or diet book that’s passionately blaming carbs for all of our health problems, it’s not telling you the whole story on purpose. Yes, insulin is a hormone that plays a role in glucose metabolism, by which it allows sugars to enter our bodies cells to either be stored, or used for energy. But insulin itself does NOT CAUSE WEIGHT GAIN AND DIABETES. Our bodies automatically adjust insulin levels to match blood sugar levels and keep them stable. If we’re gaining weight, it isn’t insulin’s fault- it’s that were taking in more calories than our bodies’ truly need, and we’re storing the extra energy as fat. We don’t become insulin resistant because we eat carbs, we become insulin resistant because our body’s fuel stores are full. It’s important to recognize as well that a diet very high in saturated fat has actually been shown to contribute to insulin resistance as well, which is one of the major factors that leads to developing type 2 diabetes, as well as physical inactivity.
Plus, this “carbohydrate-insulin model of obesity” has been studied. A few times actually, and has not been found to be true. Excess calories from any source will cause us to gain weight, there is absolutely nothing special about the impact of carbohydrates on the development of type 2 diabetes.
But, are they really necessary? Do we really NEED to eat carbs?
Honestly… no. I’m not one to tell anyone what they can and can’t do when it comes to what they put in their bodies (unless it’s raw water- don’t drink that shit!), however there’s a few pretty big BUTs that go along with my statement. Just because carbohydrates are not an essential nutrient, that does not mean it makes sense to bypass them altogether. Here’s a few reasons why:
- While our bodies do have the capacity to create new glucose molecules in the liver (you can read more about that process here), it comes at a hefty price. Amino acids from protein are required to complete this process. Some very low-carb high fat diets recommend a relatively low protein content, in which case the body has to turn to the amino acids stored in our body’s muscle mass in order to keep making glucose. That’s bad news for our strength and metabolism!
- While carbohydrates themselves may not be essential, many of the vitamins and minerals that come packaged with them in the food we eat are. If we become too focused on eliminating carbs from our diet we might wind up cheating ourselves out of even more important nutrients. If we try to cut all the carbs out of our diet we’re also going to have a heck of a time eating enough fibre, which is something you don’t want to skimp on.
- Carbohydrates ARE essential to athletic performance, and not just for elite athletes! Time and time again, carbohydrates have been shown to be absolutely key for fueling moderate to vigorous intensity exercise. Trying to follow a low-carb diet while maintaining a high level of physical activity is basically like shooting yourself in the foot and trying to run a marathon. You may FEEL like you’re working really hard when you’re eating low-carb and hitting the gym, but the performance gains just won’t be as fruitful as when you include carbs as part of your pre and post-workout meals.
- There’s just no reason to! Most people LIKE eating foods that have carbs in them, and that should be the only reason we really need to go ahead and enjoy them.
My advice? There’s no need to be afraid because carbohydrates aren’t so bad after all! They keep our bodies fueled and energized, and able to perform in every aspect of our lives. Without them we can feel fatigued, have trouble with memory, cognition, and mood. All you need to do is practice eating the RIGHT amount of carbohydrates for your activity level, and choosing carbohydrates sources that provide you with the best overall nutrition.
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