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The Importance of Quality Carbohydrates in Human Nutrition

Updated: Oct 16, 2023


A white bowl of assorted fruits surrounded by whole grains and other fruit

Carbs, carbs, carbs – it seems like they've become the villain of the food world, right up there with the broccoli that kids love to hate. Seriously, how many times have you heard someone brag about their "carb-free" day or how they've transformed into a keto superhero overnight? If I had a dime for every time someone praised carb-cutting, I could probably afford that fancy coffee with the extra foam!


But hold on a second – why are carbs getting such a bad rap when they bring so much to the flavor party of life? It's time we set the record straight because not all carbs are created equal, my friends.


You see, science has known for a while that not all carb sources are born identical. So, how did they all get thrown into the same diet dungeon and labeled as evil sugar monsters? Well, I've got a theory. It's like that old game of telephone, where the message gets muddled as it's passed along. Decades ago, low-carb diets burst onto the scene, and somewhere along the way, the line between high-quality carbs and the not-so-great ones got all blurry.


We've seen those TV shows where they claim you need to cut out carbs entirely, exercise like a maniac five days a week, and basically become a carrot to lose 50 pounds. But let me drop some truth bombs – exercise is excellent, but implying that you have to do it like a professional athlete and swear off anything delicious to shed pounds is pure fiction.


Here's the real deal: the number of carbs you eat doesn't magically control the numbers on your bathroom scale. What truly matters is a simple math equation: calories in < calories out. In other words, the energy you get from food needs to be less than what you burn through daily activities to lose weight. Now, don't get me wrong, you can't go wild on carbs and expect no consequences because they do bring in calories. Plus, the quality of the carbs you chow down on can have a big impact on your health. So, in this article, I’m serving up the lowdown on why it's the quality, not just the quantity, of your carb choices that counts – and I promise to keep it carb-mic.


Carbs Unveiled: The Flavorful Journey


Embark with me on a fun journey through the carb world, where we'll explore their differences. Think of it as sorting carbs into different boxes based on their sugar chain lengths. We have the cool monosaccharides (glucose, fructose, galactose) and the duo disaccharides (lactose, sucrose, maltose), aka simple sugars (Ludwig et al., 2018). Then there are the complex carbs that come in various shapes and sizes. Oligosaccharides have 3-10 sugars, and the big shots, polysaccharides, can have over 1000 sugars (Ludwig et al., 2018). It's like organizing a sweet parade of carbs!


Let's meet our carb celebrities: plant starch, resistant starch (RS), and dietary fiber. Plant starch is like the popular kid, created in specialized plastids called amyloplasts in leaves and crops (Lovegrove et al., 2015). Starch and resistant starch are the dynamic glucose duos, packed into tiny crystallized granules (Lovegrove et al., 2015). Then there's dietary fiber, the fiber superhero, found in plant tissues and seeds. It comes in two flavors, soluble and insoluble (Lovegrove et al., 2015). Soluble fiber parties with resistant starch in your large intestine, helping with blood sugar and metabolism (Lovegrove et al., 2015; Reynolds et al., 2019). Insoluble fiber is more of a cleaning crew, sweeping through (Ludwig et al., 2018). These carb stars hang out in whole grains, veggies, fruits, and legumes (Lovegrove et al., 2015).


A picture of two hands holding white rice and brown rice

Now, we'll chat about carb quality, because not all carbs are created equal. It's all about how your body deals with them, their impact on blood sugar, and how they affect your health (Ludwig et al., 2018). It's like figuring out if your carb is the life of the party or the party pooper. Carbs start their digestion adventure in your mouth, with enzymes like salivary amylase (Lovegrove et al., 2015). Then they travel down to your stomach, where they're broken down further for a small intestine adventure (Lovegrove et al., 2015). Any undigested or rebellious carbs end up in the large intestine, where they might ferment or take an express route out (Lovegrove et al., 2015; Reynolds et al., 2019; Hills et al., 2019). This digestion process varies depending on the carb's structure. Raw crystalline polysaccharides don't fully digest, offering fewer calories (Hardy et al., 2015). But when you cook them, they become more digestible and calorie-rich, like magic (Lovegrove et al., 2015). It's not about the length; it's all about the structure (Ludwig et al., 2018).


The pace at which carbohydrates undergo digestion plays a crucial role in their impact on blood sugar levels. When carbs are digested, they transform into glucose, and it's your pancreas that acts as the traffic cop, deciding whether to utilize this glucose for immediate energy or stash it as glycogen (Ludwig et al., 2018). Simple carbs, found in sugary treats and refined grains, get rapidly digested, causing blood sugar roller coasters (hyperglycemia). In response, your body releases a surge of insulin, leaving you feeling hungrier and more fatigued (Ludwig et al., 2018). Consistently consuming carbs that cause these blood sugar spikes can actually dull your body's response over time.


But complex carbs, like starch and dietary fiber, take their time thanks to their gelatinized form when cooked (Ludwig et al., 2018). This slower digestion offers a controlled glucose release and a balanced insulin response, keeping your energy levels steady. So, choose your carbs wisely for a smooth energy ride!


Now that we know a bit about carbs, we need to gauge how they play with our blood sugar; that's where our trusty sidekick, the glycemic load (GL), swoops in to save the day. Forget just eyeballing a food's macronutrient content; GL is the real detective here, giving us the lowdown on how much a serving of carbs might shake up our blood sugar, all thanks to their glycemic index (Ludwig et al., 2018).


Imagine simple carbs as the high rollers, often packing a punch with those higher GLs, while our buddies, the complex carbs like starch and dietary fiber, keep it cool with their lower scores (Lovegrove et al., 2015). So, as you embark on your carb journey, consider the kind of party they'll throw in your bloodstream and how they'll keep your energy levels groovin'! It's not just about quantity; it's about the quality of the carb experience.


Quality Carbs for Health’s Sake


When it comes to carbs, they're not just about filling your belly; they play a big role in how your body does its thing. Picture this: you've got carbs on one side, the good carbs, and on the other side, the not-so-good ones. The good ones, the low GL, high-fiber champs like whole grains, legumes, and fruits (Ludwig et al., 2018; Reynolds et al., 2019; Schwingshackl et al., 2019), they're like the cool kids at school. Hang out with them, and you'll see some serious reductions in body weight, cholesterol levels, and even your risk of heart disease and type 2 diabetes (Ludwig et al., 2018; Reynolds et al., 2019; Schwingshackl et al., 2019).


As for fruit juice; it's not even in the same league as real fruit. It's like trying to enjoy a concert with no music; it lacks the dietary fiber that makes fruit so awesome, and it sneaks in simple sugars (Ludwig et al., 2018). So, stick to the real deal.


What about about the not-so-good carbs, the ones with a higher GL? We're talking about refined grains like white rice and potatoes – they're like the party crashers (Ludwig et al., 2018). Hang out with them too much, and you might gain some unwanted weight and be at a higher risk of becoming best buddies with type 2 diabetes (Ludwig et al., 2018). And those added sugars? They can mess with your energy intake and body weight (Ludwig et al., 2018). So, the World Health Organization (WHO) recommends keeping them in check, less than 10% of your daily energy intake, with extra brownie points for less than 5% (Ludwig et al., 2018).


This is where it gets interesting - carbs aren't just about you; they've got a whole fan club in your gut! The large intestine is like a bustling city, filled with colonocytes and bacteria working hard to keep things in balance (Hills et al., 2019). Your gut microbiome is your personal entourage, influencing your BMI, blood glucose, and even your cholesterol levels (Hills et al., 2019). These colonocytes, the unsung heroes, help you burn energy and control your food cravings (Hills et al., 2019).


And what does this microbiome have to do with carbs? Well, when resistant starch and dietary fiber show up at the party, they get fermented and turn into short-chain fatty acids (SCFAs), like the DJ of the night (Lovegrove et al., 2015; Ludwig et al., 2018; Reynolds et al., 2019; Hills et al., 2019). These SCFAs are the energy source for your colon cells, keeping the party going strong (Hills et al., 2019). And they're not just about the energy; they help break down glucose and fat in your gut (Hills et al., 2019). Plus, they've got a hand in the mental game, making you feel good (Hills et al., 2019).


An illustration of the gut microbiome

Here's the kicker - if you ditch starch and fiber, it's like kicking your entourage out of the party. Your gut bacteria get all out of whack, and that's bad news, leading to frailty, inflammation, and other not-so-fun stuff (Hills et al., 2019). And artificial food ingredients? They're like the party crashers that ruin the vibe (Hills et al., 2019). So, starch and fiber, they're the real MVPs; don't skip them!


Now, for the big drama - carbs and colorectal cancer. Excessive non-fiber, high GL carb intake is the real villain in this story (Maino Vieytes et al., 2019). There's this thing called the Warburg Effect, where simple carbs activate the insulin-IGF-1-axis, giving tumor cells the upper hand (Maino Vieytes et al., 2019). They thrive on insulin resistance, and it's like giving them a superpower (Maino Vieytes et al., 2019). High-fiber polysaccharides, though, they're the protagonist, disrupting this insulin-IGF-1-axis, and showing cancer cells the exit (Maino Vieytes et al., 2019; Reynolds et al., 2019).


Cooking: Carbs’ Evolutionary Twist


Let's rewind a bit and think about our evolution. Carbs have been by our side for a long time. Back when Homo Erectus made their debut, they brought with them some impressive upgrades, like increased height, brain size, and even the ability to run marathons (Hardy et al., 2015). And you know what? Carbs were there too, playing a vital role in our development (Hardy et al., 2015).


Our brains, they're like luxury cars, needing tons of energy to run (Ludwig et al., 2018). So, having more energy from carbs would make sense for our brain growth (Hardy et al., 2015). And here's the fun part – cooking! It's our hidden ace. See, raw starch is a tough nut to crack, giving us minimal energy (Hardy et al., 2015). But once we figured out cooking and turned starch into an energy powerhouse, our genes partied hard, with more copies of amylase genes (Ludwig et al., 2018; Hardy et al., 2015).


The transition from a high-volume, low-energy diet to a high-energy, low-volume one was a surprising turn in our evolutionary story. (Hardy et al., 2015). With our small digestive systems demanding less energy, our brains got more glucose to play with (Ludwig et al., 2018). It's like upgrading from a regular smartphone to the latest model – more power to the brain!


So there you have it, the story of carbs and their epic journey from the beginning of our evolution to their starring roles in our health.


Early hominids sitting around a campfire

Carbs: Boosting Health and Athletic Performance


When it comes to these findings, here's the scoop: while glycemic load (GL) and glycemic index (GI) certainly have their significance, the real star of the show for making your health happy is the fiber content of your food. Reynolds et al. (2019) showed that aiming for around 25-29 grams of fiber a day is the sweet spot for reducing your risk of all sorts of health hiccups. Sure, glycemic index plays a part, but it's like the sidekick – not the hero – in this story, especially when compared to the mighty dietary fiber (Reynolds et al., 2019).


So, what's on the menu for healthy hearts and happy bellies? Well, there's the DASH, paleo, and Mediterranean diets, and they've got the blood pressure-lowering quirk (Schwingshackl et al., 2019). But here's something intriguing – even the low-carb diet gets in on the action, likely because it involves ditching the simple carbs (Schwingshackl et al., 2019). As the data tells it, diets that play it cool with low GL carbs and high fiber are your ticket to a reduced-risk wonderland.


For all you athletes out there, carbs have some cool tricks up their sleeves too. If you're into endurance sports that go on for over an hour, carbs become your best buddies. You're talking about chomping down around 60-80 grams of carbs per hour (Jeukendrup, 2014). They're like your energy boosters, delaying fatigue, keeping you going, and making you a champ, especially if your sport involves start-and-stop action (Jeukendrup, 2014). And if you're sipping on carb drinks during the long haul, they're a magic potion, making you feel less tired and giving you more power (Jeukendrup, 2014).


A group of runners racing on asphalt

When it comes to pumping iron, sadly, carbs aren't the stars of the show, at least not when you're well-fed (Henselmans et al., 2022). Your body's got this fantastic ability to store and use energy during strength training, especially if you're doing around 10 sets or less for each muscle group and taking those chill rest breaks (Henselmans et al., 2022). In those cases, fat becomes the main player in the energy game (Henselmans et al., 2022).


But, for the competitive athletes or those going full throttle in high-intensity workouts, carbs step back into the spotlight. It's like a backstage pass to maximizing your energy reserves. Aim for around 0.3 grams of carbs per kilogram of your body weight within 3 hours before your event or go big with 1.2 grams per kilogram if you've got another workout later that same day (Henselmans et al., 2022). It's akin to giving your body the VIP treatment, ensuring those glycogen stores are in top-notch shape for your big performance (Henselmans et al., 2022).


In Conclusion: Carbs Reimagined


In the grand theater of nutrition, where carbs have been both the heroes and villains, it's crucial to decipher the plot with a discerning eye. Carbohydrates, often maligned as sugar monsters, deserve a fair reevaluation. The key lies not just in quantity but in the quality of carbs we choose to embrace. While low-carb diets may have had their moment in the spotlight, science beckons us to recognize that not all carbs are cut from the same cloth. From the sweet parade of monosaccharides and disaccharides to the dynamic duos of plant starch, resistant starch, and dietary fiber, carbs offer a vast array of flavors for us to explore.


Our digestive system, resembling a well-choreographed dance, responds differently to various carbs, depending on their structures. Cooked crystalline polysaccharides metamorphose into a digestible form, keeping our blood sugar levels in check and ensuring a steady supply of energy. When it comes to health outcomes, fiber content emerges as the true hero, overshadowing the glycemic index. Diets that prioritize low glycemic load carbs and dietary fiber have the potential to lead us to the wonderland of reduced health risks.


For athletes, carbs unveil their energy-boosting powers, particularly in endurance sports. Chomping down on carbs during prolonged exertion delays fatigue and elevates performance. Yet, in the realm of strength training, carbs step aside, letting fat take the spotlight, provided one is well-fed. Competitive athletes, however, reap the benefits of carb-loading before intense workouts, ensuring their glycogen stores are in peak condition for an outstanding performance.


In the end, the story of carbs spans our evolution, from their role in our brain's energy demands to the culinary magic of cooking. It's a tale of adaptation and transformation, with carbs as constant companions in our journey towards improved health and well-being. So, as we bid adieu to the carb roller coaster, let us remember that the quality, not just the quantity, of our carb choices indeed counts, ensuring that our dietary choices align with the harmony of our health and our heritage.


Citations


Fat “Shield” protects immune cells-and some cancers-from destruction. Columbia University Irving Medical Center. (2021, August 9). https://www.cuimc.columbia.edu/news/fat-shield-protects-immune-cells-and-some-cancers-destruction#:~:text=Natural%20killer%20cells%20are%20our,or%20cancer%20cells%20each%20day.


Hardy, K., Brand-Miller, J., Brown, K. D., Thomas, M. G., & Copeland, L. (2015). The importance of dietary carbohydrate in human evolution. The Quarterly Review of Biology, 90(3), 251–268. https://doi.org/10.1086/682587


Henselmans, M., Bjørnsen, T., Hedderman, R., & Vårvik, F. T. (2022). The effect of carbohydrate intake on strength and resistance training performance: A systematic review. Nutrients, 14(4), 856. https://doi.org/10.3390/nu14040856


Hills, R., Pontefract, B., Mishcon, H., Black, C., Sutton, S., & Theberge, C. (2019). Gut microbiome: Profound implications for diet and disease. Nutrients, 11(7), 1613. https://doi.org/10.3390/nu11071613


Jeukendrup, A. (2014). A step towards personalized sports nutrition: Carbohydrate intake during exercise. Sports Medicine, 44(S1), 25–33. https://doi.org/10.1007/s40279-014-0148-z


Lovegrove, A., Edwards, C. H., De Noni, I., Patel, H., El, S. N., Grassby, T., Zielke, C., Ulmius,

M., Nilsson, L., Butterworth, P. J., Ellis, P. R., & Shewry, P. R. (2015). Role of polysaccharides in food, digestion, and health. Critical Reviews in Food Science and Nutrition, 57(2), 237–253. https://doi.org/10.1080/10408398.2014.939263


Ludwig, D. S., Hu, F. B., Tappy, L., & Brand-Miller, J. (2018). Dietary carbohydrates: Role of quality and quantity in chronic disease. BMJ. https://doi.org/10.1136/bmj.k2340


Maino Vieytes, C. A., Taha, H. M., Burton-Obanla, A. A., Douglas, K. G., & Arthur, A. E. (2019). Carbohydrate Nutrition and the risk of cancer. Current Nutrition Reports, 8(3), 230–239. https://doi.org/10.1007/s13668-019-0264-3


Reynolds, A., Mann, J., Cummings, J., Winter, N., Mete, E., & Te Morenga, L. (2019). Carbohydrate quality and human health: A series of systematic reviews and meta-analyses. The Lancet, 393(10170), 434–445. https://doi.org/10.1016/s0140-6736(18)31809-9


Schwingshackl, L., Chaimani, A., Schwedhelm, C., Toledo, E., Pünsch, M., Hoffmann, G., & Boeing, H. (2018). Comparative effects of different dietary approaches on blood pressure in hypertensive and pre-hypertensive patients: A systematic review and network meta-analysis. Critical Reviews in Food Science and Nutrition, 59(16), 2674–2687. https://doi.org/10.1080/10408398.2018.1463967

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