The Science Behind Carbs: Myths & Facts

Carbohydrates, or “carbs” as they’re commonly known, have been at the center of nutritional debates for decades and decades. From low-carb diets to carb-loading, it seems like pretty much everyone and their grandmother has an opinion on how many carbs we should eat and what kind of carbs we should avoid. But what’s the objective truth behind this essential macronutrient? Let’s dive into the science behind carbs, debunk some common myths, and uncover the facts without any of the sensationalization. 

Essentially, all carbohydrates are our molecules made up of carbon, hydrogen, and oxygen. They’re one of the three primary macronutrients our bodies need along with proteins and fats, and serve as our primary source of energy. There are three main types of carbohydrates:

1. Sugars (simple carbs)
2. Starches (complex carbs)
3. Fiber

All of these play different roles in our bodies, and understanding them is the key to making informed dietary choices for optimal health. 

Carbs play a number of crucial roles in how our body functions. 

1. Energy Source: Most of the carbs we eat are long-chain carbohydrates, which our body eventually breaks down all the way into glucose, which is what our cells use for energy. 
2. Brain Function: Our brains prefer glucose as their primary source of energy. 
3. Muscle Function: Carbs get stored in our muscles as glycogen, which gets used when our muscles require quick bursts of energy during exercise. And this glycogen is replenished when we eat carbohydrates after exercise. 
4. Protein-Sparing: Adequate carbohydrate intake allows protein to be used most efficiently for building and repairing tissues, rather than being converted into energy. 
5. Digestive Health: Fiber aids in digestion and promotes gut health and overall satiety. We are still learning more about the benefits of fiber each and every day, but we already know that its great for health.

Not all carbs are created equal.

You may have heard of the infamous glycemic index. But what is it exactly? It’s basically a scale that quantifies how quickly carbohydrate-containing foods can raise our blood sugar once we’ve consumed them. The scale goes from 0 to 100, with pure glucose (sugar / simple carb) having a value of 100.

Generally speaking, foods with lower GIs are considered healthier than those with higher GIs, primarily because they result in smaller blood sugar spikes and therefore smaller insulin spikes, whereas foods which have higher GIs have the opposite impact. Low GI foods can also help with both appetite control and reduce the risk of Type 2 diabetes and heart disease. 

It’s important to note that, like all metrics out there, the glycemic index is not perfect. It does not account for typical portion sizes. Watermelon, for example, has a high GI. Watermelon is also rich in nutrients and has relatively few calories per gram, which the GI does not account for. 

Reality: There is no single macronutrient that is responsible for weight gain or weight loss. Weight gain can only occur when one consumes more calories than one burns. It doesn’t matter whether they’re coming from carbs, proteins, or fats. Gram for gram, carbs actually contain fewer calories than fat. There’s a lot of healthy, nutrient-dense foods, like fruits and vegetables and whole grains, which are moderately high in carbs, but have a whole host of other nutritional benefits as well. 

Reality: While we should limit added sugars in our diet, naturally occurring sugars in fruits, vegetables, and dairy products come with so many other nutritional benefits in the form of fiber and micronutrients and antioxidants. The problem with added sugars is that most food items that contain them, don’t have much nutritional value. This is why the American Heart Association recommends that no more than 6% of our daily calories come from added sugars.

Reality: While low-carb diets can be effective for some people, there is no single diet that’s inherently the best for weight loss. What matters most is our overall calorie balance and the adherence to the diet that works for us as individuals.

Reality. While it may be true that there is no strict dietary requirement for carbohydrates, unlike those we have for essential amino acids from proteins and essential fatty acids from fats, carbs do indeed play a very important role in our bodies. Fiber is absolutely crucial for digestive health, appetite regulation and overall satiety, and has a number of other health benefits that are still be researched. 

Not all carbs are created equal, and here are some of the best sources of carbs to include in your diet. 

1. Whole grains. Brown rice, quinoa, oats, and whole wheat bread are all rich in fiber and provide sustained energy. 
2. Fruits. Fruits offer carbs in nutrient-dense packages with a number of vitamins, minerals, antioxidants, and other healthy compounds. 
3. Vegetables. Non-starchy vegetables in particular are very low in calories but extremely nutrient-dense and fiber-rich.
4. Legumes. There are a number of different kinds of beans, lentils, and peas, each of which offers an potent combination of complex carbs, fiber, and plant-based proteins. 
5. Sweet potatoes. Sweet potatoes are an excellent and nutritious source of complex carbs as well as a number of micronutrients. 

These foods not only provide energy but are nutritionally-dense, and exactly the types of food you want to be consuming.

No food should be completely off-limits in any balanced diet, as this leads to forming unhealthy relationships with food, but there are definitely some carbs which should be consumed in moderation.

• Heavily processed foods: White bread, white rice, other refined grains, many chips, crackers and other snack foods have been stripped of much of their fiber and nutrients and are high in refined carbs and unhealthy fats.
• Sugary drinks: Sodas, energy drinks, and even many fruit juices can be very high in added sugars and low in nutritional value. When it comes to fruit juice, stick to juice with the pulp rather than without, and better yet, make it yourself by blending the whole fruit or consume the fruit whole.
• Candy and sweets: These are essentially purely refined sugar.
• Baked goods: Cakes, cookies, and pastries are often high in added sugars and unhealthy fats. Nothing wrong with these occasionally, but portion control is key.

All of these foods tend to be much higher on the glycemic index and can lead to rapid spikes in blood sugar, followed by crashes. Enjoy these in moderation.

The ideal carb intake varies from person to person based on factors like age, gender, activity level, and overall health. The Dietary Guidelines for Americans 2020-2025 recommend that carbs make up 45-65% of total daily calories.

For an individual consuming 2,000 calories a day, that’s 225-325 grams of carbs. However, there can be significant individual variation and many people may feel better on lower-carb diets, while athletes and very active people might need more carbs to fuel their activities.

Just as important as the quantity of carbs is the quality. Focusing on whole, unprocessed carb sources is generally the best strategy.

1. Don’t Fear Starchy Vegetables: Potatoes, sweet potatoes, and squash can be part of a healthy diet when prepared in a healthy way (think baked, not fried).
2. Watch Portion Sizes: Even healthy carbs can contribute to weight gain if eaten in excess, but this goes for all others macros too, not just carbs.
3. Pair Carbs with Protein and Fat: Ideally consume your fiber- and protein-rich foods first, then your fats and eat your carbs last, whenever possible. Note that you don’t need to do this, but if you want to really control your blood sugar, doing this can result in 50% less severe blood sugar spike as opposed to eating exactly the same food, but having the carbs first. The other benefit is this can help slow digestion and provide more stable energy levels for a longer duration.
4. Consider Your Activity Level: If you’re very active or an athlete, you may need more carbs to fuel your activities. If you prefer to keep a low-carb diet, time your carb intake such that it coincides with the beginning and end of your training sessions, as your body is primed to use them best at those times, both for energy, and recovery purposes.

Related: 7 Healthy Snacking Ideas For A Better You

It’s always a good idea to have an idea of the nutritional profile of the foods that you consume. Always remember that you can go here and here to get more information about this.

Low-Carb and Ketogenic Diets: These diets severely restrict carb intake, most often to less than 50 grams per day for keto diets. While they can be effective for some people, particularly for those who find a normal carb intake to be uncomfortable, they can be difficult to sustain for others. Unless you have a specific reason (e.g. insulin resistance, seizures, digestive discomfort) for restricting your carb intake, it’s best to keep your carb intake within normal levels. For weight loss purposes, it’s best to limiting total calories rather than fixating on carbs.

Gluten-Free Diets: For people with celiac disease or gluten sensitivity, avoiding gluten (a protein found in wheat, barley, and rye) is necessary. However, many gluten-free products are highly processed and not necessarily healthier for people without these conditions. There is no concrete evidence that supports the claim that gluten-free diets are healthier than others.

Blood Sugar Management: People with diabetes need to be particularly mindful of their carb intake, as all carbs can affect blood sugar levels. Counting carbs, choosing low GI options, consuming fat, fiber and protein prior to consuming carbs can help manage blood sugar spikes. Going for a walk an hour after a meal can also significantly help with this.

For athletes and highly active individuals, carbs play a crucial role in performance and recovery. Carb loading before endurance events can help maximize glycogen stores in muscles, consuming carbs during prolonged exercise can help maintain energy levels and carb consumption along with protein after exercise can help replenish glycogen stores as well as help rebuild muscle tissue.

As nutrition science evolves, our understanding of carbohydrates continues to grow. Some areas of current research include:

• The role of the gut microbiome in carbohydrate metabolism
• The potential health benefits of resistant starch
• Personalized nutrition approaches based on individual responses to different types of carbs

While we still have much to learn, the current body of evidence supports the importance of carbohydrates as part of a balanced diet.

Carbohydrates aren’t inherently good or bad – they’re an essential part of our diet that, like all nutrients, should be consumed in moderation. The key is choosing high-quality, nutrient-dense sources of carbs and being mindful of portion sizes.

There’s no one-size-fits-all approach to nutrition. What works best for you may depend on your individual health, fitness goals, and lifestyle. 

Ultimately, a healthy diet is one that you can maintain long-term, meets your nutritional needs, and makes you feel good. For most people, this will include a balanced intake of all macronutrients, including carbohydrates. Overall health comes not just with a good diet, but with physical activity too, even if it’s just consistent walking. 

So the next time you hear someone demonizing carbs, remember that it’s not about cutting out an entire macronutrient group. It’s about making informed choices, focusing on quality, and finding the balance that works best for you. After all, health is a combination of everything – what you eat, how much you sleep, how much you exercise and more. The more of these variables you consistently get right, the better. That said, here’s to learning the science behind carbs, making peace with carbs and embracing a balanced, sustainable approach to nutrition!