5 Myths about Carbohydrates You Should Stop Believing

carbohydrates and low carb diets

Carbohydrates are a basic component of the human diet. In fact, they’re one of the three macronutrients, the other two being protein and fat. Your body uses macronutrients for energy. Carbs are abundant in most plant-based foods, including fruits, vegetables, legumes, and whole grains. Your body breaks carbohydrates down into glucose and cells use glucose as a fuel source. Carbohydrates also cause a rise in insulin. This has led some low-carb diet proponents to avoid carbohydrates on the basis that they cause weight gain and contribute to health problems like type 2 diabetes.

Myth #1: Eating More Carbs Will Give You More Energy & Alertness

Carbohydrates are a source of energy for the body, and if you do high-intensity exercise, your body needs carbs to maximize your performance. The form of carbohydrates that muscles use to fuel muscle contractions during exercise is glycogen. When muscles are depleted of glycogen, the ability to work out at a high intensity is diminished.

So, will you feel more alert, energized, and focused if you load up on carbs? Eating a carb-rich diet if you aren’t physically active won’t necessarily perk you up. In fact, a diet of refined carbs and sugar can have the opposite effect. The rapid rise in blood sugar you get when you consume processed carbs can lead to an equally dramatic crash.

In fact, a recent meta-analysis of 31 studies found that consuming carbs reduces alertness within 60 minutes after consuming them. In addition, the study found carb ingestion boosted fatigue 30 minutes afterward. Unfortunately, the study didn’t distinguish between types of carbs, and that matters. We would expect refined carbs to have a negative impact on energy but not healthier carb sources. The best way to keep your energy stable is to eat a balanced diet of fiber-rich carbs, high-quality protein, and healthy fats.

Myth #2: Your Body Handles All Carbs the Same

Extreme low-carb dieters would have you believe your body handles all carbohydrates the same way. That’s simply not the case. Your body handles fiber-rich carb, like legumes, fruits, and non-starchy vegetables, very differently than it does refined grains and starchy carbs, like white rice, pasta, and pastries. Due to the latter’s lack of fiber and high sugar content, these foods trigger a rapid rise in blood sugar and insulin that’s harmful to metabolic health. In contrast, fiber-rich, unprocessed foods, and non-starchy vegetables are slowly digested and won’t cause a sharp rise in post-meal blood sugar.

Some low-carb proponents are quick to demonize all whole grains. However, a study of over 55,000 middle-aged people found women who ate more whole grains enjoyed a 22% lower risk of developing type 2 diabetes and men a 34% reduced risk. The reason? The fiber in whole grains improves insulin sensitivity. Therefore, carbohydrate quality counts. The best carbs are unprocessed and high in fiber. The take-home message? Skip processed carbs and added sugar and stick to mostly whole foods. A helpful rule to follow is to select foods that have at least 1 gram of fiber for every 10 grams of carbohydrates.

Myth #3: Going Low-Carb Is the Best Way to Lose Weight

The best way to lose weight is to upgrade the quality of your diet, in general, and become more physically active. Studies show that you can lose weight on a low-carb diet or a high-carb, low-fat diet. Initially, weight loss is faster on a low-carb diet, primarily due to the loss of water and glycogen stores. However, over the long term, weight loss is roughly equal between the two diets. A 2018 study that followed 600 adults found weight loss was similar regardless of whether the participants followed a low-fat or a low-carb diet.  So, don’t think you have to go low carb to lose weight. More importantly, is the quality of the carbs you consume. Choose wisely!

Myth #4: Eating Lots of Carbs Causes Type 2 Diabetes

The idea that a diet high in carbohydrates causes type 2 diabetes is unproven. Some research shows no association between the number of carbs in a person’s diet and the risk of type 2 diabetes while others show a link between carby diets and type 2 diabetes risk. Some studies even show that diets high in carbs are associated with a lower risk of type 2 diabetes. As you know, carbs that lack fiber cause a rapid rise in blood sugar and this isn’t healthy from a metabolic standpoint. Again, what matters most is the quality of the carbs you eat.

If the composition of the carbs in your diet are fiber-rich, non-starchy vegetables, whole fruit, legumes, and modest quantities of whole grains, you don’t get the swings in blood sugar and the insulin surge that refined carbohydrates and sugary drinks cause. Quantity matters too. Eating too much total food can lead to weight gain, and obesity is a major risk factor for type 2 diabetes.  You don’t need to go on a very low-carb or ketogenic diet to lower your risk of type 2 diabetes. Make the majority of the carbs you put on your plate fiber-rich and unprocessed.

Myth #5: Avoid Fruit Because It Contains Too Many Carbs

People on low-carb diets often avoid or limit fruit in their diet due to their sugar content. Fruit contains natural glucose and fructose, but it is combined with fiber and a variety of phytochemicals that reduce inflammation. We know the fiber in fruit slows the absorption of the sugar and doesn’t cause blood sugar spikes in the way fruit juice that lacks fiber does. Some studies even suggest that phytochemicals in fruit help with blood sugar control. In fact, a prospective longitudinal cohort study in 2013 found that people who consumed more whole fruit, particularly berries and apples, had a lower risk of developing type 2 diabetes. Some fruits are higher in natural sugar than others. If you’re concerned about the natural sugar in fruit, stick to berries as they tend to be the lowest in sugar. Most importantly, eat the whole fruit, not isolated fruit juice.

The Bottom Line

Now, you know why carbs aren’t the enemy. In fact, whole food carb sources are rich in fiber and phytonutrients with health benefits. So, don’t let the extreme low carbers keep you from putting carbohydrates on your plate.



·        Cleveland Clinic Newsroom. “Can Whole Grains Help Prevent Type 2 Diabetes?”

·        Eur J Epidemiol. 2013;28(11):845-858.

·        Research Gate. “Sugar rush or sugar crash? A meta-analysis of carbohydrate effects on mood”

·        British Journal of Nutrition (2014), 111, 342–352.

·        BMJ. 2013; 347: f5001. Published online 2013 Sep 28. doi: 10.1136/bmj.f5001.

·        WebMD. “Low-Fat Diet vs. Low-Carb: And the Winner Is”


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