Health trends have thrown themselves all over the food pyramid for the past few decades.
The first health villain in the west was dietary fat. Starting in the 1950s, when the USDA and American Heart Association began pushing low-fat diets, food companies completely reformulated products to remove fat (which required even more processing and often resulted in a higher sugar content).
Red meat followed shortly after as an extension of the low-fat frenzy. People were told to avoid red meat due to its higher saturated fat content.
But in recent days, if there’s one food group that gets a worse rap than others, it’s carbs.
Here’s why, and what you need to know about them.
Why People Think Carbs Cause Weight Gain
The biggest reason carbs are often blamed for weight gain is their relationship with insulin. When you eat carbohydrates, your body breaks them down into glucose, which raises blood sugar. Insulin then helps shuttle that glucose into cells for energy or storage. Because insulin also signals fat storage, many people assume carbs automatically lead to fat gain.
Another reason is the association between carbs and processed foods. Refined products like soda, candy, pastries, and packaged snacks are loaded with simple sugars and calories but contain very few nutrients. These foods are easy to overeat and can lead to weight gain when consumed regularly.
Low-carb diet trends such as Atkins and keto have also shaped the narrative by suggesting that cutting carbs is the only effective way to lose weight. While these diets can lead to short-term results, studies show that weight loss ultimately comes down to eating fewer calories than your body expends, regardless of whether those calories come from carbs, protein, or fat (1).
Simple vs. Complex Carbohydrates
Not all carbs are equal. The type matters more than the quantity for most people.
Simple carbohydrates: These are quickly digested sugars that cause rapid spikes in blood sugar. You’ll find them in soda, candy, white bread, and most processed foods. Eating too many can lead to crashes and more cravings.
However, simple carbs are helpful when your body needs quickly metabolized energy, such as during a long run or immediately following an intense workout. Having a small sweet snack on hand will help replenish your energy quickly when you need it. However, whole foods like fruit and good quality chocolate are going to do a lot more for you here than processed, sugary snacks.
Complex carbohydrates: These are found in foods like rice, oats, legumes, vegetables, and fruit. They contain fiber and micronutrients, and they digest more slowly, providing sustained energy over a longer period of time.
One rule of thumb for identifying carbs is if it’s sweet, it contains simple carbs. If it’s starchy, it’s higher in complex carbs (2).
What Carbs Are Good For
Carbohydrates are the body’s preferred energy source. They play essential roles that cannot be fully replaced by other macronutrients.
Fuel for muscles: Carbs are stored as glycogen in muscles and the liver, and this storage fuels exercise and daily activity. Without enough glycogen, performance and recovery suffer (3).
Fuel for the brain: Glucose is the primary fuel for brain function, helping with focus, memory, and mood stability.
Digestive support: Many carb-rich foods provide fiber, which feeds healthy gut bacteria and regulates bowel movements (4).
Hormonal regulation: Carbs affect hormones like leptin, ghrelin, and thyroid hormones, which help regulate hunger, satiety, and metabolism.
When Carbs Are Essential
There are times when carbohydrates are not just helpful, but absolutely essential.
Athletes and active individuals: Carbs restore glycogen after exercise and power high-intensity workouts. Without them, both endurance and strength can drop.
Women’s hormone health: Very low-carb diets can disrupt hormone balance and affect menstrual cycles. Balanced carb intake supports energy and reproductive health.
Post-workout recovery: Carbs paired with protein help replenish glycogen and repair muscle, which speeds recovery and improves adaptation to training (5).
Daily function: Carbs fuel focus, mood, and mental performance, helping you show up fully for work, family, and training.
Carbs do not inherently cause weight gain. Overeating calories from any source, whether protein, fat, or carbs, leads to weight gain. What matters most is the quality of the carbs, the overall balance of your meals, and your lifestyle context. Choosing carbs that digest easily, support energy, and provide nutrients, then pairing them with protein and healthy fats, is the best approach for long-term health and sustainable weight management.†
† We are required to say these statements have not been evaluated by the Food and Drug Administration. This content is for informational purposes only and is not intended to diagnose, treat, cure, or prevent any disease.
Sources
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Blaak, E., Riccardi, G., & Cho, L. (2021). Carbohydrates: Separating fact from fiction.. Atherosclerosis. https://doi.org/10.1016/j.atherosclerosis.2021.03.025.
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Ferretti, F., & Mariani, M. (2017). Simple vs. Complex Carbohydrate Dietary Patterns and the Global Overweight and Obesity Pandemic. International Journal of Environmental Research and Public Health, 14. https://doi.org/10.3390/ijerph14101174.
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Craven, J., Desbrow, B., Sabapathy, S., Bellinger, P., McCartney, D., & Irwin, C. (2021). The Effect of Consuming Carbohydrate With and Without Protein on the Rate of Muscle Glycogen Re-synthesis During Short-Term Post-exercise Recovery: a Systematic Review and Meta-analysis. Sports Medicine - Open, 7. https://doi.org/10.1186/s40798-020-00297-0.
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Clemente-Suárez, V., Mielgo-Ayuso, J., Martín-Rodríguez, A., Ramos-Campo, D., Redondo-Flórez, L., & Tornero-Aguilera, J. (2022). The Burden of Carbohydrates in Health and Disease. Nutrients, 14. https://doi.org/10.3390/nu14183809.
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Saris, W., Astrup, A., Prentice, A., Zunft, H., Formiguera, X., De Venne, W., Raben, A., Poppitt, S., Seppelt, B., Johnston, S., Vasilaras, T., & Keogh, G. (2000). Randomized controlled trial of changes in dietary carbohydrate/fat ratio and simple vs complex carbohydrates on body weight and blood lipids: the CARMEN study. International Journal of Obesity, 24, 1310-1318. https://doi.org/10.1038/sj.ijo.0801451.
