The Most Misunderstood Nutrient
Over the past two decades, carbohydrates have been blamed for obesity, diabetes, and nearly every chronic disease. Low-carb and keto diets went mainstream. Bread became the villain. But the science tells a more nuanced story: carbohydrates, eaten in the right form and amounts, are essential to health, performance, and even weight management.
What Carbohydrates Actually Do
Fuel your brain — Your brain runs almost exclusively on glucose (derived from carbs). On low-carb diets, cognitive performance and mood often suffer until the body adapts. The brain consumes about 20% of your total energy — it demands a reliable fuel supply.
Power your muscles — During moderate-to-high intensity exercise, carbohydrates are the preferred fuel. Glycogen (stored carbs in your muscles) enables you to train hard. Without it, performance drops and fatigue sets in quickly.
Spare protein — When carb intake is sufficient, your body uses carbs for energy and lets protein do its proper job: building and repairing tissue. In low-carb states, the body breaks down muscle to make glucose through gluconeogenesis.
Support gut health — Fiber is a carbohydrate. It feeds the beneficial bacteria in your gut, supports regular digestion, and reduces the risk of colorectal cancer.
Regulate hormones — Carbohydrate intake supports thyroid function and keeps cortisol in check. Very low-carb diets can raise cortisol and suppress thyroid hormones in some individuals, slowing metabolism over time.
Not All Carbs Are Equal
The quality of your carbohydrate choices matters enormously.
High-quality carbs (prioritize these):
- Whole grains: oats, brown rice, quinoa, whole wheat bread
- Legumes: lentils, chickpeas, black beans
- Fruits: berries, apples, bananas
- Vegetables: sweet potatoes, broccoli, carrots
Lower-quality carbs (limit, don't eliminate):
- White bread, white pasta, white rice (nutritionally stripped)
- Sugary beverages, candy, pastries
- Breakfast cereals high in added sugar
The Glycemic Index — Useful but Overrated
The glycemic index (GI) measures how quickly a food raises blood sugar. High-GI foods cause rapid spikes; low-GI foods cause gradual rises. While it's a useful concept, context matters: a watermelon has a high GI but a low glycemic load (the actual amount of sugar per serving is small). Eating mixed meals (protein + fat + carbs together) also lowers the overall glycemic response.
How Many Carbs Do You Need?
It depends on your activity level:
- Sedentary to lightly active: 3–5g per kg of body weight
- Moderately active: 5–7g per kg
- Highly active or endurance athletes: 6–10g per kg
For a 70kg person doing 4–5 workouts per week, that's roughly 350–490g of carbs daily.
The Bottom Line
Carbs are not the enemy. Refined, ultra-processed carbs eaten in excess are a problem. But whole-food carbohydrates are a cornerstone of a healthy, sustainable diet. Cut them out and you'll likely feel worse, perform worse, and fight harder to maintain muscle.