Are Carbs Bad for You? What the Science Actually Says

One minute carbs are your best friend, the next they are the enemy.

From keto to paleo, low-carb diets have taken centre stage in health conversations over the past decade. At the same time, carbs have been blamed for everything from weight gain to sluggishness, leaving many people confused, conflicted, and frankly, a little carb-phobic.

There’s no doubt that food carries emotional weight, and carbs in particular seem to stir up guilt and anxiety. But are carbs really as “bad” as some headlines would have you believe?

Let’s cut through the noise. Are carbs bad for you? Let’s take a look at what the science says, so you can make informed choices without fear or fad-driven confusion.

What Are Carbohydrates, Really?

Carbohydrates, often just called “carbs”, are one of the three main macronutrients, alongside fat and protein. They include sugars, starches, and fibre, and are found in a huge variety of foods from fruit and vegetables to bread, pasta, beans, and sweets.

Your body breaks down most carbs into glucose, which is then used as the primary source of energy. In fact, your brain and muscles prefer glucose to function at their best.

Not all carbs are created equal, though. Simple carbs (like sugar) are digested quickly and can cause rapid spikes in blood sugar. Complex carbs (like oats, lentils, and brown rice) contain fibre and break down more slowly, helping to keep you fuller for longer.

So no, bananas and jelly beans are not the same just because they both contain carbs.

Why Carbs Got a Bad Reputation

Carbs started catching heat in the 1990s and early 2000s, thanks to the rise of low-carb diets like Atkins. More recently, the ketogenic diet has added fuel to the fire, promising rapid fat loss through severe carb restriction.

At the same time, obesity rates were climbing, and carbs, especially refined ones, became an easy target. Headlines blamed bread and pasta for expanding waistlines, and influencers began touting “carb detoxes” and “sugar-free” lifestyles as cure-alls.

But let’s not confuse correlation with causation. Just because more carbs were being eaten doesn’t mean they were the root of the problem. Studies comparing low-carb and balanced diets have consistently shown that it’s calorie intake, not carb content alone, that drives weight changes.

In other words, carbs got caught in the crossfire of sensationalised science and diet culture.

Do Carbs Cause Weight Gain?

Here’s the myth: Carbs make you fat.

Here’s the truth: Eating more calories than your body needs over time leads to weight gain, regardless of whether those calories come from carbs, fat, or protein.

It’s true that eating a high-carb meal can lead to water retention. For every gram of stored carbohydrate (glycogen), your body holds about 3–4 grams of water. That’s why people often drop a few lbs quickly when they cut carbs, it’s mostly water, not fat.

There is also a lot of chatter around insulin. Yes, carbs increase insulin levels. But insulin isn’t a fat-storage hormone that magically makes you gain weight. It simply helps your body use glucose effectively.

So, if you’ve been blaming carbs for weight gain, it might be time to zoom out. The issue isn’t the carbs, it’s the overall energy balance and food quality.

Carbs and Performance: What the Science Says

If you are active, carbs are your best mate.

Carbs are the body’s preferred fuel during exercise, especially higher-intensity efforts like running, weightlifting, or interval training. They help top up glycogen stores in your muscles, which directly supports endurance, recovery, and performance.

Studies have consistently shown that athletes and gym-goers perform better when they consume adequate carbohydrates before and after training. Low-carb diets can work for some people, but for most, they reduce training intensity and slow recovery.

If you have ever felt weak, dizzy, or unusually tired during a workout while eating low-carb, chances are your body was asking for more fuel.

What Are Healthy Sources of Carbohydrates?

Carbs are not just white bread and biscuits. In fact, some of the most nutrient-dense foods on the planet are rich in carbohydrates.

Great sources of complex, fibre-filled carbs include:

• Whole grains like brown rice, oats, and quinoa

• Legumes such as lentils, chickpeas, and beans

• Vegetables including sweet potato, carrots, and squash

• Fruits like apples, bananas, and berries

Compare these to highly refined carbs, white bread, pastries, fizzy drinks, which provide quick energy but little nutrition.

The key isn’t to eliminate carbs but to choose ones that keep you full, energised, and satisfied. Aim for balance, not perfection.

Should You Cut Carbs? Here’s What to Consider

For some people, a lower-carb approach might make sense. Those with certain medical conditions (like type 2 diabetes or PCOS), or individuals who simply feel better eating fewer carbs, can benefit from tailoring their intake.

But carbs themselves are not the villain. What matters most is the quality of your diet as a whole, your lifestyle, and your personal preferences. Rather than fear carbs, get curious about how different foods make you feel. Rigid rules rarely lead to long-term success, but flexibility and self-awareness do.

Final Thoughts: Carbs Aren’t the Enemy

Carbs are not bad for you.

What is bad is the confusion and guilt we have been taught to associate with them. When eaten mindfully, carbohydrates support energy, mood, performance, and overall enjoyment of food.

Let’s stop fearing food groups and start making choices that work for us, not the latest trend.

Want more practical nutrition tips?

Nutrition isn’t one-size-fits-all, and knowing how to fuel your body without stress or restriction can be a game-changer. If you’re ready to ditch diet confusion and build a healthier, more sustainable approach to eating, get in touch for coaching I would love to help.