This article is about whether carbs cause weight gain

Do carbs make you gain weight? Fact or myth

Do carbs make you gain weight?

When you speak to most people about losing weight and what to eat, most people will say they will cut carbs. It’s still commonly thought, it’s carbs that make you gain weight.

But why is this?

There’s plenty of reasons. Like a lot of claims that are factually incorrect, there are small grains of truth.

So, the short answer is no. Carbs do not make you gain weight. But it’s perfectly understandable as to why most people assume that they would.

This article will break down each of those reasons. Then, I will explain why you may want to think again before ditching carbs. Not only for your weight. But for your health, physically and mentally.


If you know me, you know I’m tolerable to most things. But if there’s one thing I can’t stand, it’s nutrition documentaries.

It’s not because of how bad they are, but because there’s usually an undercurrent of bias or a hidden agenda attached to them.

For instance, there’ll be a documentary bigging up Keto or Paleo. This leads to the demonisation of carbs.

This usually starts with someone who’s severely obese and they’re recommended to follow a low carb diet. Low and behold all their health symptoms have dissipated. In these documentaries, they always have more energy and they no longer need to take their medication.

Of course, that’s great and I’ll command anyone who can improve their life. But what I don’t like is how they say, because they cut carbs or meat or sugar or name your food villain.

I’d have more respect if they said; this person has lost a life-changing amount of weight due to cutting their calorie intake.

These documentaries never mention also how they also ate more fruits and vegetables. Or they increased the amount they exercise too.

Cutting out carbs was just one way, they helped them lower their calorie intake.

If they said that, I’d be OK. That’s great. But that doesn’t sell, unfortunately. Sensationalism sells.

If it’s not carbs, which makes us gain weight, what does?

Saying carbs makes you gain weight isn’t telling the whole story. That’s like saying watching Youtube causes bad grades at school. It might be a small factor for some children, but for others, it might help them get better grades.

Overeating on calories is what leads to weight gain. (1)

Carbohydrates are only one component of this equation.

The only way to gain weight is to eat more calories than your body is burning. In theory, you could gain weight from only eating vegetables. That’s only if the calories in all the vegetables you ate, was more than what you burned in a whole day.

To find out how much you burn, have a go on my calculator.

Carbohydrates are one of 4 macronutrients.

The other 3 are fat, protein and alcohol.

All 4 macronutrients have a certain number of calories per gram:

  • Carbohydrates – 4
  • Protein – 4
  • Alcohol – 7
  • Fat – 9

When it comes to calories, fat has the most per gram. More than double carbohydrates.

So when it comes to people gaining weight, it’s not carbohydrates, it’s a combination of all the macronutrients.

Scale weight

A lot of people who claim carbs make you gain weight will have lost a lot of weight from a low-carb diet. This is great if this improves their health.

But this doesn’t mean it was carbs that made them gain weight.

But there is evidence that shows when calories are matched, people who go low carb do lose more weight.

Does this mean calories don’t matter? No, what it means is there’s a difference between body weight and body fat.

You see, when people go on low-carb diets, they will lose a greater amount of body water.

Your muscles and liver carry carbohydrates to use for energy. This is known as Glycogen. On average a person will have around 600g of glycogen in their body.

Every gram of glycogen, in your body, carries 3g of water. When you stop eating carbohydrates, your body will use up this stored glycogen as it has no carbs coming in.

Thus you end up losing this glycogen and water.

So let’s do the maths:

600g of glycogen


6 x 300g water = 1800g

= 2400g of water and glycogen.

From a couple of days, you’d lose 2.4kg. In pounds, this is around 5.28lbs.

When someone starts a low-carb diet and sees a drop of over 5lb in a couple of days, of course, they get excited.

They might be more motivated to lose more weight, as that big drop will be motivating and give someone a greater buy-in.

But when it comes to body fat loss. Many studies and papers show when protein and calories are matched. The rate of body fat loss is pretty much exactly the same. Whether it’s low fat or low carb. (2)


Another claim when it comes to carbs making you gain weight is that they are addictive. Sugar gets the biggest blame for this.

In fact, a former deputy leader of one of our UK political parties has come out and said he suffered from ‘sugar addiction’.

Though I don’t recommend you eat more than the 30g recommended amount of sugar per day. To blame sugar as being addictive and the biggest culprit for people gaining weight is wrong.

Sugar can be part of a healthy balanced diet when eating in moderation. If the amount of sugar you eat is not tipping your calorie balance into a surplus, you’ll be fine. And as long as you’re not eating so much to damage your teeth you’re all good.

But when it comes to addiction, there is little to no evidence to say carbs or sugar is additive.

This great paper looks into people’s intake of sugar and compares it to drug use such as cocaine (3). Let’s put it this way eating sugar is not damaging lives like cocaine does.

Put it this way, nobody is in Tesco snorting a bag of Tate & Lyle.

Processed food

So if carbs and sugar are not addictive, why do I always crave them?

That’s a thing. People think they crave carbs and sugar but they usually don’t. When someone says they are craving carbs, they are not craving boiled potatoes, boiled rice, butterless bread, or apples are they?

No, they crave cakes, cookies, buttered bread, chips, crisps and chocolate. What makes these foods different from the ones above?

That’s it, the foods listed above are pure carbs. The second list of foods is a combination of carbs and fat.

Think about baking cakes as a kid. Eating sugar on its own isn’t exciting. But as soon as you cram that sugar with some creamy butter, then wow when that stuff hits your tastebuds, it does feel like an addiction.

What the body craves is a combination of carbs and fat (4). When you eat foods with the right combination of carbs and fat, this will light up dopamine receptors in your brain, making you want to eat more.

Though we aren’t 100% sure why. I put my money behind the theory during primal times when food was scarce. This was an evolutionary way to get us to eat as much as possible to prepare us for a famine. Unfortunately, evolution hasn’t caught up with the fact we can eat as much of this food as we want and our bodies don’t realise it’s unlikely we will starve.

Don’t take that as fact, I could be wrong on that.

So by cutting carbs out of your diet, you cut out most processed foods by default. The tasty foods you can’t stop eating because of the dopamine receptors in your brains lighting up.

This doesn’t make them addictive, as this isn’t the same effect drugs have on you. It’s more similar to the sensation you get when you see a litter of puppies or stroke a cute cat on the street.


Another reason people lose weight on a low-carb diet is due to a lack of dietary variety.

Evidence does show reducing the variety of what’s eaten can help reduce someone’s calorie intake. (5)

You might notice those silly bodybuilders who claim they eat chicken and broccoli every day to get “shredded”. There is actually a method to their madness. Eating the same boring foods every day will make you want to eat less.

On a low-carb diet, your choices are pretty limited. If you’re vegetarian or vegan then god help you on a low-carb diet.

Most meals will be meat, eggs, fish and some veggies. You’ve also cut all the processed foods, the ones combined with fat (You know the ones, everyone, blame as being the carbs, which make you gain weight).

Once you cut all of that out, your options are quite limited and you’ll probably be less hungry.


The final reason low-carb diets tend to improve weight loss is due to the increase in protein.

When you cut out carbs, you’ll probably eat more protein to compensate.

Protein is what is called the most satiating macronutrient. This means it makes you feel full. This means compared to carbohydrates and fat, you might be more likely to eat fewer calories when eating more protein.

The reason it’s thought that protein keeps you fuller is due to some of the hormones (GLP, PYY etc) it contains. It’s thought it signals to our fullness hormone (Ghrelin), thus our body no longer craves food.

Protein also has the benefit of preserving more muscle mass, meaning you’ll look better and feel stronger.

The beauty is, you can get these benefits without cutting carbs. You just need to find ways to slightly increase your protein intake (6).

Health benefits of carbs

Unlike fat and protein, carbohydrates are not actually necessary for survival. But neither is showering or other things. But life would be far worse without them, same as not eating carbs.

Carbs, especially the wholewheat variations, are rich in fibre. In the UK we don’t eat enough. The average adult gets 18g a day, we need to be getting 30g a day, to reap the most benefits. Fibre has so many health benefits. Benefits include:

  • Lowering the risk of heart disease
  • Managing weight
  • Lowering the risk of diabetes

You can get fibre from a low-carb diet, from vegetables. But eating plenty of beans, legumes and whole wheat bread, will give you the biggest bang for your buck.


Nutrition is a lot more than just calories and weight. We need to eat to get the optimal amount of vitamins and minerals.

Whole-grain carbs and even white carbs, thanks to fortification, are rich in many vitamins and minerals. A lot of people don’t realise when they cut out carbs they are cutting a lot of vitamins and minerals. They may run the risk of developing certain deficiencies.

This is preventable if eating plenty of vegetables on a low-carb diet. But yet again eating wholegrain carbs, beans, is such a great way of getting plenty of vitamins.

Energy source

If you’re looking to get in better shape, fitter or stronger exercise is important. Though diet is the most important factor to lose weight. It’d be wrong not to exercise, it’s vital for your muscles and overall well-being.

Carbs (glucose) are your body’s favourite source of fuel. This is what’s going to get you to perform at the best of your ability.

Yes, your body can make energy from fat or protein, but it’s an inefficient borderline pointless process when you can eat carbs.

It’s not just the best source of energy for your body, it’s also the best for your brain. Here’s a fun little fact; The brain accounts for 2% of your body weight, but uses 20% of the glucose you eat. So yeah it’s pretty damn important you’re eating adequate carbs. (7)

Blue zone countries

Finally, let’s look at the Blue zone. This is a lost of countries with super high life expectancies. (8)

You have countries such as Japan, Italy (Sicily specifically) and Greece.

One thing their diets have in common is that they’re carb-based. Compared to countries like The UK and US, their rates of obesity are far lower.

Though they eat a lot of carbs, what they also eat is a lot of fruits, vegetables, fish, healthy fats and fibre. Rather than being exclusive, their diets tend to be very inclusive.

Maybe we need to stop looking at trying to cut out everything and trying to eat more of what we are already lacking. Such as more fruit and veg, fibre and oily fish.

Risks of low carb diets

Though you may not think it, there are some risks of low-carb diets. These all are perfectly available, I’m not saying you should never do a low-carb diet.

Lack of energy

First is a lack of energy, I went into more detail above. But carbs are our main source of energy, so if you cut them out, don’t be surprised if you’re not feeling as energetic as usual.


Try doing a special occasion without carbs. Back in the day, when I went through all my dieting phases, I tried this. I remember going to a burger place with friends and ordering a burger without a bun and giving away the chips.

Looking back it was quite embarrassing. If you follow a diet, which makes you do things like that, you may want to think again.

Food is a social glue, though you might have to make the odd sacrifice here and there. If you have to take drastic measures like that, this might lead to psychological issues further down the road.

In fact, a lack of flexibility in your diet has been shown to be a poorer indicator of dieting success. Whereas a flexible diet or a diet which includes bread has been to shown give better results (9,10)


Women are recommended not to eat more than 20g of saturated fat per day. Men 30g.

Saturated fats are fats, which are solid at room temperature. These include:

  • Meat fat
  • Butter
  • Coconut oil
  • Cream
  • Cheese

Within the guidelines of saturated fat, these foods are perfectly fine and should be enjoyed on a balanced diet.

But eating too much can raise the level of cholesterol in your system, as well as blood pressure. High LDL cholesterol can lead to artery blockages which can lead to heart attacks and strokes.

This isn’t said to scare you, but just an indication of what can happen.

The evidence does show, high saturated fat diets do increase this risk. (11)

I mention this because, on low carb diets, such as the ketogenic diet, people tend to eat more red meat, cheese and high saturated fatty foods.

Yes, this increases protein which is great but tends to tip people over the saturated fat guidelines. This is combined with eating less fibre too, which also protects against cholesterol. (12)


So, do carbs make you gain weight? I can confidently say carbs in themselves are not making you gain weight.

It’s most likely highly processed foods, which are a combination of fats, carbs and salt, which is making most people gain weight.

Though these foods are no problem in small amounts, in excess they are driving our calorie intake.

As for carbs, they taste great, they fill you up, they are full of nutrients and are shown to be vital in sustaining optimal health.

The moral of the story is, look at what you could be increasing in your diet and stop cutting perfectly healthy things out.

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