Do carbs make us fat? The understanding nutrients series

This blog post means we have reached the end of the understanding nutrients series! 

I thought we should go out with a bang and end with the infamous macronutrient, carbs.

The understanding nutrients series was started to give you an idea of the nutrients in our food and why we need them. You can see all the other nutrients here.

a bread basket with a selection of breads

What are carbohydrates?

Carbohydrates are one of the 3 macronutrients, with the other two being fat and protein. A macronutrient simply means a nutrient we need in large amounts.

Carbohydrates are a broad group that include sugars and starches. They’re made up of singular sugar units that are joined together. Sugars are smaller molecules while starches are big molecules with lots of repeated units.

This post is going to focus mainly on starchy carbohydrates as I've got lots of other posts on sugars. 

Roles of carbohydrates:

Believe it or not, the role of carbohydrates is not to make us fat, as the media often wants us to think. Carbs play many important roles in the body.

Energy: the biggest role they have is that carbohydrates are our main source of energy. This energy is what keeps our body functioning. The carbohydrates we eat gets broken down and digested into glucose. Glucose then goes through a complex series of reactions to provide energy to all of our cells.

human brain

The brain loves glucose, and it uses up the most glucose out of all our organs. Some cells in the body can only run off of glucose, such as red blood cells.

Energy storage: our body runs off of glucose and when we have enough supply, we’re able to store extra carbohydrates for later use. Our body stores carbohydrates in the liver and in muscle.

You may have heard that excess carbohydrates are stored as fat, but this is only when you’re in a calorie excess. But remember that excess calories from any source will be stored as fat. This is because someone is consuming more than their body needs. 

And most carbs that people say are 'fattening' are often not just purely carbohydrates. Like pizza or cake for example. These do contain carbohydrates but they also contain lots of fat and so are high in calories.

cheese pizza

Gut health: carbohydrates also play a role in feeding the friendly bacteria we have in our gut. Certain carbohydrates are not digested by our bodies, so they pass through into the intestines and get used by the bacteria there.

These bacteria then go on to produce things like short chain fatty acids – which can reduce inflammation, they can help us to digest other nutrients, and they support our immune system.

a animated model of bacteria

I don’t get why carbs are so demonised, all I can see are the positives!

How much carbohydrates do we need?

The recommended amount of carbohydrates is 260g a day. We also should have no more than 30g of added sugar a day. Free sugars are those added to foods so found in things like sweets, biscuits, and jarred sauces.

For reference 30g of rice Krispies has 26g of carbohydrates. And 2 custard cream biscuits have 7g of free sugars.

Foods that contain carbohydrates:

Sources of carbohydrates include bread, potatoes, rice, cereals, pasta, dairy, fruit, vegetables, and beans. This won't be an exhaustive list as there’s too many to count!

linguine pasta with sausage and spinach

  • 2 slices of medium white bread - 35.8g of carbs
  • 170g of cooked pasta - 60g of carbs
  • 125g of cooked basmati rice – 34.4g of carbs
  • 100g of baked potatoes – 18g of carbs
  • 120g of cooked green lentils – 16g of carbs
  • 50g of oats – 30g of carbs
  • 100g of kidney beans has 15.1g of carbs
  • 80g of broccoli has 2.8g of carbs
  • 80g of oranges – 6.5g of carbs

What happens if we don’t get enough carbohydrates?

You can't really be deficient in carbohydrates per say, as the body is able to make glucose from other substances, like amino acids (what protein is made out of).

But not eating enough carbohydrates could lead to a condition called hypoglycaemia. This is where your blood sugar levels get too low. This leaves you feeling tired, lightheaded, and weak. Hypoglycaemia is a temporary condition that’s treated by eating some carbohydrates. People living with diabetes have to be more aware of their blood sugars getting too low.

A consistently low carbohydrate intake, for example if you’re following a ketogenic diet, could lead to constipation, weight loss, and irritability.

bowl of cheerios

Key points:

  • Carbohydrates are one of the 3 macronutrients, which we need in large amounts.
  • Carbohydrates are the preferred fuel source for our bodies. They also have a role in supporting our friendly gut bacteria and act as an energy store. 
  • There is nothing inherently fattening about carbohydrates.
  • The average person needs around 260g of carbohydrates a day.
  • Bread, potato, rice, pasta, dairy, fruit, and vegetables are all sources of carbohydrates.
  • You can't really be deficient in carbohydrates, but if your blood sugar level gets too low it can make you feel tired, weak, and light headed.

I hope you enjoyed this finale to the understanding nutrients series!

Bye for now 👋



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