Good v Bad carbs

Good v Bad Carbs

We've all heard the references to good and bad carbs, but do we actually know what it means and what the difference is?

2 Types of Carb

Carbohydrates can be split into 2 different categories - complex carbs and simple carbs.

Complex carbs 

  • Complex carbs contain long chains of sugar molecules which the body takes time to break down and use. 
  • They have a low glycemic load, which means that low sugar levels are released at a consistent rate to keep you going throughout the day. 
  • They contain wholegrain which means they are high in fibre, vitamins and minerals which are very important for the body. 

Simple Carbs

  • Simple carbs are made up of easy to digest, basic sugars with little nutritional value - also termed 'empty calories' 
  • They have a high glycemic load, which means that blood sugar levels are dramatically raised on consumption
  • They contain little nutrients - are low in fibre, vitamins and minerals - another reason why they are termed 'empty calories'

Digesting Time 

Clearly we want our food to keep us full and energised over a prolonged period of time. Complex carbs do this, as the body takes time to break them down. Therefore, we feel fuller for longer and have energy for the whole day. Simple carbs on the other hand are broken down very quickly. You get a rush of energy and this is followed by a crash. 

Glycemic Load

The glycemic load, related to glycemic index, estimates how much carbohydrate is in the food and how much each gram of it will raise blood glucose levels. Complex carbs have a low glycemic load which means, per gram of carbohydrate, glucose levels will not be raised too much. Simple carbs on the other hand have a high glycemic load meaning that they raise blood glucose levels a lot per gram of carbs. If you read my post about sugar, you will see the negative effects that spikes in sugar, and therefore insulin have on the body. 


Fibre is very important in our diet. Although we cannot digest it, it helps to slow down the absorption of other nutrients. This prevents spikes and dips in blood sugar levels - which reduces the chance of type 2 diabetes. It helps to lower blood cholesterol which prevents heart disease and also contributes to satiety- feeling full. 


Fruit and Veg

Fruit and veg are simple carbs - they contain basic sugars with short chains. However, in the body, they are treated more like complex carbs as the high fibre content changes the way they are processed. Instead of being broken down quickly, the fibre slows down their digestion and allows energy to be released slowly. This makes fruit and veg an excellent choice of carb. 


Although considered a complex carb, potatoes have a high glycemic load, which means their effect on the body is more like that of a simple carbs. Sugar is released very quickly, causing spikes in blood glucose and subsequently insulin. Potatoes are therefore not a great choice of carb. 

Good v Bad Carb List

Good carbs 

Brown rice
Whole- grain bread
Sweet potatoes
Root vegetables

Bad carbs 

Tables sugar
Corn syrup
Fruit Juice
White bread
Cakes and biscuits
White pasta
Fizzy drinks
Most packaged cereals

Carbohydrates are the main supply of energy for the body and so are important to consume in the diet. However, where we get our carbs from is important, as they are not created equally. Complex carbs are good for us, due to their nutritious content and slow release energy. Simple carbs on the other hand lead to spikes in blood glucose levels, as they cause energy to be released all in one go and therefore should be limited.