Carbohydrates – What You Need To Know

Carbohydrates & diabetes

When aiming to improve your diabetes control through diet understanding carbohydrates and the foods which will increase your blood glucose levels is essential. From experience, my patients automatically tend to focus on their sugar intake. Although a good starting point there are some major considerations you should be aware of which I have detailed below.

It’s not just about sugar

This is one I hear often from patients. Following their diagnosis they make an effort to eradicate the sugar from their diet. Out go the cakes, sweets, sugar in drinks, biscuits and fizzy pop and I commend them for it. However, for some patients, their diabetes control doesn’t always drastically improve. This is because the dietary management of diabetes is not just about sugar. Sugar is just one sub category of a much larger group of foods effecting your blood glucose levels known as CARBOHYDRATES.


Carbohydrate is umbrella term for several sub categories of food. Starchy carbohydrates are the first and often the most important category.

Classic examples of starchy carbohydrates foods include:

  • Bread
  • Rice
  • Spaghetti
  • Cereal
  • Oats
  • Pastry
  • Flour
  • Rye
  • Pizza Bases
  • Potatoes – all kinds
  • Crisp Breads
  • Pastry
And the list goes on. Essentially anything made with wheat, flour, rye, oats and potatoes are starchy carbohydrates. Your blood glucose levels are effected by starchy carbohydrates because they are converted into glucose during digestion. It makes sense, starchy carbohydrates are broken down into glucose and therefore raise your blood glucose levels.


The other major subheading under the carbohydrate umbrella is SUGAR. Like starch, sugar is is also broken down into glucose. Therefore, both starchy carbohydrates and sugar are converted to glucose once digested and absorbed. As a result, they both raise your blood glucose levels. There are two distinct categories of sugar. The first refers to added, processed, refined or free sugars. All these words relate to the same meaning. This means the sugars are manufactured by humans. In other words they are added.

Examples of this include:

  • Cakes
  • Biscuits
  • Chocolate
  • Sweets
  • Sugar
  • Honey – usually processed after extraction from the hive
  • syrup – as above
  • cereal bars (can be a combination of starchy and sugar)
  • Jam, marmalade and other spreads
And once again the list continues. Finally, natural sugars found in fruit and dairy products also effect blood glucose levels. Fructose, found in fruit and lactose found in milk and yogurts, but rarely cheese due to processing practices, also needs to be accounted for. We therefore have 1 umbrella term; carbohydrates, of which there are two sub categories – starchy and sugar – and within the sugar subcategory we have 2 further subcategories – processed and natural. This is depicted here in the below diagram. Carbohydrate containing foodYou may have noticed generally all words referring to sugar typically end in ‘OSE’. Glucose, Fructose, Lactose all give an indication that these foods will increase your blood glucose levels. Starchy, sugar and natural sugars will increase your blood glucose.  Generally speaking, each of these subcategories will effect your blood glucose levels at different speeds. However, the most important thing for now is how much total carbohydrate you eat at meals.  This will ultimately decide how well you control your blood glucose levels through diet.

Total Carbohydrates

To reiterate, how much carbohydrate you eat per meal will determine how well you are able to control your blood glucose levels. Those individuals who totally cut out sugar may not see the improvement in their diabetes control they expected unless eating large quantities of sugar originally. You may reduce the amount of processed sugar in your diet but remember you may still be eating too many carbohydrates through starchy carbohydrates fruit, dairy or a combination of all three. Remember, it is the total carbohydrates in your diet.

Type 1 diabetes

In type 1 diabetes it is less about the amount of carbohydrates in your diet. However, not over doing it can help. Type 1 diabetes management is more concerned with matching your rapid acting insulin to the carbohydrates you eat. This process is called carbohydrate counting. We have blogged about this here. 

Type 2 diabetes

People with type 2 diabetes need to reduce the amount of carbohydrates they are eating to lower their glucose levels. This is different from type 1 diabetes. People with type 2 diabetes have difficult converting the glucose in their blood into energy. Therefore, adding too much additional glucose by eating too many carbohydrates can become problematic. We’ve blogged on how much carbohydrate to eat here and have provided more information about type 2 diabetes and diet in our type 2 section.

More information

So far we have covered only some of the story. This article is designed to help you understand where carbohydrates exist in your diet and the effect they have on your glucose levels. Different types of carbohydrates have different effects on your glucose levels. This is called the glycaemic index and the glycaemic load. For more information about this, click here for our article on it. 

Need more help

If you need more support we offer a range of 1:1 consultancy services and online programmes focused on helping you improve your glucose control and health for the long term. These include our type 2 diabetes recovery programme, type 1 glucose stability programme and winning weight loss programme. Go to the pages using the links above or in the headers or get in touch if you have questions.