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Learn about carb counting

If you’re living with Type 1 diabetes, carbohydrate counting, or carb counting, is an effective way of managing your blood sugar levels. It means that your insulin dose can be individually matched to the amount of carbohydrate you eat and drink.

Being aware of the amount of carbs in food and drinks is important for everyone with diabetes, but carb counting is really helpful if you use basal and bolus insulin.

Although carb counting does take up a lot of time and effort, once you've got the hang of it, it can lead to better blood sugar control and more flexibility when you eat. It doesn't mean total freedom but does mean that special occasions and treats can be more easily looked after so you can adjust your insulin to match.

How to count carbs

Carbohydrates can be counted in two ways, in grams or as carbohydrate portions (CP). One CP is usually equal to 10g of carbohydrate. So find the method that you can understand and that works better for you. 

Once you’ve got to grips with estimating the amount of carbohydrate you are going to eat and drink, you'll need to know your insulin-to-carbohydrate ratio. 

Insulin-to-carbohydrate ratios are different from person to person, so you will have your own personal ratio depending on your age, weight, activity levels and how sensitive you are to insulin.

Your diabetes healthcare team will help you work this out and, eventually, you might even have a different insulin-to-carb ratio for each meal. They will usually estimate your starting insulin-to-carb ratio and then fine-tune this based on your blood sugar control.

If you know how many grams of carbohydrate are in a meal and your insulin-to-carb ratio then you can work out the number of units of bolus insulin you need to take for the meal. So if your meal had 70g of carbohydrate and your insulin to carbohydrate ratio was 1 unit of bolus insulin for every 10g carbohydrate, then you'd need to take 7 units of bolus insulin.

The amount you actually take will also depend on other factors such as your blood sugar level, illness or planned activity.

There are five ways you can count carbohydrate in food and drink.

1. Food labels: using the carbohydrate per portion value

If you look at the labelling on the back of a ready-meal, you'll usually see something that looks like this:

Typical Values 100g contains Each oven baked meal (317g) contains
Energy 433kJ (103kcal) 1372kJ (325kcal)
Fat 1.7g 5.4g
Saturates 0.9g 2.9g
Carbohydrate 14.1g 44.7g
Of which sugars 2.0g 6.3g
Fibre 1.2g 3.8g
Protein 7.1g 22.5g
Salt 0.4g 1.3g

If you ate all of the ready meal, the amount of carbohydrate you would count is 44.7g. It is important to count the total amount of carbs and not the 'of which sugars' value. When using a per portion value, make sure that this is the actual portion you are planning to eat.

2. Food labels: using the carbohydrate per 100g value

On the back of foods like pasta or rice, you'll see food labelling information like this:

Typical Values As sold 100g contains
Energy 1515kJ (360kcal)
Fat 1.0g
Saturates 0.2g
Carbohydrate 77.4g
Of which sugars 0.2g
Fibre 1.8g
Protein 8.5g
Salt <0.01g

When using the per 100g value, calculate the carbs for the actual amount of the food or drink that you are going to have.

This means if you were planning to cook and eat 80g of rice the amount of carbohydrate you would count is 61.9g not 77.4g. It's important to invest in a good set of scales that are flat based, digital and can be zeroed. It is also important that your scales are accurate to within 5g.

The cooked weight of foods like pasta, rice and potatoes will vary from the raw or pre-cooked weight, so check which values you are using.

3. Reference lists and visual guides

If the food your eating doesn't carry nutritional informaton, or you're eating out and they don't have the values, carb counting can be more difficult. 

Reference lists and visual guides, such as Carbs & Cals, will help you estimate carbohydrate. They list the amount of carbohydrate in handy measures, such as one bread roll, one medium banana or one scoop of ice cream. Some reference lists also contain pictures too so you can compare.

4. Recipe nutrition information

Using the Diabetes UK recipe pages can take the hard work out of calculating the carbohydrate content.

But there's no need to throw out your favourite recipes and cookbooks. Taking the time to work out the carbohydrate values of your day-to-day meals helps you build up a personal reference list that you can use again and again.

5. Restaurant and cafe nutrition information

Many restaurants and cafes will now list nutritional information for their products online. You may find information that looks like this:

  Per 100 g Per 114 g serving
Energy 1381.6 kJ 575 kJ
Energy 328.1 kcal 374 kcal
Fat 19.2 g 21.9 g
of which saturates
6.8 g

7.8 g
Carbohydrate 22.2 g 25.3 g
of which sugars
1.4 g

1.6 g
Fibre 1.3 g 1.5 g
Protein 15.8 g 18 g
Salt 3.07 g 3.5 g

Many restaurants and snack bars are now providing nutrition information for their menus in a response to us all becoming more health aware.

The nutrition information for this bacon breakfast roll was online and really easy to find. Bear in mind that the values are average values and the dish that you are served may vary in size and content. You still need to use your judgement and experience in resturants and cafes. 

Three ways to start carbohydrate counting today

The first step to start carb counting is by finding out more information like

  • Do you know which of your food and drink contain carbohydrates? Stop, think and make a mental note of which food and drink will need to be counted.
  • Get label savvy – scrutinise the nutrition labels. Pull the food and drink out of your kitchen cupboards and find out just how much information you have to hand.
  • Practise estimating the carbohydrate content of your meals – use reference lists to check your accuracy.

Interested and want to know more?

To carbo count successfully you will need a lot more information. You will need to learn all about carbohydrates, learn how to adjust your insulin and be dedicated to monitoring your blood sugar levels frequently.

You will also need the support of professionals either in the form of your diabetes healthcare team or one of the structured diabetes education courses available. You can find out about courses available in your area from your diabetes healthcare team.

Find out about DAFNE (Dose Adjustment for Normal Eating)

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