Carbohydrate counting

Why does carbohydrate counting help?

Carbohydrate is the main type of food, which affects your blood sugar levels. During digestion, carbohydrate foods are broken down into glucose, which is absorbed into the blood stream causing a rise in blood sugar (glucose) level.

Glucose is the body’s main source of fuel and requires insulin to enable it to pass from the blood stream into the body’s tissues.

The amount of carbohydrate you eat determines the amount of rapid acting insulin you need to remove it from the blood stream. Therefore, the more carbohydrate you eat, the more insulin you
will need.

Carbohydrate counting is not about restricting your carbohydrate intake.   It is about learning to give the correct amount of insulin to cover the amount of carbohydrate you have chosen to eat.

What are carbohydrate foods?

Carbohydrate foods are those which contain starch and/or sugar.

Foods containing starch include:

• Bread e.g. white, brown, wholemeal, granary, pitta, naan, ciabatta, chapatti, bagel, tortilla, crumpets etc
• Cereals and breakfast cereals e.g. wheat, rice, corn, oats,

barley, porridge, cornflakes, rice krispies, bran cereals, weetabix, muesli, shreddies, shredded wheat etc

• Pastry e.g. pies, pasties, croissants, danish pastry, sweet pastry, short-crust pastry
• Foods containing flour e.g. breaded/battered coatings, white sauces, Yorkshire pudding, dumplings, pancake
• Cakes and biscuits
• Pasta and noodles
• Rice and cous-cous
• Potatoes and Potato products (potato waffles, croquettes and instant mash)
• Foods containing sugar:
  • Sugar – all types, white, brown, icing sugar, honey, glucose, syrup, treacle, jam, marmalade etc
  • Sweets – hard boiled, jellies etc
  • Drinks sweetened with sugar, glucose drinks, fizzy pop
  • Desserts – ice cream, cakes, puddings, biscuits, jelly.
    Also
  • Fruit, fruit juice, milk and yoghurt (containing natural sugars).

Non-carbohydrate foods

All foods contain a mixture of different types of nutrients, but proteins and fats do not raise blood sugar levels, and these will therefore not be counted.  However, large amounts of these nutrients may delay the absorption of the carbohydrate in your meal – your dietitian will discuss this further with you.

Protein:

• Chicken or turkey without skin
• Lean beef, pork or lamb (including bacon)
• Fresh or frozen fish
• Canned fish e.g. tuna (not in sauce)
• Eggs
• Tofu
• Cheese (hard, soft or cottage)

Fat: 

• Butter
• Margarine
• Cooking oils
• Lard
• Ghee

Carbohydrate counting and insulin adjustment

Carbohydrate counting involves measuring the amount of total carbohydrate (sugar and starch) in your meal or snack and altering your quick acting insulin dose to cover this amount.

You are on a basal bolus regime, which means several daily injections of quick acting insulin and a daily injection of long acting insulin.

Rapid acting analogue insulin

Humalog, Novorapid Fiasp and Apidra – These begin to work immediately after injecting and continue to work for up to four hours.  They have a peak action of 50 – 60 minutes after injecting.  They can be injected immediately before or after a meal. (See page 7 for more details).

Ultra-long acting analogue insulin (background insulin)

Glargine (Lantus) and Detemir (Levemir) – These have an immediate action, but they work for up to 24  hours. They provide a steady release of background insulin and are usually injected once daily. (See page 9 for more details.) This insulin must be taken at the same time every day.

Rounding up and rounding down

Sometimes the total carbohydrate for your meal may not match your insulin to carbohydrate ratio (i.e. 15g carbohydrate).  In order to decide whether to round this up to 20g or down to 10g, you should follow these rules (unless you have a half unit pen):

• If your blood sugar is 4-5mmol/lt pre-meal, you should round down to the nearest whole number.
• If you blood sugar is 6-7mmol/lt pre-meal, you should round up to the nearest whole number.

How to count carbohydrates

Below is an example of a food label. The amount of carbohydrate per half tin of beans is listed. However, you may not want the suggested serving size.  We will therefore look at how to calculate any serving size.

BAKED BEANS – Nutritional information

Typical values	Per 100 g	Amount per half tin serving (207g)
Energy	312 kJ 75 Cal	646 kJ 155 Cal
Protein	4.7 g	9.7 g
Carbohydrate of which are sugars	13.6 g 6.0 g	28.2 g 12.4 g
Fat of which are saturates	0.2 g trace	0.4 g 0.1 g
Fibre	3.7 g	7.7 g
Sodium	0.2 g	0.4 g

414g per tin 

Example: You decide you want to eat the whole tin of beans. Therefore the maths to work out carbohydrate would be:

13.6 ÷ 100 × 414 = 56.3g of carbohydrate in a full tin

(Grams of carbohydrate per 100g of chosen food ÷ 100 × chosen
serving size in grams = grams of carbohydrate in food)

Use the rounding up and rounding down rules to work out
whether you should give five or six units of insulin.

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