Carb counting

Carb counting is working out how much carbohydrate is in your food and adjusting your insulin dose accordingly

Carb counting is an important part of managing your type 1 diabetes. When you eat carbohydrates (both starches such as potatoes, rice and pasta and sugars such as fruit, milk, honey), it’s broken down into glucose and absorbed into your bloodstream where it can be used for energy. Carbohydrates, or “carbs,” are nutrients (coming in the three types: starches, sugars and fibre) found in the food we eat and drink.

Carbohydrates are the body’s source of energy — when your digestive system breaks them down into glucose. Insulin allows your body’s cells to use up and store the glucose in the blood.  That’s why if the amount of insulin is not matched appropriately to the “carbs”, blood glucose levels can go high or low.

Therefore, people living with type 1 diabetes must balance the amount of carbs they consume with the right dose of insulin. That’s why carb counting is so important. It is often said that to manage type 1 diabetes we have to be doctors, mathematicians, personal trainers, and dietitians, all at the same time. This is definitely true when it comes to counting carbohydrates, but with some basic knowledge and practice, carb counting can become second nature!

There are structured education programmes like DAFNE (Dose Adjustment For Normal Eating) and BERTIE Online which help you learn how to count the carbohydrate content of your meals and decide how much insulin you need. You may also find the Carbs and Cals book of interest. Ask your healthcare team for more information about the courses and about carb counting.

Here’s some handy tips to help, but remember to ask your healthcare team for more information or if you’re unsure.

Read the nutrition labels of foods:

  • Be aware of ‘per 100g’ values or ‘per portion’ equivalents as this may not give you the carbohydrate in the portion that you are going to eat
  • For example, in this image, if you were to eat the whole 600g container of chicken and vegetable broth, the carbohydrate that you will consume is 2x the value given in ‘per 1/2 pot (300g)’ and this is 25.2g
  • If the 600g pot of broth was to be shared between 3 people, then each serving would be 200g of broth per person. Therefore, you can use the “per 100g” column to work out the carbohydrate per portion. I.e.: 4.2 x 2 = 8.4g carbohydrate per 200g serving of broth

Measure your food

Nutrition labels can be pretty easy to follow, but only if you know what the size of your servings are. For more accurate carb counts, use measuring cups when serving sizes are given in volume and use food scales to help count carbs. Carrying around a food scale is by no means practical but weighing common foods at home can help you visualise and guesstimate going forward.

Use technology

New carb calculator apps and websites are making carb counting a lot easier, especially when you are eating out or on-the-go! Find a few that you trust, such as the Carbs and Cals app. Technology can not only help count carbs on a meal-by-meal basis, but also keep a record of your diet throughout the week and even months.

Eating out

Like everyone else, you probably eat out at restaurants, buy takeaways or eat at friends or family’s homes. The good news is that this doesn’t have to change because you have type 1 diabetes, although you will need to think a bit more about the foods that you eat, and estimate the amount of carbohydrate in the food.

For those eating more diverse world foods, carb counting can also be a challenge. Speak to your diabetes team dietitians for help with these. It can be helpful to bring pictures of your foods to discuss at appointments and you may also find other resources helpful (for example – Carbs and Cals World Foods).

Checking your blood glucose before you eat and then several hours after eating will help ‘test’ whether your estimate was right. Use this as a learning experience.

For overall health you should also consider how much fat and salt foods contain, particularly if you eat out regularly. Choosing food that is lower in calories, fat and salt doesn’t have to be hard.

Fat and protein can also affect glucose levels and insulin requirements. For most people, the amount of insulin they use will cover their needs but if you frequently indulge in foods that have high amounts of these, speak to your dietitian about other approaches to cover these.

And remember, insulin requirements are also influenced by other things too – for example exercise, being unwell, etc. You can’t account for everything! A better understanding of these takes time and structured education as well as regularly recording and reviewing your glucose data can really help. Do speak to your diabetes team for more advice.

Here are some tips to help you choose well:

  • You won’t always be able to carb count 100% accurately. Just do the best you can in each situation. If you’re at home you can weigh your food and use the most accurate method using the per 100g values. If you’re eating out you can’t do that so you can use the Carbs and Cals app and visually estimate your portion size
  • If you are going to eat out, it is worth looking online before you go to see if the venue provides nutrition information for their dishes
  • Supermarket websites are useful sources of nutrition information
  • No added sugar does not mean no carbohydrate. Make sure you check the nutrition label
  • Although there are some good choices, most fast food items are high in fat and calories, including food items advertised as healthy choices. Chicken and fish can be good choices, but not if they are deep fried. The vegetarian option is not necessarily the healthiest option. Many fast food company websites will detail nutritional information of these food items
  • If you’re having fast food for one meal, try to ensure that the other meals you eat that day contain healthier foods
  • To get all-round nutrition, and help to stabilise blood glucose levels, include different healthy food groups in each meal. For example, protein (meat/fish/eggs) or dairy + starchy food (cereal rice/pasta/potatoes) + vegetables/fruit
  • When choosing from menus avoid dishes described as sautéed, fried or crispy as they are likely to be high in fat
  • Ask for sauce or salad dressings to be served on the side
  • Sauces like ketchup are high in sugar so don’t forget to include the carbohydrate from these when you estimate the carbohydrate in your meal
  • Include salad or vegetables with every main meal to get extra fibre, vitamins and minerals
  • Avocado and olive or rapeseed oils are healthier fats than butter, ghee or palm oil
  • Remember the occasional splurge won’t hurt you. If your favourite dessert is crème brûlée or chocolate cake, save it as a treat and savour it!
  • When you eat out, your meal may be served late, and the portion sizes are likely to be different to those you have at home. To avoid a hypo, and more accurately estimate the carbohydrate in the meal it’s a good idea to wait until the meal has arrived to have your insulin