If you have been recently diagnosed with diabetes you may have a lot of questions. Some of these might be around how to match your insulin doses to your food intake in order to keep your blood glucose in the normal range.
Well-managed nutrition is one of the cornerstones of diabetes care. One of the ways you can do this is called carb counting. This article will explain what carb counting is, how it works, and how you can use it to help manage your diabetes.
What are carbs?
The different nutritional components in your diet can be divided into food groups. The groups are:
- Vegetables: both starchy (potatoes, corn) and non-starchy (carrots, greens)
- Fruits: such as oranges, berries, apples and bananas
- Grains: wheat, rice, oats and food made from them (e.g. bread)
- Protein: meat, fish, eggs
- Dairy: milk, yoghurt and cheese
Carbohydrates are found in some of these foods in varying amounts. There are three main types of carbs:
- Sugars: these can be the natural sugars in fruit and milk, or added sugars such as in sweets
- Starches: including wheat, oats and grains, and starchy vegetables like potatoes and beans
- Fibre: a type of carbohydrate found in plants that isn’t digested and helps maintain gut health
Sugars and starches in your food are both digested and cause your blood glucose to rise. Fibre is not digested and therefore does not have any effect on your blood glucose.
What is carb counting?
Carb counting is an approach to meal planning that focuses on carbohydrates as the main nutrient that affects blood glucose.
Carb counting can help you to manage your blood glucose levels by understanding how different amounts of carbs affect your BG levels and, if you are someone who takes insulin, can help you know how much insulin to take to keep your blood glucose levels within the normal range after eating.
There are many different methods of carb counting, so you may find that another person with diabetes does it slightly differently to you.
How many carbs a day should you eat?
The amount of carbs that should be eaten in a day varies from person to person. There is no ‘one size fits all’ answer.
The amount of carbs you need in your diet depends on a range of factors, including your age, weight, activity level and other factors.
Your healthcare team will help you work out a healthy and balanced diet that fits your lifestyle and needs.
On average, people with diabetes should aim to get about half of their daily calories from carbs. That means that if you eat 1800 calories a day, about 800–900 calories (200–225 grams) of your food should be carbs.
Why do people with diabetes need to count carbs?
Maintaining blood glucose control in diabetes is very important. Elevated blood glucose levels — both after eating and over time — are related to the risk for long-term complications from diabetes.
A study in children and adolescents with type 1 diabetes found that people who use carb counting as a method to adjust their insulin dose have improved long-term blood glucose control.
Carb counting can help you to:
- Stay healthy for longer
- Help you understand how different carbs affect your blood glucose levels
- Feel better and Improve your quality of life
- Allow you to recognise trends with different foods
- Prevent or delay diabetes complications such as kidney disease, eye disease, heart disease, and stroke
Carb counting in type 1 diabetes
Carb counting is an ongoing learning process. As you understand both yourself and your diabetes more, the level of detail that you can use in carb counting will increase.
There are roughly three knowledge levels in carb counting for type 1 diabetes:
- Basic: carb counting basic knowledge is introduced
- Intermediate: the relationship between food, medications, physical activity and blood glucose level is explained and understood
- Advanced: you learn how to match all the above with your food intake, and use your carb-to-insulin ratio to calculate your insulin doses
When using carb counting for your meal, you can calculate the amount of carbs it contains, usually using 15g (gram) portions. The number of 15g portions allows you to work out what dose of your short-acting mealtime insulin to give yourself.
The dose varies from person to person , and your healthcare team will work with you to decide what dose is appropriate for you. The dose often lies between 0.5-1.0 units of short-acting insulin per 15g of carbohydrates.
How to count carbs
Working out the carb content of your food can seem daunting at first, but over time you will find that, especially for your favourite foods, it becomes easier.
The aim of carb counting is to work out the amount of carbohydrate that your meal contains in grams.
If you are eating pre-prepared food, the amount of carbohydrates should be listed on the food ingredients label; check out our article which looks at understanding food labels in more detail. If you are preparing food yourself, then it’s important to understand how to estimate the number of carbs in the ingredients you are using.
There are a number of methods that can help you to calculate carb content, including the plate method, using a food list, and carb counting apps.
In addition, there are education programs, such as DAFNE (which stands for Dose Adjustment For Normal Eating), that can help you with managing your nutrition in diabetes and carb counting.
DAFNE is a comprehensive course for adults (over 17 years old) which aims to help people with type 1 diabetes lead as normal a life as possible, while also maintaining blood glucose levels within healthy targets, to reduce the risk of long-term diabetes complications.
Carb counting for diabetes: a summary
Understanding and managing your nutrition in diabetes is very important. In particular, this includes carb counting — consistency in the amount and source of carbohydrate intake from day to day is associated with improved blood glucose management in people with Type 1 diabetes.
There are a number of ways of counting carbs, including using carb counting apps, the plate method or estimating your carbohydrate intake.
While the amount of carbs you need will be different from someone else with diabetes, carb counting can help you understand how much insulin to administer and allow you to adjust your dose to complement the amount that you are eating. This will help keep your blood glucose in a steady range after a meal.
Your healthcare team will help you understand and recognise the benefits of carb counting which will help you to understand how it can fit into your daily life.
- Chiesa, G., Piscopo, M.A., Rigamonti, A. et al. Insulin therapy and carbohydrate counting. Acta Biomed 2005; 76(S3): 44–48
- Gökşen, D., Atik Altınok, Y., Ozen, S. et al. Effects of carbohydrate counting method on metabolic control in children with type 1 diabetes mellitus. Journal of clinical research in pediatric endocrinology, 2014; 6 (2), 74–78. https://doi.org/10.4274/Jcrpe.1191
- Diabetes Diet, Eating, & Physical Activity. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Accessed 18 March 2022. Available at: https://www.niddk.nih.gov/health-information/diabetes/overview/diet-eating-physical-activity?dkrd=/health-information/diabetes/overview/diet-eating-physical-activity/carbohydrate-counting
- Carb Counting. Centers for Disease Control and Prevention (CDC). Accessed 18 March 2022. Available at: https://www.cdc.gov/diabetes/managing/eat-well/diabetes-and-carbohydrates.html.
- Bergenstal, R.M., Johnson, M., Powers, M.A. et al. Adjust to Target in Type 2 Diabetes: Comparison of a simple algorithm with carbohydrate counting for adjustment of mealtime insulin glulisine. Diabetes Care 2008; 31 (7): 1305–1310. Available at: https://doi.org/10.2337/dc07-2137
- DAFNE, NHS. Accessed 18 March 2022. Available at: https://dafne.nhs.uk/about-dafne/what-is-dafne