For our bodies to function efficiently and to its maximum potential, it is important that humans eat well and move their bodies. Having a T1D diagnosis does not make anyone immune from this. It is even more important to ensure the correct foods are being consumed and that exercise is part of daily life.
A report by leading Type 1 Diabetes experts (T1D) from around the world provided consensus on managing blood glucose levels safely while exercising.
The report, ‘Exercise management in type 1 diabetes: a consensus statement’ was published in the Lancet Diabetes and Endocrinology journal and involved a team of 21 researchers, including JDRF Type 1 Diabetes Clinical Research Network (T1DCRN) researchers Professor Tim Jones, Professor Paul Fournier and Dr Carmel Smart. The team undertook a review of current published studies to understand the activity levels of those living with T1D and how different types of exercise affect blood glucose levels.
The study found that a large number of people living with T1D worldwide do not have a healthy body weight or achieve the minimum recommended exercise of 150 minutes per week. Many people find managing their condition while exercising to be difficult, and they might avoid daily physical activity because of this. Delayed low blood glucose levels after exercise is a common fear, as well as loss of control and lack of knowledge.
Research has shown that children and young people with T1D who exercise regularly have reduced cardiovascular disease risk, reduced HbA1c (a marker of long term glucose control) and improved body composition, blood vessel function and cholesterol levels. Adults with T1D benefit from reduced eye and kidney damage and have better chance of achieving their BMI, HbA1c and blood pressure targets compared to inactive people. Importantly, regular exercise also decreases total daily insulin needs.
Some of the findings and recommendations from the report include:
- For everyone with T1D, glucose monitoring before, during and after exercise is essential.
- A blood glucose level of between 7-10mml/L before beginning exercise is generally recommended, to help to protect against hypoglycaemia.
- Responses of blood glucose levels differ according to the type of exercise. It is important to understand the differences between exercises when planning food.
- Hypoglycaemia develops in most people with T1D – both those who regularly exercise and those who don’t – within 45 minutes of starting cardio exercise. All typically required a carbohydrate snack or insulin reduction, or both, before exercising.
- The risk of hypoglycaemia is also increased 24 hours after exercise, with the greatest risk of night-time hypoglycaemia occurring after afternoon activity.
- Foods with a low glycaemic index before exercise could sustain carbohydrate availability in the body and maintain normal blood glucose levels. Sports beverages containing carbohydrates and electrolytes are useful for athletes with T1D who are exercising for a longer duration, as it provides a hydration and fuel source, while preventing hypos.
Blood glucose responses to exercise in individuals with T1D are highly variable and influenced by the location of insulin delivery, the amount of insulin in circulation, the blood glucose concentration before exercise and the composition of the last meal/snack, as well as the intensity and duration of activity. These guidelines therefore do not have a one-size-fits-all approach and people with T1D should speak to their healthcare professional to get individualised advice on how to safely incorporate exercise into their daily routine.
The diet used in the treatment of diabetes is a healthy, well-balanced diet, planned to give all the necessary foods to meet your nutritional requirements. The healthy food pyramid can be used as a good guide for healthy food choices (see pyramid below).It is important to eat regular meals and snacks throughout the day i.e. 3 main meals (breakfast, lunch and dinner) and 3 snacks (morning-tea, afternoon-tea and supper). Never skip or delay a meal*. All meals and snacks should include carbohydrate containing foods and your intake of carbohydrates should be consistent* from day-to-day. Foods containing carbohydrate include bread, breakfast cereals, potato, rice, pasta, crackers, fruit, milk and yoghurt.
A good understanding of carbohydrates is essential for families of children with diabetes. Regular contact with an Accredited Practicing Dietitian experienced in Diabetes care is highly recommended for children with diabetes. Your Dietitian can help with all aspects of nutrition and food including issues with food patterns and carbohydrate spread, growth and development, appetite, physical activity, or just further education and advice on food and diabetes.
* These points may not be as relevant for children on insulin pump therapy; discuss with your Diabetes team.
Low GI and diabetes
It is important to try and include at least one low-glycaemic index (low GI) food at every meal and every snack. Low GI foods increase the blood sugars more slowly and steadily and are more sustaining than foods with a higher GI. Check out the low GI food checklist. Sugar and foods containing added sugars can be included in moderation in a healthy low-GI based diet without upsetting diabetes control.
Does that mean I should only eat low GI foods?
No. There are some foods that have a high glycaemic index value that provide other important nutrients (vitamins and minerals) and are found in the base of the healthy food pyramid (the “eat most” section). These foods (e.g. watermelon and other tropical fruits) should not be excluded and can be eaten in conjunction with other low glycaemic index foods. Combining low and high GI foods together results in a moderate GI effect.
There are also many foods that have a low glycaemic index but are high in fat or have poor nutritional value and are therefore found in the top section of the healthy food pyramid (the “eat least” section). These foods are not recommended to be eaten on a regular basis. So remember, glycaemic index value alone does not determine the suitability of a food – the guidelines of a healthy diet (as illustrated by the healthy food pyramid) are the most important considerations. Stick to the guidelines of the healthy food pyramid and select low glycaemic index food choices where practical.
If you would like to read more about the GI the following references will be useful:
The GI Factor, 2ndEdition, Brand Miller, Foster-Powell, Colagiuri & Leeds, Hodder & Stoughton, 1998
Pocket Guide to the GI Factor for Healthy Kids, Brand-Miller, Foster-Powell, Gilbertson, Hodder 2001
The main nutrients in our diet that give us energy are: carbohydrate, protein, and fat. Understanding how these nutrients and the foods they are in affect your blood glucose and your insulin needs will give you greater confidence when making food choices.
Carbohydrate is a vital source of energy for your body, especially the brain. When your body digests carbohydrate, it breaks it down into glucose, which is then absorbed into the bloodstream. This causes your blood glucose levels to rise.
Carbohydrate is found in lots of different foods, and these foods also provide us with other important nutrients like fibre, vitamins and minerals.
Which foods contain carbohydrate?
- Breads, cereals and other grain foods like rice and pasta
- Starchy vegetables like potato, legumes, and corn
- Dairy foods like milk and yoghurt
- Sugary foods and drinks
Why are carbohydrates important?
The amount of carbohydrate that you eat in a meal has the biggest impact on your blood glucose level. Learning how to estimate how much carbohydrate there is in your meals is important to help you to decide how much insulin you need. Learn more about carbohydrate counting in the next tab.
Carbohydrates are broken down and absorbed into the bloodstream at different rates. The Glycaemic Index ranks foods according to how they affect blood glucose levels. Read more about the Glycaemic Index in the tab above.
Protein is another source of energy in our diets and is the key nutrient that helps the body with growth and repair. Protein is broken down into amino acids in the gut so that they can be absorbed. Protein does not break down into glucose, so does not directly raise blood glucose levels.
The main protein foods are:
- Meats, chicken, fish, & tofu
- Nuts & seeds
Milk and yoghurt are also protein foods. However because they also contain carbohydrate and will raise your blood glucose levels, we have listed them under the carbohydrate foods.
Fats provide the body with energy, and they breakdown into fatty acids. Fatty acids are an essential part of all cells in the body, they also help you to store energy, and provide insulation. Fats also allow the body to absorb fat soluble vitamins. Like protein, fat does not breakdown into glucose, so does not directly raise blood glucose levels.
Fat is the most energy dense nutrient, so it is important not to eat more than you need. Eating a lot of fat may lead to weight gain, which can make your diabetes more difficult to manage.
The main fats in the diet are:
- Oils, margarine, butter*
- Nuts & seeds
- Fried foods* and pastry*
* Indicates sources of saturated fat. Saturated fats can raise your blood cholesterol levels, so limit your intake of this type of fat.