Diabetes mellitus (Diabetes) is a chronic medical condition where there too much glucose in the blood due to the absence of insulin or inability to properly use insulin. The recommended range for blood glucose is between 4.0-8.0mmol/L. Blood glucose levels above or below this range are termed hyperglycaemia and hypoglycaemia, respectively. Diabetes management usually consists of a multidisciplinary team including a GP, endocrinologist, diabetes educator and dietitian.
Types of Diabetes
Type 1 Diabetes
In people with Type 1 Diabetes, the pancreas is unable to produce insulin to regulate blood glucose levels. This results in inadequate glucose uptake into the cells for energy and an accumulation of glucose in the blood. Patients with Type 1 Diabetes require daily injections of insulin to manage their blood glucose levels.
Type 2 Diabetes
In Type 2 Diabetes, the pancreas is still able to produce insulin however is unable to effectively use the insulin it produces. In many cases, Type 2 Diabetes can be controlled through diet and exercise alone although some situations require the use of oral medication or insulin injections to manage blood glucose levels.
Gestational Diabetes
Gestational Diabetes is a type of diabetes that occurs during pregnancy in women who otherwise do not have diabetes. It is primarily associated with insulin resistance brought about by hormonal levels blocking the action of insulin. Women with gestational diabetes are at an increased risk of developing Type 2 Diabetes later in life.
Diet
A healthy diet along with an appropriate exercise plan is important for diabetes management. Eating regular meals throughout the day with a focus on even distribution of carbohydrate can help keep blood glucose levels consistent.
The Glycaemic Index (GI) is used to categorise carbohydrate-based foods and is a measure of how quickly the carbohydrate in the food is absorbed by the body. Foods are grouped into low, moderate, or high GI categories. Foods that have a low GI are slowly absorbed, making the release of glucose into the blood stream gradual and sustaining. These foods can prevent rapid rises in blood glucose levels, and have a higher degree of satiety (filling us up for longer) thereby assisting in weight loss. Foods that are quickly absorbed and released into the bloodstream are termed high GI. To maintain optimal blood glucose control, low GI foods are recommended.
Examples of high GI foods include: white bread, scones, rice cakes, jelly beans and soft drinks.
Examples of moderate GI foods include: crumpets, pineapple, sultanas, and basmati rice.
Examples of low GI foods include: apples, pears, sweet potato, sweet corn, rolled oats, pasta, lentils, kidney beans, milk and yoghurt.
For a full database on the GI of most foods, refer to glycemicindex.com
Both the amount and type of carbohydrate eaten will affect blood glucose levels. Although a food may be low GI, if it is eaten in excessive quantities, the total amount of carbohydrate (glycaemic load) ingested for that meal may still cause increased blood glucose levels. Consuming small portions of low GI foods throughout the day is recommended. People prescribed insulin as part of their diabetes management (Type 1 and Type 2) need to ensure that their insulin dose matches their blood glucose level and carbohydrate intake, to maintain optimal blood glucose control. This requires knowledge of how much carbohydrate is in different foods and different portion sizes.
Exercise
Exercise is important for people with diabetes provided their blood glucose and diabetes complications are controlled. To improve glycaemic control, manage body composition and optimise cardiovascular health, patients with diabetes should aim to achieve the following exercise recommendations:
Cardiorespiratory exercise
At least 150 minutes of moderate-intensity cardiorespiratory exercise per week or at least 90 minutes of vigorous intensity per week. These guidelines may be achieved through various combinations of moderate and vigorous intensity exercise.
Resistance exercise
Additionally patients with Type 2 Diabetes are encouraged to do three resistance training sessions each week, exercising all the major muscle groups.
It should be noted that in some instances patients with Type 2 Diabetes may not be able to meet recommended exercise targets. In such situations patients should be encouraged to exercise within any limitations and achieve as much exercise as possible, hopefully progressively increasing their exercise levels to the minimum target outlined above.
For athletes with Type 1 Diabetes, it is recommended to consult with a Diabetes Educator, Sports Physician and Accredited Sports Dietitian to implement an appropriate exercise management plan.
Blood Glucose Monitoring
Hypoglycaemia can result when blood glucose is ≤ 4.0mmol/L; however the onset and symptoms of hypoglycaemia varies between individuals. Self-monitoring blood glucose testing is recognised as an invaluable diabetes management tool, which assists in monitoring the effectiveness of medications, dietary influences and exercise. Blood glucose monitoring is particularly important with regard to exercise to minimise the likelihood of developing hypoglycaemia.
Managing blood glucose levels around exercise
To avoid hypoglycaemia associated with exercise it is recommended that blood glucose readings be taken immediately prior to exercise, intermittently throughout exercise, and upon the completion of exercise. Hypoglycaemia can be delayed and occur up to 24 hours after exercise, therefore blood glucose monitoring is particularly important during the period following exercise. People with Type 1 Diabetes or individuals with Type 2 Diabetes who require insulin should plan ahead with exercise as there is a higher likelihood of exercise-induced hypoglycaemia.
Hypoglycaemia can be avoided by carrying a convenient high GI carbohydrate food that can be consumed at the onset of symptoms or a low blood glucose reading during exercise. Exercise should not be performed when blood glucose levels are > 15.0mmol/L or when ketones are present. It is recommended you see a GP or endocrinologist should this occur.
For more information on this or other sports nutrition topics, subscribe to our newsletter or book to see an Accredited Sports Dietitian for your tailored nutrition management plan.