Sports nutrition for Type 1 Diabetes

General guide lines for dietary management for sports persons with Type1 diabetes...

Mrs.Mini Sharama
― Dietician
M.V Hospital for Diabetes, Royapuram

Can people with Type1 diabetes seriously think about taking part in a major event such as the Olympics?

Type 1 diabetes is a condition in which the body is unable to produce insulin. Without insulin, the body's ability to use glucose as a fuel source is impaired. That does not mean that people with Type 1 diabetes have to give up their dreams of a successful sports career. Pakistani batsman and fast bowler Imran Khan and swimmer Gary Hall Jr. are just a few athletes with Type 1 diabetes who have competed at the highest level of demanding sports. With good management, it is possible to participate in sporting activities with this condition.

Why is insulin important?

Insulin is a hormone produced in the pancreas. It has a number of important functions in the body, including a regulatory effect on carbohydrate metabolism.

Insulin stimulates body cells to take up glucose and use it for fuel.

It inhibits the release of glucose from glycogen in the liver and stimulates the synthesis of muscle glycogen after exercise.

In the absence of diabetes, insulin is released according to the body's needs and the concentration of glucose in the blood is kept within a tight range.

People with Type 1 diabetes do not produce insulin and so the body is unable to use glucose properly as a fuel source and starts to rely on fat and protein as fuel. This causes blood glucose levels to rise excessively and toxic by-products from fat breakdown (ketones) to build up in the blood. . Therefore, regular insulin injections are needed to simulate what the pancreas would be doing if it could make insulin.

The amount and timing of insulin administration needs to be matched to factors such as food intake, individual metabolism and activity level.

How does exercise affect diabetes management?

Factors such as muscle contraction, increased blood flow and increased body temperature cause the body to be more responsive or 'sensitive' to insulin during and soon after exercise. When muscles contract, they can also independently absorb glucose from the bloodstream.

Therefore, in people who do not have diabetes, insulin release decreases during exercise. People with Type 1 diabetes usually need to adjust their insulin dose to account for a reduced requirement for insulin during exercise.

Management of diabetes varies for each individual. Regular monitoring of blood glucose concentrations and trial and error (under the supervision of your diabetes specialist) is needed to understand and manage each individual's response to exercise.

How does Type 1 diabetes affect sport nutrition strategies?






General sports nutrition strategies are similar whether or not you have diabetes. Managing Type 1 diabetes and competing successfully requires a commitment to trials of different food and fluid combinations in and around exercise. It is impossible to provide a single set of guidelines that will suit all people with Type 1 diabetes. Here are some guidelines to consider. You will need to work with your diabetes specialist and dietitian and use trial and error to find the best approach for you.

Effect of diabetes on dietary needs...

Blood glucose control in athletes with Type 1 diabetes is usually better when exercise patterns and eating patterns, including meals and snacks, are consistent. In general, athletes with diabetes have the same dietary requirements as athletes without the condition- plenty of vegetables, fruit, beans, breads, and cereals; moderate amounts of fish, meat, poultry, eggs, and dairy products; and smaller amounts of refined sugar, alcohol, and foods high in fat.

Needs for energy, carbohydrates, protein, and fat are as follows:

* Athletes with Type 1 diabetes need to consume enough food for energy in order to stay healthy, maintain a desirable body weight, and train and compete effectively. This includes making adjustments when the intensity and/or duration of exercise changes.


*Carbohydrates are needed on a daily basis to maintain blood glucose levels and to replace glycogen stores. The recommended range for athletes is typically 2.7–4.5 grams/lb (6–10 grams/kg).

* Protein intake recommendation for both endurance and strength athletes with diabetes is 0.5–0.8 grams/lb (1.2–1.7 grams/kg).

* After carbohydrate and protein needs are met, healthy sources of fat can provide the remaining caloric needs. Healthier sources of fat include monounsaturated and polyunsaturated fats from plants, such as vegetable oils, nuts, seeds, and avocados.


Carbohydrate-containing foods with a low glycemic index can assist with blood glucose control. Glycemic index is a tool used to rank foods according to their immediate effect on blood glucose levels. Carb-containing foods that are broken down quickly are also called high glycemic index foods and will rapidly release glucose into the bloodstream. Those that break down slowly are known as low glycemic index foods and release glucose into the bloodstream gradually. The latter can be advantageous for people with diabetes.

Examples of low glycemic index foods include:

* Fresh fruit — apples, bananas, pears, and grapes
* Breads and cereals made with whole grains
* Whole-grain hot cereals such as oatmeal
* Whole-grain pasta
* Beans
* Milk

Selecting healthy foods and monitoring food portions are important tools in managing blood glucose levels.

Eating After Training and Competition...

General sports nutrition recovery strategies are the same as for non-diabetic athletes. Fuel and fluid used during exercise need to be replaced. The increased insulin sensitivity caused by exercise lasts for several hours after exercise. Therefore the risk of hypoglycemia persists for some time. Delayed hypoglycemia can occur 4-48 hours after exercise.

Delayed hypoglycemia can be prevented by consuming sufficient carbohydrate before, during and after exercise. It may also be necessary to reduce the next insulin dose after exercise. It is helpful to monitor blood glucose levels frequently after exercise. Delayed hypoglycemia often occurs during the night. If this occurs regularly, it can intensify fatigue in athletes. Waking up feeling very tired and groggy in the morning may indicate you have experienced a 'hypo' during the night. This is a sign that you need to increase blood glucose monitoring after similar exercise sessions in the future.






Alcohol inhibits the release of glucose from the liver and therefore increases the risk of hypoglycemia. Consuming excessive alcohol also impairs the ability to recognize the symptoms of hypoglycemia. Sensible use of alcohol should be discussed with your diabetes specialist. All athletes are encouraged to moderate alcohol intake after exercise and ensure recovery needs are taken care of first.

Little research is available directly on athletes with diabetes. However, it is possible that people with Type 1 diabetes have a reduced ability to store glycogen after exercise. This may be an issue when strenuous training sessions are held within a short period of time (less than 24 hours apart).

Practical Strategies for Managing Diabetes Before, During, and After Exercise...

Before training and competing

Hydration — Start workouts and competitions fully hydrated. Consume 400–600 ml of water or sports drink (not all sports drinks are carb free) 2–3 hours before exercise. It can help make up for any fluid deficits left over from prior workouts. Also, hydration status before exercise can be monitored by checking urine color. A light-yellow color is generally consistent with adequate hydration. If urine is darker, like the color of apple juice, that’s often a sign that more fluids are needed.

Pre-exercise eating — Eat a meal 2–4 hours before training or competing. It can help top off muscle and liver glycogen fuel stores.

The meal should be composed of familiar and well-tolerated carbohydrate foods and beverages.

Slow-to-digest fatty and high-fiber foods should be avoided in the pre-exercise meal.

Carbohydrate-rich foods include pasta, rice, bread, cereal, vegetables, fruit, and dairy products such as yogurt and milk.

For some athletes, the pre-exercise meal may need to be followed up with a small snack closer to exercise.

Check blood sugar before exercise — it’s important to ensure that your blood glucose concentration is at an appropriate level before starting exercise.

Exercising with a high blood glucose concentration — hyperglycemia — disrupts normal metabolic control and will elevate glucose levels even further.

Starting with a low blood glucose level should also be avoided.

Use the table below as a guide for what to do with your monitoring result. However, you should also discuss this with your physician or sports nutritionist, since the appropriate action can be more complicated depending on what activity you are planning.


Blood glucose control is often tighter if a consistent training routine is followed. It’s more difficult in situations when the start time of a competition is unknown or the length of an event varies. Knowing about and remaining vigilant to the development of symptoms of hypo- and hyperglycemia, and regular monitoring of blood sugar, are necessary in these situations. The same is true for elevated ketones in the bloodstream and the need for monitoring urine ketone levels

Blood Glucose Levels and Strength Training

Strength-oriented exercise (e.g. lifting weights or even sports like taekwondo) generally requires short, repetitive and intensive bursts of movement. This type of exercise can trigger a hormone response known as the 'fight or flight' or 'adrenalin' response that can temporarily raise blood glucose levels.

Currently, it is not known whether this temporary hyperglycemia from weight training has any long-term effect and management of this response is difficult and still controversial.






Decreasing carbohydrate intake to avoid the anticipated hyperglycemia might jeopardize performance during exercise and increase the risk of delayed hypoglycemia after exercise.

Increasing insulin dose after exercise to reduce blood glucose concentrations may increase the risk of delayed hypoglycemia once the 'adrenalin' response has worn off.

Regular blood glucose monitoring is important to be aware of how the body responds to strength exercise. Consult your diabetes specialist if you are concerned about your blood glucose response to weight training and seek guidance on the best way for you to respond.

Is carbohydrate loading safe for people with diabetes?

The Carbohydrate Loading fact sheet on the AIS Sports Nutrition website provides general information. Carbohydrate loading is dependent on insulin availability and therefore requires good diabetic control. It is necessary to adjust insulin administration to account for the increased carbohydrate intake and the effects of an exercise decrease. Regular blood glucose monitoring is essential when carbohydrate loading. Carbohydrate loading should not be attempted if blood glucose control is poor. Seek advice from your diabetes specialist and sports dietitian if you wish to use this method.








Using a training diary...

A training diary can be a very useful tool. You can also record the results of your blood glucose testing in your diary, so you can monitor both diabetes and non-diabetes-related factors at the same time. This information allows you to identify problem areas and to take steps to rectify them. Record the information even when things are going well; that way, if you are going through not-so-good times, you can look back on strategies that have worked for you earlier.






“The difference between failure and success is doing a thing nearly right and doing a thing exactly right”.