Although there are differences in treatment for Type 1 and Type 2 diabetes, the dietary advice for managing both types is the same.
Much has been written on what type of diet is best for diabetes, to the extent that it can all seem a bit daunting.
Although a carbohydrate-controlled diet used to be suggested, there is now no special diabetes diet.
Instead your diet should be based on the same principles of healthy eating that everyone should follow.
Why is diet important in diabetes?
Excess body weight is associated with:
- hypertension (high blood pressure)
- Type 2 diabetes
- increased risk of cardiovascular disease, eg heart attack, stroke, angina.
Diabetes, particularly Type 2, is easier to control when your weight is normal - in BMI terms, between 20 and 25.
If you have Type 1 diabetes, controlling your weight through a healthy diet will help your blood pressure and reduce your risk of cardiovascular disease.
Why was there a special diet for diabetes?
Glucose (sugar) is a carbohydrate. Because controlling blood sugar controls diabetes, a lot of dietary advice used to be given on the amount and timing of carbohydrate intake.
Carbohydrate foods were allocated a value per portion, called the exchange. A diabetic diet was constructed around the number of exchanges of carbohydrate a food contained.
For example, a thin slice of wholemeal bread contains 10g carbohydrate and is one portion or exchange. An individual might be on 200g carbohydrate, which would contain 20 exchanges in the whole day.
Although diabetes means you'll always need to take that little extra care about what you eat, modern thinking has moved away from this type of diet.
This is because all foods have an energy value, not just carbohydrate. Protein and fat are partly converted to glucose in the body, so their effect on the blood sugar level needs to be taken into account.
And different carbohydrates affect the blood glucose level at different rates:
- pure glucose is absorbed very quickly and causes blood sugar to rise within minutes.
- starchy foods are carbohydrate, but are absorbed far more slowly and release the sugar slowly over a longer period of time.
A healthy diet is a balanced diet - focusing on carbohydrates alone skews that balance.
Are calories important?
There is a common myth that people with diabetes people need to watch their calories more than the average person.
This is only partly correct. Everyone's calorie intake should be appropriate for their level of activity, regardless of whether diabetes is present.
The difference is that people who don't have diabetes still have the capacity to overcome excesses in their diet by producing extra insulin to maintain blood sugar at a normal level.
So your calorie intake only needs reducing if you need to lose weight - if your BMI is higher than 25.
Even so, weight-loss should be at a steady rate of 0.5kg (1-2lb) per week. This means you need to reduce your calorie intake by 3500 calories overall - 500 calories a day.
A good rule of thumb is to burn an extra 250 calories a day through exercise, and eat 250 calories less per day by reducing the amount of fat and sugary foods in your diet.
What are the principles of healthy eating for diabetes?
1. Eat regular meals
Starchy foods such as potatoes, pasta, bread, rice and cereals release their energy slowly because they need to be digested first.
This means they don't cause high surges of sugar in your blood in the same way that sugary foods do.
2. Cut down on high sugar foods
Foods with sugar (sucrose or glucose) require little or no digestion for your body to absorb the sugars.
This means they cause blood glucose to rise quickly after a meal.
Normally the pancreas produces a boost of insulin to cope with the raised blood sugar, but in diabetes this process fails.
So moderating the amount of high sugar foods in your diet will help control your blood sugar level.
3. Reduce the amount of fat in your diet
Compared to the other main nutrients carbohydrate and protein, fat has the most amount of calories - 9 calories per gram.
This means cutting down the amount of fat you eat will have the most effect on reducing your total calorie count.
Regardless of its role in weight loss, reducing fat intake - especially hard fats from meat - is an essential part of managing cholesterol levels and lowering your risk of heart disease.
You can reduce fat by grilling, steaming or microwaving foods and buying lean cuts of meat - for example chicken breast without the skin.
When you do use oil, use one that is high in 'good' fat such as olive oil, but use it sparingly. A spray oil is a good way to control fat in cooking.
Low-fat choices are easy to find in supermarkets, but be careful of this label. Reduced fat crisps may be lower in fat than a standard bag, but they are by no means a low-fat food.
Instead, you would be better off choosing a different type of snack altogether eg a piece of fruit.
5. Cut down salt intake
Six grams of salt or less a day is the recommended amount for adults. This equates to a slightly heaped teaspoon.
The problem is that even if you don't add salt to any of the food you eat, the amount of 'hidden' salt in processed and packaged foods means you can easily eat two to four times this daily limit. For example, a single slice of bread can contain 0.5g of salt.
Common salt is sodium chloride. On food labels, the salt content is often given as grams of sodium. To convert sodium to grams of salt, multiply the quantity of sodium by 2.5. The daily limit is about 2.5g of sodium.
Don't forget the amount stated on the label is often per 100g, not for the product itself. A standard ready meal weighs about 500g, so at 0.5g sodium per 100g it would contain 2.5g sodium - your total daily intake.
You can reduce levels of salt in your diet by:
- not adding salt to meals
- limiting the amount used in cooking
- choosing foods that contain 0.1g sodium or less per 100g - three quarters of the salt we eat comes from foods we buy
- switching everyday foods to low-sodium/reduced salt options - this means breakfast cereal, soup, biscuits, tinned vegetables and ready meals
- limiting salty foods such as crisps, salted nuts, bacon, cheese, pickles and smoked fish
- using more herbs, spices and ground pepper.
6. Moderate alcohol
Drinking up to two units of alcohol a day appears to have a beneficial effect on cardiovascular risk.
It's thought that compounds within some alcoholic drinks, particularly red wine, mop up 'free radical' molecules that can cause tissue damage.
But these benefits rapidly turn to negatives when higher levels of alcohol are consumed.
In diabetes alcohol can also lower the blood glucose level. This makes a hypoglycaemic reaction more likely - as does drinking on an empty stomach.
The recommended limits for alcohol consumption are:
- 14 units per week for women
- 21 units per week for men
A unit of alcohol is:
- 250ml (1/2 pint) of ordinary strength beer or lager
- A 125ml glass of wine
- A pub measure of sherry or vermouth (25ml)
- A pub measure of spirits (25ml).
How can I make sure I have a good diet?
If you have diabetes, you should have access to a qualified dietician through your GP or diabetes clinic.
Your dietician will help you work out your daily calorie needs, taking into account your age, lifestyle, work and activity levels.
Your dietician will identify any problems with your diet and is there to help if you're having difficulties.
Most of all, your dietician will help you understand the relationship between what you eat and what you need - once you understand this, the diet aspect of diabetes will fall into place.
