FOOD AND NUTRITION FOR TYPE 1 DIABETES
Healthy eating is an essential part of managing type 1 diabetes. The following facts about food and healthy eating will help you understand the requirements of a healthy food plan to maintain the balance required between food, physical activity and insulin.
The three main nutrients in food are:
Insulin is required by the body to be able to utilise these nutrients. A healthy balanced food plan will include all of these nutrients, although we require more of some than others.
Carbohydrate foods are those that contain:
Grains (wheat, rye, oats, barley), bread and breakfast cereals made with these grains, pasta, noodles, rice, legumes (dried peas, beans and baked beans, lentils), starchy vegetables (potato, kumara, corn, parsnip, yams, taro, green banana).
2. Natural sugars
Fruit, fruit juices, honey, milk, ordinary table sugar (sucrose).
3. Added sugar for sweetness
Jam, cakes, biscuits, ice cream, sweetened tinned fruit, confectionery.
When carbohydrate foods are digested, they are broken down into glucose, providing the best source of energy for the body.
Managing your diabetes involves balancing the glucose from the carbohydrate foods you eat with your physical activity and insulin.
WHAT ARE THE BEST CARBOHYDRATES?
Most carbohydrate foods are good for people with diabetes, but those rich in fibre such as wholegrain breads (breads with lots of ‘grainy’ bits), high fibre breakfast cereals, legumes, fruit and vegetables and those with low glycaemic index are better.
Carbohydrate foods that have a low glycaemic index (low GI) are more slowly digested and produce a more gradual rise in blood glucose levels, helping to sustain more even blood glucose levels.
Lower GI foods include:
- Denser wholegrain breads – Burgen, Holsom’s 9 Grain, sourdough and pumpernickel breads
- Wholegrain cereals – All-Bran, Rolled oats, Special K, untoasted, unsweetened muesli
- Rice – Basmati, Doongara, Uncle Ben’s par boiled
- Legumes – dried peas, beans and lentils
- Milk, yoghurt
- Fruit – apples, apricots, bananas, mango, orange, pears, plums, peaches
- Vegetables – corn, green banana, taro, yams
For further information on Glycaemic Index refer to:
“The New Glucose Revolution – The Glycaemic Index Solution for Optimum Health” by Prof Jennie Brand-Miller, Kaye Foster-Powell, Prof Stephen Colagiuri.
If you use a short acting insulin like Novorapid or Humalog at meals with a long acting insulin, a very low GI meal, such as a bowl of porridge for breakfast, may give you a low blood glucose level soon after your meal.
Checking your blood glucose level before and two hours after a meal will help you to understand the effect foods have on your blood glucose levels. If you do get a low blood glucose level soon after you have finished a meal, it is important to discuss this with your dietitian or health care professional.
Regular in between snacks are important for people on insulin. This is when low GI carbohydrate foods make particularly good snack choices.
Healthy lower GI snacks include:
- A slice of Burgen Mixed Fruit Loaf, or
- A pottle of low fat, diet or lite yoghurt, or
- 3 – 4 Arnott’s Vita-Wheat crispbreads, or
- A 200ml glass of low fat milk, or
- A small serve of raw fruit or 1/2 a small banana
Morning and afternoon snacks are sometimes not necessary with a rapid acting insulin, although a supper snack is always encouraged.
The need for regular snacks should to be discussed with your dietitian or health care professional.
WHAT ABOUT SUGAR?
Small amounts of sugar or added sugar can be included as part of a healthy eating pattern but are best incorporated as part of a meal.
A small amount is the equivalent of using 1 -2 teaspoons of sugar such as a scraping jam on wholegrain bread or sugar in savoury foods such as baked beans.
Foods that are very high in sugar contribute very little nutritional value, are often high in fat, and add significant extra carbohydrates to your diet. These foods will increase your blood glucose levels dramatically.
The recommendation is that these foods are best limited or used only as an occasional treat.
Foods high in sugar include: Syrups, honey, sweetened tinned fruit, cakes, puddings, sweet biscuits, sweetened condensed milk, lollies, chocolate, ice cream, cordial, soft drink, fruit juice, beer, sweet sherry, sweet wines and, of course, sugar used in excess with a meal or snack.
‘Sugar free’ products, such as biscuits and chocolate, are not necessary. They are often high in fat and very expensive.
WHAT IS A CARBOHYDRATE SERVE?
The recommended intake of carbohydrate foods is individual and will depend on your weight, age and activity level.
It is important to see a dietitian who will be able to recommend an appropriate carbohydrate intake for you. A dietitian will also teach you how to read and understand food labels, so that you are able to calculate the carbohydrate content of food.
Some examples of one carbohydrate serve:
- 1 slice of wholegrain bread, 1/2 piece of roti, or 1 small pita bread
- 1/2 cup bran cereal or 1/2 cup raw porridge oats or 1/4 cup low fat, unsweetened muesli
- 3 – 4 crispbreads or 2 plain sweet biscuits, eg: 2 gingernuts, 2 sultana fruit fingers or milk arrowroot biscuits
- 1/3 cup of cooked rice or pasta
- 1 small potato or kumara or 1/2 cup corn kernels
- 1 medium raw fruit
Carbohydrate foods help to balance your blood glucose levels. The effect of carbohydrate on blood glucose levels will depend on:
- The amount of carbohydrate eaten:
Eating a consistent amount of carbohydrate at each meal and snack will help to keep blood glucose levels more stable. Aim to choose 3 or 4 serves of carbohydrate food at each meal. A dietitian is the best person to help you work out your individual carbohydrate requirements. This will depend on your weight, activity levels, medication and blood glucose control.
- The type of carbohydrate
Choosing carbohydrate foods that are more slowly digested or have a low to moderate glycaemic index can help to maintain more even blood glucose levels.
- The timing of your meals/snacks
Eating meals and snacks at consistent times helps to keep your blood glucose levels within target range. Aim to eat something every 2 1/2 to 3 hours and main meals no longer than 4 – 5 hours apart.
- The level of physical activity
When you are more physically active you may find you need to increase your carbohydrate intake and/or adjust your insulin intake.
- How good your diabetes control is
When your diabetes is well controlled, your insulin will match the amount of carbohydrate in the food you eat and your activity, enabling you to achieve good blood glucose control.
Protein is required by the body for growth and repair of body tissues.
- Protein rich sources include:
Red meat, fish, seafood, chicken , dairy products, eggs, legumes, nuts, seeds and soy products (tofu, tempeh)
Protein foods do not directly affect blood glucose levels.
Many protein foods contain fat, so eating protein in excess will result in a higher fat intake and contribute to weight gain.
Choose lower fat varieties – lean red meats, chicken without the skin, low fat milks and yoghurts, low fat cheeses, such as edam and cottage cheese.
One to two small servings a day is all that is needed.
This is equivalent to:
- One small ‘palm’ sized piece of lean meat
- One ‘palm’ sized piece of chicken without the skin
- One ‘palm’ sized piece of fish
Fat is an important nutrient needed by the body, but only in very small amounts. All fats are high in energy (kilojoules/kilocalories), so when eaten in excess, contribute greatly to weight gain.
Fat is found in many foods.
Visible fat includes:
Fat in and around meat, skin on chicken, butter, margarine, oil, cream, sour cream, cream cheese, lard, dripping, suet, Chefade, Kremalta
Hidden fat includes:
Full cream dairy products – milk, ice cream, yoghurt, fried foods, takeaways, processed meats, pastry, pies, quiche, croissants, mayonnaise, salad dressings, many dessert foods, and snack foods such as cakes, biscuits, and chocolate .
There are three major types of fat:
- Saturated fats are found mainly in foods of animal origin such as butter, cheese, processed and fatty meats. They are also found in the tropical oils, coconut and palm oil. It is the saturated fats that are the most detrimental to our health. They decrease the effectiveness of insulin, increase blood cholesterol and increase the risk of heart disease.
- Monounsaturated fats are of vegetable origin, found in canola and olive oils, as well as margarine made from these oils, nuts and avocado.
- Polyunsaturated fats are found in vegetable oils, corn, sunflower, safflower, as well as margarine made with these oils, fish oils, nuts and seeds.
Monounsaturated and polyunsaturated fats can help lower blood cholesterol. They are protective of heart disease. Monounsaturated and polyunsaturated fats should be used in preference to saturated fat, but in small amounts.
Different carbohydrate foods have different effects on blood glucose levels.
The Glycaemic Index (GI) ranks food on a scale from 0-100 according to the effect they have on blood glucose levels. Foods with an index number of 70 or more are considered to be high GI, with an index number between 55-70 as medium GI, and 55 or less as low GI.
Foods with a high GI are those that are rapidly digested and absorbed, resulting in a rapid peak in blood glucose levels. This is not ideal for people with diabetes, who try to keep their blood glucose levels fairly stable, without rapid changes in level (peaks or troughs). By contrast, low GI foods, provided they are also low in fat, are best for controlling diabetes. This is because they produce a gradual rise in blood glucose and insulin levels because of their slow digestion, absorption, and gradual release of glucose into the bloodstream. This avoids rapid peaks and troughs.
How can the Glycaemic Index help people with diabetes?
There is evidence that a low GI diet can help control established diabetes, help people to lose weight and lower blood lipids (fats), and improve the body’s sensitivity to insulin by keeping blood glucose levels more stable than when high GI foods are consumed.
However, it is important not to eat large amounts of a food simply because it has a low GI for maintaining blood glucose levels within the ideal range.
What to consider when using the Glycaemic Index for food selection?
It’s important to remember that the GI alone should not be your only criteria when selecting what to eat. The total amount of carbohydrate, the amount and type of fat, the fibre and salt content of food are also very important.
Most importantly, you need to watch for fat content of a low GI food. Foods high in fat often have a low GI because fat slows the digestion of food. However, a diet high in fat, especially saturated fat, is not recommended for overweight people or people with diabetes.
Fibre is also frequently found in low GI foods like vegetables, fruits, legumes and many cereals. It adds bulk to a meal without calories, making us feel full as well as slowing the digestive process. These low GI foods are good to include as part of your meal.
5 simple ways to change to a low GI diet
1. Include one low GI food at each meal.
2. Switch to breakfast cereals based on barley, oats (such as porridge), wheat and rice bran.
3. Eat grainy breads made with whole seeds, barley and oats, and pumpernickel instead of white or brown bread.
4. Eat pulses and legumes (such as beans, lentils and peas).
5. Eat high fibre foods because it helps slow the digestion and absorption of carbohydrates.
For more information on the Glycaemic Index and GI values please refer to the University of Sydney’s GI website: www.glycemicindex.com