Diet and diabetes

Written by: 
Dr Sarah Brewer

Eating well with diabetes

Paying attention to your diet is important when you have diabetes. Healthy eating can help to keep your bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body., bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. fats (cholesterolA substance present in many tissues and an important constituent of cell membranes although high concentrations of a certain type of cholesterol in the blood are unhealthy. and triglycerides), weight and blood pressure within the normal range, thus reducing your long-term risk of developing diabetes-related complications.[1]

However, if you have diabetes, you do not need to follow a special 'diabetic' diet. The same healthy eating principles apply for you as for everyone else. You can continue to enjoy a wide variety of healthy foods that are high in fibre, low in fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body., and which do not contain excess sugar, refined carbohydratesA group of compounds that are an important energy source, including sugars and starch. or salt.

If you are taking glucoseA simple sugar that is an important source of energy in the body.-lowering drugs, you do need to eat regular meals - avoid skipping meals and try to spread your food intake out over the day to help control your appetite and improve your glucoseA simple sugar that is an important source of energy in the body. levels. Plan your meals in advance, and take time to sit down for meals rather than eating in haste.

If you are on insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels., it is important that you know how to balance your insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. routine with your eating and exercise habits. This is something that your healthcare providers can help you with. It's also a good idea to see a registered dietician for advice on how to eat as healthily as possible.

You'll be better equipped to eat well if you learn more about:

Carbohydrates

People with diabetes are usually advised to eat a source of starchy carbohydrate at each meal. Starchy carbohydratesA group of compounds that are an important energy source, including sugars and starch. include:

  • Rice
  • Bread and chapattis
  • New potatoes, sweet potatoes and yams
  • Pasta and noodles
  • Cereals (such as porridge oats, muesli and bran flakes).

Brown rice, wholewheat pasta and wholegrain breads - such as granary, rye, barley and pumpernickel varieties - are better choices than 'white' processed breads. This is because they contain more fibre, vitamins and minerals. Plus the carbohydrate they contain takes longer to be digested and absorbed. As a result, they have less of an impact on your bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body. levels (see Glycaemic index).

In some countries, carbohydrate intakes are counted within 'exchanges', a system to help people get the right number of calories from each of the different energy sources (for example, carbohydratesA group of compounds that are an important energy source, including sugars and starch., proteins, fats).

If you have type 2 diabetes, and are overweight, however, you may be advised to follow a high-protein, low-carbohydrate diet. Some studies have shown that people on low-carbohydrate diets lose more weight and have more favourable changes in their bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body. and fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. levels (cholesterolA substance present in many tissues and an important constituent of cell membranes although high concentrations of a certain type of cholesterol in the blood are unhealthy., triglycerides) than similar groups of people with diabetes who follow a low-fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. diet. [1] This is controversial, and it is not recommended that you try to follow this approach on your own.  Low-carbohydrate diets for people with diabetes require medical supervision as you will need to have your medication reviewed carefully to avoid experiencing hypoglycaemic attacks.

Glycaemic index (GI)

The way in which different foods affect bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body. levels is known as their glycaemic index, or GI.

A food's GI is calculated by asking volunteers to eat the amount of a particular food that contains 50g of carbohydrate. Their bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body. levels are then measured over the next two hours and changes are compared with what happens when the volunteers drink a solution containing 50g of glucoseA simple sugar that is an important source of energy in the body. (which is assigned a standard GI of 100).

A food that has a GI of 100 will therefore produce the same bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. sugar 'spike' (rise) as pure glucoseA simple sugar that is an important source of energy in the body., while a food with a GI of 50 will affect bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body. levels only half as much.

Typical GI values for common foods: [2]

Glucose 100
Cornflakes 72
White bread 71
Wholemeal bread 64
Raisins 64
Basmati white rice (boiled) 58
White spaghetti 58
Potato crisps 57
Apricots 57
Potatoes (boiled) 56
Baked beans in tomato sauce 56
Wholewheat pasta 55
Parsnips 52
Banana, ripe 51
Mango 51
Porridge oats 51
Brown rice (steamed) 50
Grapes 49
Kiwi fruit 47
Carrots 41
Orange 40
Apple 39

Very low GI foods (less than 30):

Butter, cheese, eggs, fish, grapefruit, green vegetables, meat, nuts, plums, seafood, pulses and beans (including soya beans, kidney beans), cow's milk.

  • Foods with a GI of 55 and under are classed as low GI
  • Foods with a GI of 56 to 69 are classed as medium GI
  • Foods with a GI of 70 or above are classed as high GI.

Where possible, try to select foods with a low to moderate GI, such as whole grains, vegetables and fruit. Try to limit the amount of High GI foods you eat. Research suggests that following a low GI diet can help to improve glucoseA simple sugar that is an important source of energy in the body. control in people with diabetes. [1]

Tip: on the few occasions when you eat a high GI food, combine it with a low GI food to help even out any fluctuations in your bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body. levels. For example, always eat cornflakes with milk.

The basic principles of a healthy diet

The basic principles of healthy eating follow.

Cutting back on total fat intake

In general, it is advisable to cut back on the amount of fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. you eat. This is because fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. is a denser source of energy than carbohydrate or protein, and it contributes to weight gain.

Some types of fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body., such as trans-fats and saturated fats, have also been linked with an increased risk of heart disease. To reduce your intake of these less healthy fats, cut back on the amount of butter, margarine, cheese and fatty meats that you eat. Instead, select low-fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. foods such as reduced-fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. milk, cheese and yoghurts (check their sugar content, however).

Tip: grill, steam or bake foods rather than frying or roasting them with oil. Trim visible fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. from meats and select lean cuts where possible.

Selecting healthy fats

Certain fats have a beneficial effect on health. These include monounsaturated fats (found, for example, in olive, rapeseed, avocado, almond and macadamia nut oils) and omega-3 polyunsaturated fats found mainly in oily fish (such as salmon, herring, mackerel, sardines, pilchards, fresh tuna) and in hempseed, linseed (flax) and walnut oils.

Olive oil is a component of the Mediterranean diet, which also includes plenty of fresh fruit, vegetables and oily fish. People with type 2 diabetes who increase their intake of olive oil can significantly improve their response to insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels., and the ability of their bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. vessels to dilate. [3]

In people with type 2 diabetes, following a diet high in monounsaturated fats can also improve their body weight, waist circumference, bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. pressure, 'good' HDL-cholesterolA substance that mainly exists to carry cholesterol from the circulation to the liver; commonly referred to as 'good cholesterol'. levels and fasting glucoseA simple sugar that is an important source of energy in the body. levels. [4]

A diet high in monounsaturated fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. also appears to have a beneficial effect on glucoseA simple sugar that is an important source of energy in the body. control and bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. levels in people with type 1 diabetes. [5, 6]

Eating more fruit, vegetables and pulses

Some people with diabetes worry about eating fruit because of the sugars it contains. Most fruit has a moderate to low GI value [anchor], however, as the fruit sugars present (for example, fructose) are digested and absorbed more slowly than glucoseA simple sugar that is an important source of energy in the body.. Fruit is also an excellent source of fibre, vitamins and minerals.

If you have diabetes it is important to aim for at least five servings of fruit and vegetables per day, and preferably more. But go easy on dried fruit such as raisins, dried apricots, figs and dates, all of which have a relatively high GI - enjoy a few as a healthy snack but don't tuck into handfuls.

Try to eat more pulses such as:

  • Kidney beans
  • Chickpeas
  • Butter-beans
  • Lentils.

These are a good source of protein and fibre and make an excellent alternative to meat in low-fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. vegetarian meals.

Other useful alternatives to meat include mushrooms, mycoprotein products (made from an edible fungus) and soya products (such as tofu).

Cutting down on sugary foods

It is advisable to limit your intake of table sugar and sugary foods, but you don't have to cut them out altogether.

Research suggests that table sugar (sucrose, which is digested to form glucoseA simple sugar that is an important source of energy in the body. and fructose) does not increase bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body. levels more than a portion of starch with similar calories. Some sugar can therefore be used in baking as part of a healthy diet, for example, when making bran muffins.

If you add sugar to tea or coffee, however, try to wean yourself off by slowly cutting back, as this will help you to lose weight as well as reduce your palate for sweet foods.

Artificial sweeteners such as sorbitol, xylitol and sucralose can be used to sweeten drinks but too much of some types (for example, sorbitol) can cause bowel looseness. Diet versions of squashes and fizzy drinks, which contain artificial sweeteners, are preferable to non-diet versions, though, as sugary drinks (including sweetened fruit juices) can cause a rapid rise in bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body. levels.

Tip: you don't need to buy foods marketed specifically as 'diabetic' as these are usually expensive, contain just as much fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. and calories as 'normal' versions and will still affect your bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body. levels.

Reducing your salt intake

Excessive intake of table salt (sodium chloride) can increase blood pressure in some people, which in turn increases their risk of having a heart attackThe death of a section of heart muscle caused by an interruption in its blood supply. Also called a myocardial infarction., stroke or kidney failure.

Adults should ideally consume no more than 6g of salt per day - around one level teaspoon. Most dietary salt is hidden in processed foods including canned products, ready-prepared meals, biscuits, cakes and breakfast cereals. So it's important to check labels of bought products, and avoid those containing high amounts of salt.

Avoid obviously salty foods (bacon, salted nuts, crisps) and do not add salt during cooking or at the table.  Salt is easily replaceable with herbs and spices for flavour. Where salt is essential, use mineral-rich rock salt or sea salt rather than table salt, or use a low-sodium, higher-potassium brand of salt, though sparingly.

Note: when reading labels, those giving the salt content as 'sodium' need to be multiplied by 2.5 to give the actual table salt content. For example, a serving of soup containing 0.4g sodium contains 1g salt (sodium chloride).

Drinking alcohol only in moderation

If you drink alcohol, it's important to do so in moderation. Aim to have no more than two alcoholic drinks per day for women, or three for men.  Try to have two or three alcohol-free days per week, too.

References: 
  1. Nutrition recommendations and interventions for diabetes. Link
  2. www.glycemicindex.com
  3. Diabetes and the Mediterranean diet: a beneficial effect of oleic acid on insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. sensitivity, adipocyte glucoseA simple sugar that is an important source of energy in the body. transport and endothelium-dependent vasoreactivity. Link
  4. One-year comparison of a high-monounsaturated fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. diet with a high-carbohydrate diet in type 2 diabetes. Link
  5. Beneficial effects of increasing monounsaturated fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. intake in adolescents with type 1 diabetes. Link
  6. Impact of a high-monounsaturated-fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. diet on lipidOne of a group of compounds that are an important energy source. profile in subjects with type 1 diabetes. Link