What is Diabetes?

Diabetes is a metabolic disorder. This means that there is a problem with the way the body uses digested food. To explain what diabetes is, we must first consider what happens in normal metabolism.

In normal metabolism, starches and sugars are digested and broken down to a simple sugar, known as glucose. Glucose then passes into the bloodstream and then into cells to be used as energy.   Insulin is a hormone that allows the food to actually enter the cells.   Insulin is made by the Pancreas.

The pancreas is actually a gland organ that produces both hormones and digestive enzymes and is located in the upper abdomen beneath the stomach.  Insulin is not the only hormone produced by the Pancreas, it also produces glucagon which regulates the amount of glucose stored in the liver.  The two hormones work antagonistically – insulin will lower the amount of glucose in the blood and increase the amount stored in the liver, while glucagon will work to increase the blood sugar levels when they are insufficient.

When not enough insulin is made or the insulin is not used appropriately by the body the condition is called Diabetes Mellitus.  In diabetes the glucose accumulates in the blood and is eventually passed out in the urine, wasting an important fuel.  The accumulated blood sugar can also damage many of the body’s systems such as heart, nerves, kidneys, eyes and also blood vessels.


  • Polyuria – urination becomes more frequent when there is too much glucose in the blood.
  • Polydipsia –  excessive thirst caused by dehydration from excessive urination
  • unintentional weight loss
  • weakness and fatigue
  • Neuropathy – numbness or tingling in the extremities such as hands.
  • dry and/or itchy skin
  • infections and bruises that taking a long time to heal
  • blurred vision

Types of diabetes

There are 3 main types of diabetes, Type 1 Diabetes, Type 2 Diabetes and Gestational Diabetes:

  • Type 1 diabetes is caused by the body’s failure to produce insulin. People with Type 1 Diabetes, therefore, require daily injections of insulin to survive. Symptoms of type 1 diabetes usually develop over a short period. Type 1 diabetes can develop at any age but is most commonly diagnosed in children and young adults.
  • Type 2 Diabetes is caused by the body not producing enough insulin or not using insulin effectively. This is the most common form of diabetes and accounts for around 90% of all diabetes. People with Type 2 Diabetes are usually older than 20 and are often overweight or obese.  People with this type tend to have less symptoms of diabetes at diagnosis and, as a consequence, almost half of all people with Type 2 Diabetes are not aware that they have this life-threatening condition.
  • Gestational Diabetes refers to diabetes occurring during pregnancy. In this condition blood glucose levels rise because the body does not produce enough insulin to meet the extra demands of pregnancy. It affects less than one in 20 pregnant women and usually disappears after birth, although women with gestational diabetes are more at risk of developing Type 2 Diabetes later in life. Gestational diabetes can be treated by following a healthy diet or through diet and insulin injections.

Complications associated with diabetes

  • Cardiovascular disease (CVD).  CVD accounts for between 50% and 80% of deaths in people with diabetes. Risk factors include high blood pressure, high blood cholesterol levels and obesity. Recognition and management of these conditions can help delay or prevent heart disease in people with diabetes.
  • Diabetic neuropathy refers to nerve disorders caused by diabetes and is probably the most common diabetic complication. Studies suggest that up to 50% of people with diabetes are affected to some degree. Neuropathy can lead to sensory loss and damage to the limbs. It is also a major cause of impotence in diabetic men.
  • Diabetic retinopathy refers to damage to the retina of the eye.  Diabetic retinopathy is a leading cause of blindness and visual disability.  Research indicates that at least 90% of these new cases of diabetic retinopathy could be reduced if there was proper and vigilant treatment and monitoring of the eyes.
  • Kidney failure may be caused by diabetes which is among the leading causes of kidney failure (further details in lesson 8).
  • Problems in pregnancy and delivery as babies born to mothers with diabetes are at increased risk of problems during the pregnancy and birth.  This may include problems such as macrosomia which is a large baby for their gestational age; such babies may suffer from their own problems such as very low blood sugar levels.  By controlling glucose levels for the duration of their pregnancy, woman can control these risks.

Prevention and treatment of diabetes

  • Primary prevention:  A healthy diet and regular physical activity is vital from the prevention of Type 2 diabetes.
  • Secondary prevention:  includes early detection and good treatment. The treatment of high blood pressure and raised blood lipids, as well as the control of blood glucose levels, can substantially reduce the risk of developing complications and slow their progression.

Type 2 diabetes can sometimes be managed with diet and lifestyle measures alone, but oral medications are often required, and less frequently insulin.

Monitoring of Diabetes

People with diabetes should test their blood sugar, or glucose, levels regularly. There are two main ways of testing a person’s blood sugar level:

The traditional method of testing your blood sugar involves pricking the finger with a lancet (a small, sharp needle) and putting a drop of blood on a test strip. The strip is then placed into a meter to display the blood sugar level.  Patients may be asked to test their blood sugars at different times of the day at before and after a meal. This information will help determine the best treatment options whether it be diet, tablets or insulin. Meters can also calculate an average blood sugar level over a period of time. Meters measure blood glucose in either millimoles per litre (mmol/l) or milligrams per decilitre (mg/dl) An ideal blood sugar level will be between 4 to 7mmol/l (or 80 to 120 mg/dl) before meals and less than 10mmol/l (180mg/dl) 90 minutes after a meal.

Glycosylated hemoglobin HbA1c test is an alternative blood test which is used to monitor the patient’s average blood glucose over a period of time of 3-4 months. In general levels below 6% indicate good diabetic control. The HbA1c is a useful test for evaluating the success of diabetes treatments.

Therapeutic Nutrition and Diabetes

The overall aims of diet and lifestyle advice in diabetes is:

  • To improve blood sugar (glycaemic) control
  • To decrease in the risk of heart disease
  • To help reduce blood pressure
  • To lower lipid levels (cholesterol and triglycerides)
  • To help delay long term complications
  • To tackle obesity through diet education and weight management (5-10% weight loss if overweight) through slow steady weight loss (0.5-1.0 kg/wk)
  • To increase exercise

A Diabetic Diet Plan


Suggest the use an oat based breakfast cereal and add some fruit. Other low GI cereals include muesli and bran cereals.


Suggest the addition of baked beans to jacket potatoes. Advise to choose a soup containing lentils and other pulses and try a variety with different breads, e.g. pitta bread and bread made with mixed grains and pumpernickel.


Pasta, noodles and basmati rice are slow release starchy foods. Also advise the inclusion of more beans and pulses. People should be advised that combining foods with different GI’s alters the overall GI of a meal, so it is helpful to include a low GI food with each meal.


People should get into the habit of eating fruit as a snack. Other low GI choices include yoghurt, popcorn, rye bread and fruit loaf.

Special Diabetic Foods and Artificial Sweeteners 

There are many foods marketed specifically to people with diabetes e.g. diabetic cake, diabetic chocolate and diabetic jam. These products contain bulk sweeteners like fructose or sorbitol in place of natural sugar. The value of these products is, however, questionable. A diabetic diet can include some sugary ‘treats’ as part of a balanced diet. Diabetic foods are can also be expensive, may have a laxative effect and can still increase blood sugar. Artificial sweeteners may, on the other hand, be a useful sugar substitute for people with diabetes as well as people who are trying to lose weight.

Examples include: saccharin, neotame, aspartame, sucralose, stevia and acesulfame potassium (Ace-K) These artificial sweeteners are calorie free and can make food taste sweet without raising blood sugar levels. However it is recommended that slowly dependence on artificial sweeteners is reduced as there might be other side effects from them.

Diabetes and Weight Management 

Weight management through diet and exercise can significantly delay/reduce the risk of developing Type 2 Diabetes (potential risk reduction: over 50 per cent).

Benefits of a 10% weight loss include:

  • Reduction in mortality
  • Reduction in blood pressure
  • Reduced risk of developing diabetes
  • Reduction in blood glucose and HbA1C
  • Reduction in angina symptoms
  • Reduction in CV risk, reducing Cholesterol and triglycerides


Course extract from Nutrition for Disease Management, To see the wide range of Nutrition courses we offer please go to this Link – Nutrition Courses.