There are two forms of diabetes with the most common being type 2 diabetes. This form occurs when there is a decline in sensitivity to insulin in target tissues leading to a progressive inadequacy of insulin production. As a result of this, blood glucose levels remain high in the blood and spill over into the urine. The other form of diabetes, known as type 1 diabetes, is usually diagnosed in children or young adults and occurs when there is a destruction of insulin- producing cells in the pancreas, so the body can no longer produce insulin. People who have this form of diabetes need to inject themselves with insulin to maintain blood glucose levels within the normal range. Although there may be no cure for either type of diabetes mellitus, it is possible to control the disease and live a normal and healthy life.

 Genetic susceptibility plays an important role in the development of type 2 diabetes. Those with a family history of the disease are at a higher risk, and some ethnic groups (South Asian, African, Mexican and Native Americans) have a much higher risk of developing type 2 diabetes. However, the disturbing increase in the prevalence of type 2 diabetes in recent years in both developed and developing countries is thought to be related more to sedentary lifestyles, coupled with too high an energy consumption, which have increased overweight and obesity in the population. Although the disease can occur in people whose weight is within the normal range, obesity, particularly abdominal obesity, is a major risk factor in the development of type 2 diabetes. With the increase in prevalence of childhood obesity and inactivity, type 2 diabetes, once known as a disease of middle and old age, is now beginning to afflict younger age groups.

There have been changes in the recommended diet for people with diabetes in recent years. Flexible and less restrictive diets, similar to ones recommended for the general public, are now advised for people with diabetes. Diabetes experts now recommend that diabetics can include sugar as part of the carbohydrate allotted in their diets. People with diabetes are often advised to consume a low glycaemic index (GI) diet, ie one with foods that produce minimal fluctuations in blood glucose. It was once believed that starches, the so-called complex carbohydrates, had a lower GI than sucrose, a so-called simple sugar. However, research has shown that most sugars actually have a lower GI than cooked starch and there is often little-to-no difference between the GI of sweetened and unsweetened products. Studies have also shown that there is little variation in the GI of naturally-occurring sugars and the same sugars after refining. For these reasons, sucrose added to foods or used as a replacement for some starchy foods, can make an important contribution to the diet of diabetics by lowering the amount of fat in their diets.

Type 2 diabetics can also benefit from increasing their physical activity levels. Physical activity has a positive effect on increasing the sensitivity of tissues and cells to the hormone insulin and regular physical activity may even prevent or delay the development of diabetes.

It is increasingly recognised that avoidance of obesity by controlling energy intake (especially saturated fats) while increasing physical activity levels, and increasing the consumption of a wide range of carbohydrate containing foods can help reduce the risk of developing type 2 diabetes. Most nutrition recommendations for diabetics permit reasonable intakes of sugar in the context of a healthy balanced diet.

American Diabetes Association (2002) Evidence-Based Nutrition Principles and Recommendations for the Treatment and Prevention of Diabetes and Related Complications - Position Statement. Diabetes Care 25(1):202-212

Bell PM (1997) Dietary and lifestyle factors contributing to insulin resistance. Proceedings of the Nutrition Society 56, 263-272

FAO Food and Nutrition Paper 66 (1998) Report of the Joint FAO/WHO Expert Consultation on Carbohydrates in Human Nutrition

Miller JCB (1994) Importance of glycemic index in diabetes. American Journal of Clinical Nutrition 59(suppl): 747S-52S

Wolever TMS and Miller JCB (1995) Sugars and blood glucose control. American Journal of Clinical Nutrition 62 (suppl): 212S-27S