Background The role of insulin in the treatment of type II diabetes has been the subject of many debates. Exogenous insulin has been suggested to have both beneficial and detrimental effects in the health and well-being of diabetic patients ( Genuth, 1996). The beneficial effect is the result of reducing hyperglycaemia ( Henry, 1996). On the other hand, insulin treatment is considered to accelerate the development of cardiovascular disease by increasing cardiovascular disease risk factors ( Turner, 1996). Aim The aim of this retrospective review was to monitor the effect of insulin therapy on metabolic control, and in addition to monitor the contact with a dietitian on starting insulin. Methods The study involved 202 patients with type II diabetes. Group A: 149 subjects (mean age 64 years) poorly controlled patients who had switched to insulin treatment and Group B: 53 subjects (mean age 68 years) who were maintained on oral hypoglycaemic agents. All variable were collected (a) on starting insulin (or reference date) and (b) one year later. Changes within each group in glycaemic control, weight serum lipid levels and blood pressure were evaluated using Two-sample t-test assuming equal variances. Changes in the two groups were compared using the Two-sample t-test assuming unequal variances. Results Type II diabetic patients who had switched to insulin treatment had experienced a significant increase in body weight (5.4 kg) in comparison to control subjects at the year after insulin commencement. Mean HbA1c and fasting blood glucose (FBG) decreased significantly in the insulin group (from 9.9 ± 2.1 to 8.5 ± 1.6% and from 14.6 ± 5.6 to 10.3 ± 3.9 mmol L−1, respectively). In contrast no statistically significant difference was noted in the control group for either HbA1c or FBG. Blood lipids did not change significantly in either group, and blood pressure also remained statistically unchanged. 36% of the insulin treated patients had dietetic input at the time of insulin commencement. Conclusions Weight gain and improvement in glycaemic control, has been demonstrated in previous studies. Even though the current study did not show changes in lipid levels, other studies have shown a reduction in both triglyceride and cholesterol levels. The introduction of insulin treatment in individuals with poorly controlled type II diabetes appears to positively affect metabolic control. Long-term improvement in metabolic control has been shown to have many effects on the health and longevity of diabetic individuals, as has a reduction in the individual’s weight. Prospective studies in this area could fully determine the effects of insulin introduction on these variables, enabling fuller conclusions to be made with respect to longevity and future disease risks.