Diabetes mellitus is a chronic disease that causes a disruption in the production of insulin, the hormone that regulates blood sugar levels. We distinguish between 2 types of disease; type 1, when the pancreas does not produce insulin and type 2, when the effect of the produced insulin is reduced. According to data from the CroDiab Register of people suffering from diabetes, there were 310,212 people suffering from diabetes in Croatia in 2020, and the number of people suffering from diabetes is increasing every year. In this research it is evident that diabetes is a disease that affects men and women almost equally. By analyzing age, diabetes mostly affects older people, i.e. people of advanced age, and in a very small percentage under the age of 50. The distribution of respondents or patients by type of disease follows global trends in which DM1 accounts for only 10%, while the rest of the patients have DM2. People with DM2 have a problem with obesity, and only 15.6% of respondents in this study have a normal body weight. People suffering from DM1 make up 9.7% and do not have a problem with morbid obesity. The analysis of the level of Hba1c of subjects divided into the category of nutritional status showed that our thesis is not correct and in this study, the worst regulated Hba1c is found in people with 1st degree of obesity, and the best regulated is in people with 2nd degree of obesity. Such research results can be explained by the assumption that the education and intervention of the selected endocrinologist are still better results in patients who, in addition to high levels of obesity, also have worrisome meritorious medical findings. As expected, the number of comorbidities increased with body mass index, where people of normal body weight had a minimal number or no comorbidities at all, and persons with obesity of the 2nd degree and morbidly obese subjects had an average of three comorbidities with the time that they were morbidly obese. obese people had a slightly higher risk than people with 2nd degree of obesity. Research has shown that people with a healthy weight have a much better quality of life than overweight people. The quality of life moves inversely proportional to the category of obesity.