The typical symptoms of diabetes mellitus are the three “polys:” polyuria, polydipsia, and polyphagia. Because of insulin deficiency, the assimilation and storage of glucose in muscle adipose tissues, and the liver is greatly diminished. This produces an accumulation of glucose in the blood and creates an increase in its osmolarity. In response to this increased osmotic pressure there is depletion of intracellular water and osmotic diuresis. The water loss creates intense thirst and increased urination. The increased appetite (polyphagia) is not as clearly understood. It may be the result of the body's effort to increase its supply of energy foods even though eating more carbohydrates in the absence of sufficient insulin does not meet the energy needs of the cells.
Finally, modern society should probably shoulder at least some of the blame for the type 2 diabetes epidemic. Access to cheap, calorie-laden foods may even influence type 2 risk beyond simply their effects on body weight; the stuff that is in processed foods, like high-fructose corn syrup, could alter the body's chemistry or gut microbes in a way that affects health. Add to that the fact that most Americans are sedentary, spending their time sitting in cubicles, driving in cars, playing video games, or watching television. The lack of exercise, plus the abundance of unhealthy foods, cultivates a fertile breeding ground for diabetes.
When you have diabetes, it’s important to avoid eating many packaged, processed snacks such as cookies, chips, cake, granola bars, and the like, in lieu of fresh, whole foods, like fiber-rich fruits, veggies, and whole grains. (27) Eating foods high in fiber can help keep blood sugar levels steady and fill you up, potentially promoting weight loss and improving insulin sensitivity. (28)
Fatigue and muscle weakness occur because the glucose needed for energy simply is not metabolized properly. Weight loss in type 1 diabetes patients occurs partly because of the loss of body fluid and partly because in the absence of sufficient insulin the body begins to metabolize its own proteins and stored fat. The oxidation of fats is incomplete, however, and the fatty acids are converted into ketone bodies. When the kidney is no longer able to handle the excess ketones the patient develops ketosis. The overwhelming presence of the strong organic acids in the blood lowers the pH and leads to severe and potentially fatal ketoacidosis.
The American Diabetes Association sponsored an international panel in 1995 to review the literature and recommend updates of the classification of diabetes mellitus. The definitions and descriptions that follow are drawn from the Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus. The report was first approved in 1997 and modified in 1999. Although other terms are found in older literature and remain in use, their use in current clinical practice is inappropriate. Epidemiologic and research studies are facilitated by use of a common language.
Type 1 diabetes mellitus has wide geographic variation in incidence and prevalence.  Annual incidence varies from 0.61 cases per 100,000 population in China to 41.4 cases per 100,000 population in Finland. Substantial variations are observed between nearby countries with differing lifestyles, such as Estonia and Finland, and between genetically similar populations, such as those in Iceland and Norway.
Sasigarn A Bowden, MD Associate Professor of Pediatrics, Section of Pediatric Endocrinology, Metabolism and Diabetes, Department of Pediatrics, Ohio State University College of Medicine; Pediatric Endocrinologist, Associate Fellowship Program Director, Division of Endocrinology, Nationwide Children’s Hospital; Affiliate Faculty/Principal Investigator, Center for Clinical Translational Research, Research Institute at Nationwide Children’s Hospital
High blood glucose sets up a domino effect of sorts within your body. High blood sugar leads to increased production of urine and the need to urinate more often. Frequent urination causes you to lose a lot of fluid and become dehydrated. Consequently, you develop a dry mouth and feel thirsty more often. If you notice that you are drinking more than usual, or that your mouth often feels dry and you feel thirsty more often, these could be signs of type 2 diabetes.