Type 2 diabetes can be prevented with lifestyle changes. People who are overweight and lose as little as 7 percent of their body weight and who increase physical activity (for example, walking 30 minutes per day) can decrease their risk of diabetes mellitus by more than 50%. Metformin and acarbose, drugs that are used to treat diabetes, may reduce the risk of diabetes in people with impaired glucose regulation.
Using insulin to get blood glucose levels to a healthy level is a good thing, not a bad one. For most people, type 2 diabetes is a progressive disease. When first diagnosed, many people with type 2 diabetes can keep their blood glucose at a healthy level with a combination of meal planning, physical activity, and taking oral medications. But over time, the body gradually produces less and less of its own insulin, and eventually oral medications may not be enough to keep blood glucose levels in a healthy range. 

WELL-CONTROLLED DIABETES MELLITUS: Daily blood sugar abstracted from the records of a patient whose DM is well controlled (hemoglobin A1c=6.4). The average capillary blood glucose level is 104 mg/dL, and the standard deviation is 19. Sixty-five percent of the readings are between 90 and 140 mg/dL; the lowest blood sugar is 67 mg/dL (on April 15) and the highest is about 190 (on March 21).
Your doctor will check your blood glucose levels, and if you are diagnosed with diabetes, your doctor will guide you on a plan to keep your blood sugar levels normal. If your diabetes is mild, your doctor will likely recommend a diet plan, exercise, and weight loss. Your doctor may prescribe medications that help reduce blood sugar levels. In some women, insulin may be necessary.
What is type 2 diabetes and prediabetes? Behind type 2 diabetes is a disease where the body’s cells have trouble responding to insulin – this is called insulin resistance. Insulin is a hormone needed to store the energy found in food into the body’s cells. In prediabetes, insulin resistance starts growing and the beta cells in the pancreas that release insulin will try to make even more insulin to make up for the body’s insensitivity. This can go on for a long time without any symptoms. Over time, though, the beta cells in the pancreas will fatigue and will no longer be able to produce enough insulin – this is called “beta burnout.” Once there is not enough insulin, blood sugars will start to rise above normal. Prediabetes causes people to have higher-than-normal blood sugars (and an increased risk for heart disease and stroke). Left unnoticed or untreated, blood sugars continue to worsen and many people progress to type 2 diabetes. After a while, so many of the beta cells have been damaged that diabetes becomes an irreversible condition. 
All types of diabetes mellitus have something in common. Normally, your body breaks down the sugars and carbohydrates you eat into a special sugar called glucose. Glucose fuels the cells in your body. But the cells need insulin, a hormone, in your bloodstream in order to take in the glucose and use it for energy. With diabetes mellitus, either your body doesn't make enough insulin, it can't use the insulin it does produce, or a combination of both.
Diabetes mellitus is not a single disorder but a heterogeneous group of disorders. All forms are characterized by hyperglycemia and disturbances of carbohydrate, fat, and protein metabolism which are associated with absolute or relative deficiencies of insulin action and/or insulin secretion. The World Health Organization (WHO) developed a now widely accepted classification of the disorder, largely based on clinical characteristics (see Table 1, WHO, 1985).
Jump up ^ Sarwar N, Gao P, Seshasai SR, Gobin R, Kaptoge S, Di Angelantonio E, Ingelsson E, Lawlor DA, Selvin E, Stampfer M, Stehouwer CD, Lewington S, Pennells L, Thompson A, Sattar N, White IR, Ray KK, Danesh J (June 2010). "Diabetes mellitus, fasting blood glucose concentration, and risk of vascular disease: a collaborative meta-analysis of 102 prospective studies". Lancet. 375 (9733): 2215–22. doi:10.1016/S0140-6736(10)60484-9. PMC 2904878. PMID 20609967.
The word diabetes (/ˌdaɪ.əˈbiːtiːz/ or /ˌdaɪ.əˈbiːtɪs/) comes from Latin diabētēs, which in turn comes from Ancient Greek διαβήτης (diabētēs), which literally means "a passer through; a siphon".[111] Ancient Greek physician Aretaeus of Cappadocia (fl. 1st century CE) used that word, with the intended meaning "excessive discharge of urine", as the name for the disease.[112][113] Ultimately, the word comes from Greek διαβαίνειν (diabainein), meaning "to pass through,"[111] which is composed of δια- (dia-), meaning "through" and βαίνειν (bainein), meaning "to go".[112] The word "diabetes" is first recorded in English, in the form diabete, in a medical text written around 1425.
Having diabetes requires life-long treatment and follow-up by health professionals. Diabetes can be linked to damage of the eyes, kidneys and feet. It is also associated with increased risk of strokes, heart attacks and poor blood circulation to the legs. Medical care aims to minimise these risks by controlling diabetes, blood pressure and cholesterol and screening for possible complications caused by the diabetes. 

Type 2 diabetes usually begins with insulin resistance, a condition in which muscle, liver, and fat cells do not use insulin well. As a result, your body needs more insulin to help glucose enter cells. At first, the pancreas makes more insulin to keep up with the added demand. Over time, the pancreas can’t make enough insulin, and blood glucose levels rise.
Education: People with diabetes should learn as much as possible about this condition and how to manage it. The more you know about your condition, the better prepared you are to manage it on a daily basis. Many hospitals offer diabetes education programs and many nurses and pharmacists have been certified to provide diabetes education. Contact a local hospital, doctor, or pharmacist to find out about programs and diabetes educators in your area.
Jump up ^ Attridge, Madeleine; Creamer, John; Ramsden, Michael; Cannings-John, Rebecca; Hawthorne, Kamila (2014-09-04). "Culturally appropriate health education for people in ethnic minority groups with type 2 diabetes mellitus". Cochrane Database of Systematic Reviews (9): CD006424. doi:10.1002/14651858.CD006424.pub3. ISSN 1469-493X. PMID 25188210.

All children with type 1 diabetes mellitus require insulin therapy. Most require 2 or more injections of insulin daily, with doses adjusted on the basis of self-monitoring of blood glucose levels. Insulin replacement is accomplished by giving a basal insulin and a preprandial (premeal) insulin. The basal insulin is either long-acting (glargine or detemir) or intermediate-acting (NPH). The preprandial insulin is either rapid-acting (lispro, aspart, or glulisine) or short-acting (regular).
Diabetes is a metabolic disorder that occurs when your blood sugar (glucose), is too high (hyperglycemia). Glucose is what the body uses for energy, and the pancreas produces a hormone called insulin that helps convert the glucose from the food you eat into energy. When the body does not produce enough insulin - or does not produce any at all - the glucose does not reach your cells to be used for energy. This results in diabetes.

A random blood sugar of greater than 11.1 mmol/l (200 mg/dl) in association with typical symptoms[23] or a glycated hemoglobin (HbA1c) of ≥ 48 mmol/mol (≥ 6.5 DCCT %) is another method of diagnosing diabetes.[10] In 2009 an International Expert Committee that included representatives of the American Diabetes Association (ADA), the International Diabetes Federation (IDF), and the European Association for the Study of Diabetes (EASD) recommended that a threshold of ≥ 48 mmol/mol (≥ 6.5 DCCT %) should be used to diagnose diabetes.[48] This recommendation was adopted by the American Diabetes Association in 2010.[49] Positive tests should be repeated unless the person presents with typical symptoms and blood sugars >11.1 mmol/l (>200 mg/dl).[48]

Type 2 diabetes typically starts with insulin resistance. That is, the cells of the body resist insulin’s efforts to escort glucose into the cells. What causes insulin resistance? It appears to be caused by an accumulation of microscopic fat particles within muscle and liver cells.4 This fat comes mainly from the diet—chicken fat, beef fat, cheese fat, fish fat, and even vegetable fat. To try to overcome insulin resistance, the pancreas produces extra insulin. When the pancreas can no longer keep up, blood sugar rises. The combination of insulin resistance and pancreatic cell failure leads to type 2 diabetes.
Injections of insulin may either be added to oral medication or used alone.[24] Most people do not initially need insulin.[13] When it is used, a long-acting formulation is typically added at night, with oral medications being continued.[23][24] Doses are then increased to effect (blood sugar levels being well controlled).[24] When nightly insulin is insufficient, twice daily insulin may achieve better control.[23] The long acting insulins glargine and detemir are equally safe and effective,[98] and do not appear much better than neutral protamine Hagedorn (NPH) insulin, but as they are significantly more expensive, they are not cost effective as of 2010.[99] In those who are pregnant insulin is generally the treatment of choice.[23]

Although this complication is not seen in pediatric patients, it is a significant cause of morbidity and premature mortality in adults with diabetes. People with type 1 diabetes mellitus have twice the risk of fatal myocardial infarction (MI) and stroke that people unaffected with diabetes do; in women, the MI risk is 4 times greater. People with type 1 diabetes mellitus also have 4 times greater risk for atherosclerosis.
Then, your blood sugar levels get too high. High blood sugar can have a deleterious effect on many parts of your body, including heart, blood vessels, nerves, eyes, and kidneys. Those who are overweight, don’t exercise enough, or have a history of type 2 diabetes in their family are more likely to get the disease. Maintaining a healthy weight, eating a healthy diet, and getting enough exercise can prevent type 2 diabetes. If you have a history of diabetes in your family, or if you are overweight, stay ahead of the disease by making healthy lifestyle choices and changing your diet.

Sources of complex carbohydrates include whole-wheat bread and brown rice, legumes like black beans, and quinoa. These foods contain fiber, vitamins, and minerals that are appropriate for any eating plan, regardless of whether you have prediabetes, have diabetes, or are perfectly healthy. In fact, experts know including complex carbs in your daily diet can help you maintain a healthy weight, among other health benefits.
After a diagnosis of diabetes mellitus has been made, and treatment with insulin therapy has begun, a so-called ‘honeymoon stage’ may develop. This stage is characterised by a reduction in insulin requirements which may last from weeks to months. Some patients may require no insulin at all. This stage is always transient (short-lasting) and is due to production of insulin by the remaining surviving pancreatic beta cells. Eventually, these cells will be destroyed by the on-going auto-immune process, and the patient will be dependent on exogenous (artificial) insulin.
There are many complications of diabetes. Knowing and understanding the signs of these complications is important. If caught early, some of these complications can be treated and prevented from getting worse. The best way to prevent complications of diabetes is to keep your blood sugars in good control. High glucose levels produce changes in the blood vessels themselves, as well as in blood cells (primarily erythrocytes) that impair blood flow to various organs.

Some cases of diabetes are caused by the body's tissue receptors not responding to insulin (even when insulin levels are normal, which is what separates it from type 2 diabetes); this form is very uncommon. Genetic mutations (autosomal or mitochondrial) can lead to defects in beta cell function. Abnormal insulin action may also have been genetically determined in some cases. Any disease that causes extensive damage to the pancreas may lead to diabetes (for example, chronic pancreatitis and cystic fibrosis). Diseases associated with excessive secretion of insulin-antagonistic hormones can cause diabetes (which is typically resolved once the hormone excess is removed). Many drugs impair insulin secretion and some toxins damage pancreatic beta cells. The ICD-10 (1992) diagnostic entity, malnutrition-related diabetes mellitus (MRDM or MMDM, ICD-10 code E12), was deprecated by the World Health Organization (WHO) when the current taxonomy was introduced in 1999.[53]
Excessive thirst typically goes hand-in-hand with increased urination. As your body pulls water out of the tissues to dilute your blood and to rid your body of sugar through the urine, the urge to drink increases. Many people describe this thirst as an unquenchable one. To stay hydrated, you drink excessive amounts of liquids. And if those liquids contain simple sugars (soda, sweet iced tea, lemonade, or juice, for example) your sugars will skyrocket even higher.
Doctors and people with diabetes have observed that infections seem more common if you have diabetes. Research in this area, however, has not proved whether this is entirely true, nor why. It may be that high levels of blood sugar impair your body's natural healing process and your ability to fight infections. For women, bladder and vaginal infections are especially common.
Schedule a yearly physical exam and regular eye exams. Your regular diabetes checkups aren't meant to replace regular physicals or routine eye exams. During the physical, your doctor will look for any diabetes-related complications, as well as screen for other medical problems. Your eye care specialist will check for signs of retinal damage, cataracts and glaucoma.
Hypoglycemia, or low blood sugar, can be caused by too much insulin, too little food (or eating too late to coincide with the action of the insulin), alcohol consumption, or increased exercise. A patient with symptoms of hypoglycemia may be hungry, cranky, confused, and tired. The patient may become sweaty and shaky. Left untreated, the patient can lose consciousness or have a seizure. This condition is sometimes called an insulin reaction and should be treated by giving the patient something sweet to eat or drink like a candy, sugar cubes, juice, or another high sugar snack.
DM affects at least 16 million U.S. residents, ranks seventh as a cause of death in the United States, and costs the national economy over $100 billion yearly. The striking increase in the prevalence of DM in the U.S. during recent years has been linked to a rise in the prevalence of obesity. About 95% of those with DM have Type 2, in which the pancreatic beta cells retain some insulin-producing potential, and the rest have Type 1, in which exogenous insulin is required for long-term survival. In Type 1 DM, which typically causes symptoms before age 25, an autoimmune process is responsible for beta cell destruction. Type 2 DM is characterized by insulin resistance in peripheral tissues as well as a defect in insulin secretion by beta cells. Insulin regulates carbohydrate metabolism by mediating the rapid transport of glucose and amino acids from the circulation into muscle and other tissue cells, by promoting the storage of glucose in liver cells as glycogen, and by inhibiting gluconeogenesis. The normal stimulus for the release of insulin from the pancreas is a rise in the concentration of glucose in circulating blood, which typically occurs within a few minutes after a meal. When such a rise elicits an appropriate insulin response, so that the blood level of glucose falls again as it is taken into cells, glucose tolerance is said to be normal. The central fact in DM is an impairment of glucose tolerance of such a degree as to threaten or impair health. Long recognized as an independent risk factor for cardiovascular disease, DM is often associated with other risk factors, including disorders of lipid metabolism (elevation of very-low-density lipoprotein cholesterol and triglycerides and depression of high-density lipoprotein cholesterol), obesity, hypertension, and impairment of renal function. Sustained elevation of serum glucose and triglycerides aggravates the biochemical defect inherent in DM by impairing insulin secretion, insulin-mediated glucose uptake by cells, and hepatic regulation of glucose output. Long-term consequences of the diabetic state include macrovascular complications (premature or accelerated atherosclerosis with resulting coronary, cerebral, and peripheral vascular insufficiency) and microvascular complications (retinopathy, nephropathy, and neuropathy). It is estimated that half those with DM already have some complications when the diagnosis is made. The American Diabetes Association (ADA) recommends screening for DM for people with risk factors such as obesity, age 45 years or older, family history of DM, or history of gestational diabetes. If screening yields normal results, it should be repeated every 3 years. The diagnosis of DM depends on measurement of plasma glucose concentration. The diagnosis is confirmed when any two measurements of plasma glucose performed on different days yield levels at or above established thresholds: in the fasting state, 126 mg/dL (7 mmol/L); 2 hours postprandially (after a 75-g oral glucose load) or at random, 200 mg/dL (11.1 mmol/L). A fasting plasma glucose of 100-125 mg/dL (5.5-6.9 mmol/L) or a 2-hour postprandial glucose of 140-199 mg/dL (7.8-11 mmol/L) is defined as impaired glucose tolerance. People with impaired glucose tolerance are at higher risk of developing DM within 10 years. For such people, lifestyle modification such as weight reduction and exercise may prevent or postpone the onset of frank DM. Current recommendations for the management of DM emphasize education and individualization of therapy. Controlled studies have shown that rigorous maintenance of plasma glucose levels as near to normal as possible at all times substantially reduces the incidence and severity of long-term complications, particularly microvascular complications. Such control involves limitation of dietary carbohydrate and saturated fat; monitoring of blood glucose, including self-testing by the patient and periodic determination of glycosylated hemoglobin; and administration of insulin (particularly in Type 1 DM), drugs that stimulate endogenous insulin production (in Type 2 DM), or both. The ADA recommends inclusion of healthful carbohydrate-containing foods such as whole grains, fruits, vegetables, and low-fat milk in a diabetic diet. Restriction of dietary fat to less than 10% of total calories is recommended for people with diabetes, as for the general population. Further restriction may be appropriate for those with heart disease or elevated cholesterol or triglyceride levels. The ADA advises that high-protein, low-carbohydrate diets have no particular merit in long-term weight control or in maintenance of a normal plasma glucose level in DM. Pharmaceutical agents developed during the 1990s improve control of DM by enhancing responsiveness of cells to insulin, counteracting insulin resistance, and reducing postprandial carbohydrate absorption. Tailor-made insulin analogues produced by recombinant DNA technology (for example, lispro, aspart, and glargine insulins) have broadened the range of pharmacologic properties and treatment options available. Their use improves both short-term and long-term control of plasma glucose and is associated with fewer episodes of hypoglycemia. SEE ALSO insulin resistance
This depends on the type of diabetes. Type 2 diabetes, and to a lesser extent type 1 diabetes, may run in families. If a parent has diabetes, their children will not necessarily get it but they are at an increased risk. In type 2 diabetes, lifestyle factors such as being overweight (obesity) and lack of exercise can significantly increase your risk of developing diabetes. Some rarer types of diabetes mellitus may be inherited.

Per the WHO, people with fasting glucose levels from 6.1 to 6.9 mmol/l (110 to 125 mg/dl) are considered to have impaired fasting glucose.[67] people with plasma glucose at or above 7.8 mmol/l (140 mg/dl), but not over 11.1 mmol/l (200 mg/dl), two hours after a 75 gram oral glucose load are considered to have impaired glucose tolerance. Of these two prediabetic states, the latter in particular is a major risk factor for progression to full-blown diabetes mellitus, as well as cardiovascular disease.[68] The American Diabetes Association (ADA) since 2003 uses a slightly different range for impaired fasting glucose of 5.6 to 6.9 mmol/l (100 to 125 mg/dl).[69]

Risk factors for type 2 diabetes include obesity, high cholesterol, high blood pressure, and physical inactivity. The risk of developing type 2 diabetes also increases as people grow older. People who are over 40 and overweight are more likely to develop type 2 diabetes, although the incidence of this type of diabetes in adolescents is growing. Diabetes is more common among Native Americans, African Americans, Hispanic Americans and Asian Americans/Pacific Islanders. Also, people who develop diabetes while pregnant (a condition called gestational diabetes) are more likely to develop type 2 diabetes later in life.
^ Jump up to: a b c Maruthur, NM; Tseng, E; Hutfless, S; Wilson, LM; Suarez-Cuervo, C; Berger, Z; Chu, Y; Iyoha, E; Segal, JB; Bolen, S (19 April 2016). "Diabetes Medications as Monotherapy or Metformin-Based Combination Therapy for Type 2 Diabetes: A Systematic Review and Meta-analysis". Annals of Internal Medicine. 164 (11): 740–51. doi:10.7326/M15-2650. PMID 27088241.

A proper diet and exercise are the foundations of diabetic care,[23] with a greater amount of exercise yielding better results.[80] Exercise improves blood sugar control, decreases body fat content and decreases blood lipid levels, and these effects are evident even without weight loss.[81] Aerobic exercise leads to a decrease in HbA1c and improved insulin sensitivity.[82] Resistance training is also useful and the combination of both types of exercise may be most effective.[82]

It’s not uncommon for patients to suddenly feel unsteady and immediately need to reach for carbs, says Marjorie Cypress, a nurse practitioner at an endocrinology clinic in Albuquerque, New Mexico, and 2014 president of health care and education for the American Diabetes Association. “When you have high blood sugar, your body has a problem regulating its glucose,” she explains. “If you’ve eaten something high in carbohydrates, your body shoots out a little too much insulin, and your glucose drops quickly. This makes you feel shaky, and you tend to crave carbs or sugar. This can lead to a vicious cycle.” These are the best foods for someone on a diabetic diet.
A second theory, dubbed the hygiene hypothesis, blames the rise of type 1 on a society that's too clean. Good housekeeping and hygiene habits mean far fewer interactions with germs, which in turn may foster an immune system prone to going awry. "In a developing country, you have more infectious disease. This is associated with a lower risk of type 1 diabetes," says Li Wen, MD, PhD, an immunologist at the Yale University School of Medicine. In her lab, rodents raised in hyper-clean environments are more likely to get type 1 than those reared in dirtier cages.
6. Polycystic ovary syndrome (PCOS): This is a common cause of female infertility and insulin resistance. It can cause signs and symptoms like irregular periods, acne, thinning scalp hair, and excess hair growth on the face and body. High insulin levels also increase the risk of developing diabetes, and about half of women with PCOS develop diabetes.