Diabetes mellitus is a disorder in which the amount of sugar in the blood is elevated. Doctors often use the full name diabetes mellitus, rather than diabetes alone, to distinguish this disorder from diabetes insipidus. Diabetes insipidus is a relatively rare disorder that does not affect blood glucose levels but, just like diabetes mellitus, also causes increased urination.
Because type 2 diabetes is linked to high levels of sugar in the blood, it may seem logical to assume that eating too much sugar is the cause of the disease. But of course, it’s not that simple. “This has been around for years, this idea that eating too much sugar causes diabetes — but the truth is, type 2 diabetes is a multifactorial disease with many different types of causes,” says Lynn Grieger, RDN, CDE, a nutrition coach in Prescott, Arizona, and a medical reviewer for Everyday Health. “Type 2 diabetes is really complex.”

Excessive hunger goes hand-in-hand with fatigue and cell starvation. Because the cells are resistant to the body's insulin, glucose remains in the blood. The cells are then unable to gain access to glucose, which can trigger hunger hormones that tell the brain that you are hungry. Excessive eating can complicate things further by causing blood sugars to increase.

You can develop type 2 diabetes at any age, even during childhood. However, type 2 diabetes occurs most often in middle-aged and older people. You are more likely to develop type 2 diabetes if you are age 45 or older, have a family history of diabetes, or are overweight or obese. Diabetes is more common in people who are African American, Hispanic/Latino, American Indian, Asian American, or Pacific Islander.
The term "type 1 diabetes" has replaced several former terms, including childhood-onset diabetes, juvenile diabetes, and insulin-dependent diabetes mellitus (IDDM). Likewise, the term "type 2 diabetes" has replaced several former terms, including adult-onset diabetes, obesity-related diabetes, and noninsulin-dependent diabetes mellitus (NIDDM). Beyond these two types, there is no agreed-upon standard nomenclature.[citation needed]

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.
Diabetes mellitus, or simply diabetes, is a group of diseases in which a person does not produce enough insulin, or because it does not respond to the insulin that is produced. Insulin is a hormone that controls the amount of glucose (sugar) in the blood. Diabetes leads to high blood sugar levels, which can lead to damage of blood vessels, organs, and nerves.
Diabetes mellitus is a metabolic condition in which a person's blood sugar (glucose) levels are too high. Over 29.1 million children and adults in the US have diabetes. Of that, 8.1 million people have diabetes and don't even know it. Type 1 diabetes (insulin-dependent, juvenile) is caused by a problem with insulin production by the pancreas. Type 2 diabetes (non-insulin dependent) is caused by:
DKA usually follows increasing hyperglycemia and symptoms of osmotic diuresis. Users of insulin pumps, by virtue of absent reservoirs of subcutaneous insulin, may present with ketosis and more normal blood glucose levels. They are more likely to present with nausea, vomiting, and abdominal pain, symptoms similar to food poisoning. DKA may manifest as respiratory distress.

Accelerated atherosclerosis is the main underlying factor contributing to the high risk of atherothrombotic events in DM patients. CAD, peripheral vascular disease, stroke, and increased intima-media thickness are the main macrovascular complications. Diabetics are 2–4 times more likely to develop stroke than people without DM.2 CVD, particularly CAD, is the leading cause of morbidity and mortality in patients with DM.4 Patients with T2DM have a 2- to 4-fold increase in the risk of CAD, and patients with DM but without previous myocardial infarction (MI) carry the same level of risk for subsequent acute coronary events as nondiabetic patients with previous MI.5 Furthermore, people with diabetes have a poorer long-term prognosis after MI, including an increased risk for congestive heart failure and death.
Type 2 diabetes is most common is those who are genetically predisposed and who are overweight, lead a sedentary lifestyle, have high blood pressure, and/or have insulin resistance due to excess weight. People of certain ethnicities are more likely to develop diabetes, too. These include: African Americans, Mexican Americans, American Indians, Native Hawaiians, Pacific Islanders, and Asian Americans. These populations are more likely to be overweight and have high blood pressure, which increases the risk of developing diabetes.
The Diabetes Control and Complications Trial (DCCT) was a clinical study conducted by the United States National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) that was published in the New England Journal of Medicine in 1993. Test subjects all had diabetes mellitus type 1 and were randomized to a tight glycemic arm and a control arm with the standard of care at the time; people were followed for an average of seven years, and people in the treatment had dramatically lower rates of diabetic complications. It was as a landmark study at the time, and significantly changed the management of all forms of diabetes.[86][130][131]

The primary complications of diabetes due to damage in small blood vessels include damage to the eyes, kidneys, and nerves.[32] Damage to the eyes, known as diabetic retinopathy, is caused by damage to the blood vessels in the retina of the eye, and can result in gradual vision loss and eventual blindness.[32] Diabetes also increases the risk of having glaucoma, cataracts, and other eye problems. It is recommended that diabetics visit an eye doctor once a year.[33] Damage to the kidneys, known as diabetic nephropathy, can lead to tissue scarring, urine protein loss, and eventually chronic kidney disease, sometimes requiring dialysis or kidney transplantation.[32] Damage to the nerves of the body, known as diabetic neuropathy, is the most common complication of diabetes.[32] The symptoms can include numbness, tingling, pain, and altered pain sensation, which can lead to damage to the skin. Diabetes-related foot problems (such as diabetic foot ulcers) may occur, and can be difficult to treat, occasionally requiring amputation. Additionally, proximal diabetic neuropathy causes painful muscle atrophy and weakness.
; DM multiaetiology metabolic disease due to reduced/absent production of pancreatic insulin, and/or insulin resistance by peripheral tissue insulin receptors; characterized by reduced carbohydrate metabolism and increased fat and protein metabolism, leading to hyperglycaemia, increasing glycosuria, water and electrolyte imbalance, ketoacidosis, coma and death if left untreated; chronic long-term complications of DM include nephropathy, retinopathy, neuropathy and generalized degenerative changes in large and small arteries; treatment (with insulin/oral hypoglycaemic agents/diet) aims to stabilize blood glucose levels to the normal range (difficult to achieve fully; patients may tend to hyperglycaemia or hypoglycaemia due to mismanagement of glycaemic control); Tables D4-D7

The above tips are important for you. But it's also crucial to allow yourself time to cope with the diagnosis and commit to making lifestyle changes that will benefit you forever. The good news is the diabetes is a manageable disease; the tough part is that you must think about it daily. Consider finding support—someone that you can talk to about your struggles—be that a friend, another person with diabetes, or a loved one. This may seem trivial, but it truly can help you take control of diabetes so that it doesn't control you. Some next steps that may help you to get on the right track at this early stage in your journey:
Being overweight is a risk factor for developing diabetes, but other risk factors such as how much physical activity you get, family history, ethnicity, and age also play a role. Unfortunately, many people think that weight is the only risk factor for type 2 diabetes, but many people with type 2 diabetes are at a normal weight or only moderately overweight.

Over recent decades, and particularly in the past five years, researchers have found dozens of genes with links to diabetes. The count stands at about 50 genes for type 1 and 38 for type 2. The numbers have risen quickly in recent years because of advances in the gene-sequencing technology used to conduct genome-wide association studies. This technique involves taking the genetic compositions of a group of people with a disease and comparing them en masse to the genomes of people who don't have the disease.
Nerve damage from diabetes is called diabetic neuropathy and is also caused by disease of small blood vessels. In essence, the blood flow to the nerves is limited, leaving the nerves without blood flow, and they get damaged or die as a result (a term known as ischemia). Symptoms of diabetic nerve damage include numbness, burning, and aching of the feet and lower extremities. When the nerve disease causes a complete loss of sensation in the feet, patients may not be aware of injuries to the feet, and fail to properly protect them. Shoes or other protection should be worn as much as possible. Seemingly minor skin injuries should be attended to promptly to avoid serious infections. Because of poor blood circulation, diabetic foot injuries may not heal. Sometimes, minor foot injuries can lead to serious infection, ulcers, and even gangrene, necessitating surgical amputation of toes, feet, and other infected parts.
Type 2 diabetes occurs when the pancreas does not make enough insulin or the body does not use insulin properly. It usually occurs in adults, although in some cases children may be affected. People with type 2 diabetes usually have a family history of this condition and 90% are overweight or obese. People with type 2 diabetes may eventually need insulin injections. This condition occurs most commonly in people of Indigenous and African descent, Hispanics, and Asians.
Type 1 diabetes occurs because the insulin-producing cells of the pancreas (beta cells) are damaged. In type 1 diabetes, the pancreas makes little or no insulin, so sugar cannot get into the body's cells for use as energy. People with type 1 diabetes must use insulin injections to control their blood glucose. Type 1 is the most common form of diabetes in people who are under age 30, but it can occur at any age. Ten percent of people with diabetes are diagnosed with type 1.
Purified human insulin is most commonly used, however, insulin from beef and pork sources also are available. Insulin may be given as an injection of a single dose of one type of insulin once a day. Different types of insulin can be mixed and given in one dose or split into two or more doses during a day. Patients who require multiple injections over the course of a day may be able to use an insulin pump that administers small doses of insulin on demand. The small battery-operated pump is worn outside the body and is connected to a needle that is inserted into the abdomen. Pumps can be programmed to inject small doses of insulin at various times during the day, or the patient may be able to adjust the insulin doses to coincide with meals and exercise.
Type 2 diabetes was also previously referred to as non-insulin dependent diabetes mellitus (NIDDM), or adult-onset diabetes mellitus (AODM). In type 2 diabetes, patients can still produce insulin, but do so relatively inadequately for their body's needs, particularly in the face of insulin resistance as discussed above. In many cases this actually means the pancreas produces larger than normal quantities of insulin. A major feature of type 2 diabetes is a lack of sensitivity to insulin by the cells of the body (particularly fat and muscle cells).
Lifestyle factors are important to the development of type 2 diabetes, including obesity and being overweight (defined by a body mass index of greater than 25), lack of physical activity, poor diet, stress, and urbanization.[10][30] Excess body fat is associated with 30% of cases in those of Chinese and Japanese descent, 60–80% of cases in those of European and African descent, and 100% of cases in Pima Indians and Pacific Islanders.[13] Among those who are not obese, a high waist–hip ratio is often present.[13] Smoking appears to increase the risk of type 2 diabetes mellitus.[31]
They may need to take medications in order to keep glucose levels within a healthy range. Medications for type 2 diabetes are usually taken by mouth in the form of tablets and should always be taken around meal times and as prescribed by the doctor. However, if blood glucose is not controlled by oral medications, a doctor may recommend insulin injections.

Type 1 diabetes is partly inherited, with multiple genes, including certain HLA genotypes, known to influence the risk of diabetes. In genetically susceptible people, the onset of diabetes can be triggered by one or more environmental factors,[41] such as a viral infection or diet. Several viruses have been implicated, but to date there is no stringent evidence to support this hypothesis in humans.[41][42] Among dietary factors, data suggest that gliadin (a protein present in gluten) may play a role in the development of type 1 diabetes, but the mechanism is not fully understood.[43][44]

You have a higher risk of type 2 diabetes if you are older, have obesity, have a family history of diabetes, or do not exercise. Having prediabetes also increases your risk. Prediabetes means that your blood sugar is higher than normal but not high enough to be called diabetes. If you are at risk for type 2 diabetes, you may be able to delay or prevent developing it by making some lifestyle changes.
Diabetes insipidus is considered very rare in less 20,000 cases diagnosed per year. Diabetes mellitus is more common, with type 2 diabetes being more common than type 1. There are more than 3 million cases of type 2 diabetes. Unlike diabetes mellitus, diabetes insipidus is not treated by controlling insulin levels. Depending on your symptoms, your doctor may prescribe a low-salt diet, hormone therapy, or have you increase your water intake. 

Being too heavy gets the bulk of the blame for triggering type 2 diabetes. According to the National Institutes of Health, about 85 percent of people with type 2 diabetes are overweight or obese. But consider that the remaining 15 percent are not. Consider, too, that roughly two-thirds of overweight people and a third of those who are obese will never develop diabetes. In other words, normal-weight and thin people also develop type 2, while heavy people won't necessarily. Clearly, there is more to the connection between lifestyle and type 2 diabetes than just body size.
Diabetes means your blood glucose, or blood sugar, levels are too high. With type 2 diabetes, the more common type, your body does not make or use insulin well. Insulin is a hormone that helps glucose get into your cells to give them energy. Without insulin, too much glucose stays in your blood. Over time, high blood glucose can lead to serious problems with your heart, eyes, kidneys, nerves, and gums and teeth.
Diabetes mellitus is a chronic disease caused by inherited and/or acquired deficiency in production of insulin by the pancreas, or by the ineffectiveness of the insulin produced. Such a deficiency results in increased concentrations of glucose in the blood, which in turn damage many of the body's systems, in particular the blood vessels and nerves.
Diabetic neuropathy is probably the most common complication of diabetes. Studies suggest that up to 50% of people with diabetes are affected to some degree. Major risk factors of this condition are the level and duration of elevated blood glucose. Neuropathy can lead to sensory loss and damage to the limbs. It is also a major cause of impotence in diabetic men.
As of 2015, an estimated 415 million people had diabetes worldwide,[8] with type 2 DM making up about 90% of the cases.[16][17] This represents 8.3% of the adult population,[17] with equal rates in both women and men.[18] As of 2014, trends suggested the rate would continue to rise.[19] Diabetes at least doubles a person's risk of early death.[2] From 2012 to 2015, approximately 1.5 to 5.0 million deaths each year resulted from diabetes.[8][9] The global economic cost of diabetes in 2014 was estimated to be US$612 billion.[20] In the United States, diabetes cost $245 billion in 2012.[21]

If eaten as part of a healthy meal plan, or combined with exercise, sweets and desserts can be eaten by people with diabetes. They are no more "off limits" to people with diabetes than they are to people without diabetes. The key to sweets is to have a very small portion and save them for special occasions so you focus your meal on more healthful foods.

While there is a strong genetic component to developing this form of diabetes, there are other risk factors - the most significant of which is obesity. There is a direct relationship between the degree of obesity and the risk of developing type 2 diabetes, and this holds true in children as well as adults. It is estimated that the chance to develop diabetes doubles for every 20% increase over desirable body weight.
Diet and moderate exercise are the first treatments implemented in diabetes. For many Type II diabetics, weight loss may be an important goal in helping them to control their diabetes. A well-balanced, nutritious diet provides approximately 50-60% of calories from carbohydrates, approximately 10-20% of calories from protein, and less than 30% of calories from fat. The number of calories required by an individual depends on age, weight, and activity level. The calorie intake also needs to be distributed over the course of the entire day so surges of glucose entering the blood system are kept to a minimum.
In this health topic, we discuss hyperglycemic hyperosmolar nonketotic syndrome (HHNS), an extremely serious complication that can lead to diabetic coma and even death in type 2 diabetes. This serious condition occurs when the blood sugar gets too high and the body becomes severely dehydrated. To prevent HHNS and diabetic coma in type 2 diabetes, check your blood sugar regularly as recommended by your health care provider; check your blood sugar more frequently when you are sick, drink plenty of fluids, and watch for signs of dehydration.