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.”
There is strong evidence that the long-term complications are related to the degree and duration of metabolic disturbances.2 These considerations form the basis of standard and innovative therapeutic approaches to this disease that include newer pharmacologic formulations of insulin, delivery by traditional and more physiologic means, and evolving methods to continuously monitor blood glucose to maintain it within desired limits by linking these features to algorithm-driven insulin delivery pumps for an “artificial pancreas.”
Exercise. A program of regular exercise gives anyone a sense of good health and well-being; for persons with diabetes it gives added benefits by helping to control blood glucose levels, promoting circulation to peripheral tissues, and strengthening the heart beat. In addition, there is evidence that exercise increases the number of insulin receptor sites on the surface of cells and thus facilitates the metabolism of glucose. Many specialists in diabetes consider exercise so important in the management of diabetes that they prescribe rather than suggest exercise.

People with diabetes can benefit from education about the disease and treatment, good nutrition to achieve a normal body weight, and exercise, with the goal of keeping both short-term and long-term blood glucose levels within acceptable bounds. In addition, given the associated higher risks of cardiovascular disease, lifestyle modifications are recommended to control blood pressure.[80][81]
Some older people cannot control what they eat because someone else is cooking for them—at home or in a nursing home or other institution. When people with diabetes do not do their own cooking, the people who shop and prepare meals for them must also understand the diet that is needed. Older people and their caregivers usually benefit from meeting with a dietitian to develop a healthy, feasible eating plan.
Heart disease accounts for approximately 50% of all deaths among people with diabetes in industrialized countries. Risk factors for heart disease in people with diabetes include smoking, high blood pressure, high serum cholesterol and obesity. Diabetes negates the protection from heart disease which pre-menopausal women without diabetes experience. Recognition and management of these conditions may delay or prevent heart disease in people with diabetes.
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.”
Part of a treatment plan for diabetes will involve learning about diabetes, how to manage it, and how to prevent complications. Your doctor, diabetes educator, or other health care professional will help you learn what you need to know so you are able to manage your diabetes as effectively as possible. Keep in mind that learning about diabetes and its treatment will take time. Involving family members or other people who are significant in your life can also help you manage your diabetes.
Along with following your diabetes care plan, you may need diabetes medicines, which may include pills or medicines you inject under your skin, such as insulin. Over time, you may need more than one diabetes medicine to manage your blood glucose. Even if you don’t take insulin, you may need it at special times, such as during pregnancy or if you are in the hospital. You also may need medicines for high blood pressure, high cholesterol, or other conditions.
Diabetic ketoacidosis can be caused by infections, stress, or trauma, all of which may increase insulin requirements. In addition, missing doses of insulin is also an obvious risk factor for developing diabetic ketoacidosis. Urgent treatment of diabetic ketoacidosis involves the intravenous administration of fluid, electrolytes, and insulin, usually in a hospital intensive care unit. Dehydration can be very severe, and it is not unusual to need to replace 6-7 liters of fluid when a person presents in diabetic ketoacidosis. Antibiotics are given for infections. With treatment, abnormal blood sugar levels, ketone production, acidosis, and dehydration can be reversed rapidly, and patients can recover remarkably well.
Does having type 2 diabetes affect life expectancy? While continued improvements in therapies and care for type 2 diabetes may be helping patients live longer, the unfortunate reality is that type 2 diabetes has been shown to decrease life expectancy by up to ten years, according to Diabetes UK. There is still much to be done to ensure that all patients have access to appropriate healthcare and treatments to live a happier and healthier life with type 2 diabetes.
Environmental factors are important, because even identical twins have only a 30-60% concordance for type 1 diabetes mellitus and because incidence rates vary in genetically similar populations under different living conditions. [25] No single factor has been identified, but infections and diet are considered the 2 most likely environmental candidates.
Can type 2 diabetes be prevented? It is possible to reduce the risk of developing type 2 diabetes, although the underlying risk of type 2 diabetes depends strongly on genetic factors. But there was less type 2 diabetes around some years ago when people had a more active life and didn’t eat a modern Western diet. So it is fair to say that risk of getting type 2 diabetes is based on a genetic predisposition that is aggravated by lifestyle. Type 2 diabetes is associated with obesity, as well as a variety of environmental factors. To lower the risk of developing type 2 diabetes (as well as other diseases), it is highly recommended to exercise often, eat healthily, and maintain a healthy weight. 
Insulin is released into the blood by beta cells (β-cells), found in the islets of Langerhans in the pancreas, in response to rising levels of blood glucose, typically after eating. Insulin is used by about two-thirds of the body's cells to absorb glucose from the blood for use as fuel, for conversion to other needed molecules, or for storage. Lower glucose levels result in decreased insulin release from the beta cells and in the breakdown of glycogen to glucose. This process is mainly controlled by the hormone glucagon, which acts in the opposite manner to insulin.[61]
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]
When it comes to diabetes, there's no real answer yet. Yes, science has begun to uncover the roots of this disease, unearthing a complex interplay of genes and environment—and a lot more unanswered questions. Meanwhile, there's plenty of misinformation to go around. (How often have you had to explain that diabetes doesn't happen because someone "ate too much"?)
FIGURE 19-1 ■. This figure shows the hyperbolic relationship of insulin resistance and beta cell function. On the y-axis is beta cell function as reflected in the first-phase insulin response during intravenous (IV) glucose infusion; on the x-axis is insulin sensitivity and its mirror image resistance. In a subject with normal glucose tolerance (NGT) and beta-cell reserve, an increase in insulin resistance results in increased insulin release and normal glucose tolerance. In an individual for whom the capacity to increase insulin release is compromised, increasing insulin resistance with partial or no beta-cell compensation results in progression from normal glucose tolerance, to impaired glucose tolerance (IGT), and finally to diabetes (T2D). Differences between these categories are small at high insulin sensitivity, which may be maintained by weight reduction, exercise, and certain drugs. At a critical degree of insulin resistance, due to obesity or other listed factors, only a further small increment in resistance requires a large increase in insulin output. Those that can increase insulin secretion to this extent retain normal glucose tolerance; those who cannot achieve this degree of insulin secretion (e.g., due to a mild defect in genes regulating insulin synthesis, insulin secretion, insulin action, or an ongoing immune destruction of beta cells) now unmask varying degrees of carbohydrate intolerance. The product of insulin sensitivity (the reciprocal of insulin resistance) and acute insulin response (a measurement beta-cell function) has been called the “disposition index.” This index remains constant in an individual with normal beta cell compensation in response to changes in insulin resistance. IGT, impaired glucose tolerance; NGT, normal glucose tolerance; T2D, type 2 diabetes.
As with many conditions, treatment of type 2 diabetes begins with lifestyle changes, particularly in your diet and exercise. If you have type 2 diabetes, speak to your doctor and diabetes educator about an appropriate diet. You may be referred to a dietitian. It is also a good idea to speak with your doctor before beginning an exercise program that is more vigourous than walking to determine how much and what kind of exercise is appropriate.
While there are competing explanations of the link between obesity and type 2 diabetes, Gerald Shulman, MD, PhD, a professor of internal medicine and physiology at Yale University, believes the key is figuring out insulin resistance. He has studied the causes of insulin resistance for 25 years and thinks he may have the answer to the weight-diabetes link.
gestational diabetes diabetes mellitus with onset or first recognition during pregnancy, usually during the second or third trimester. In some cases mild, undetected glucose intolerance was present before pregnancy. It often disappears after the end of the pregnancy, but many women with this condition develop permanent diabetes mellitus in later life. Although the disordered carbohydrate metabolism is usually mild, prompt detection and treatment are necessary to avoid fetal and neonatal morbidity and mortality.
As of 2016, 422 million people have diabetes worldwide,[101] up from an estimated 382 million people in 2013[17] and from 108 million in 1980.[101] Accounting for the shifting age structure of the global population, the prevalence of diabetes is 8.5% among adults, nearly double the rate of 4.7% in 1980.[101] Type 2 makes up about 90% of the cases.[16][18] Some data indicate rates are roughly equal in women and men,[18] but male excess in diabetes has been found in many populations with higher type 2 incidence, possibly due to sex-related differences in insulin sensitivity, consequences of obesity and regional body fat deposition, and other contributing factors such as high blood pressure, tobacco smoking, and alcohol intake.[102][103]
There is evidence that certain emotions can promote type 2 diabetes. A recent study found that depression seems to predispose people to diabetes. Other research has tied emotional stress to diabetes, though the link hasn't been proved. Researchers speculate that the emotional connection may have to do with the hormone cortisol, which floods the body during periods of stress. Cortisol sends glucose to the blood, where it can fuel a fight-or-flight response, but overuse of this system may lead to dysfunction.
FIGURE 19-1 ■. This figure shows the hyperbolic relationship of insulin resistance and beta cell function. On the y-axis is beta cell function as reflected in the first-phase insulin response during intravenous (IV) glucose infusion; on the x-axis is insulin sensitivity and its mirror image resistance. In a subject with normal glucose tolerance (NGT) and beta-cell reserve, an increase in insulin resistance results in increased insulin release and normal glucose tolerance. In an individual for whom the capacity to increase insulin release is compromised, increasing insulin resistance with partial or no beta-cell compensation results in progression from normal glucose tolerance, to impaired glucose tolerance (IGT), and finally to diabetes (T2D). Differences between these categories are small at high insulin sensitivity, which may be maintained by weight reduction, exercise, and certain drugs. At a critical degree of insulin resistance, due to obesity or other listed factors, only a further small increment in resistance requires a large increase in insulin output. Those that can increase insulin secretion to this extent retain normal glucose tolerance; those who cannot achieve this degree of insulin secretion (e.g., due to a mild defect in genes regulating insulin synthesis, insulin secretion, insulin action, or an ongoing immune destruction of beta cells) now unmask varying degrees of carbohydrate intolerance. The product of insulin sensitivity (the reciprocal of insulin resistance) and acute insulin response (a measurement beta-cell function) has been called the “disposition index.” This index remains constant in an individual with normal beta cell compensation in response to changes in insulin resistance. IGT, impaired glucose tolerance; NGT, normal glucose tolerance; T2D, type 2 diabetes.
“I don’t think that anybody has put their finger on what the true cause of diabetes is, or that we’re going to find a single cause,” Grieger says. So if you’ve been diagnosed with prediabetes or have other risk factors for the disease, avoiding any one food group entirely — even sugar — won’t completely offset your risk. Rather, it’s important to prioritize proper nutrition, exercise regularly, and maintain a healthy weight — all steps the American Diabetes Association recommends for preventing type 2 diabetes.
Supporting evidence for Shulman's theory comes from observations about a rare genetic illness called lipodystrophy. People with lipodystrophy can't make fat tissue, which is where fat should properly be stored. These thin people also develop severe insulin resistance and type 2 diabetes. "They have fat stored in places it doesn't belong," like the liver and muscles, says Shulman. "When we treat them . . . we melt the fat away, reversing insulin resistance and type 2 diabetes." Shulman's theory also suggests why some people who carry extra fat don't get type 2. "There are some individuals who store fat [under the skin] who have relatively normal insulin sensitivity, a so-called fit fat individual," he says. Because of the way their bodies store fat, he believes, they don't get diabetes.
Test Your Blood Sugar: Blood sugar testing is an important part of helping to manage your diabetes. Whether you choose to do selective blood sugar testing or test your blood sugar at the same times daily, blood sugar testing gives you another piece of information and can help you change your diet and adjust your fitness routine or medicines. Keeping your blood sugars at target will help to reduce diabetes complications.
Diabetes is a condition in which the body cannot properly store and use fuel for energy. The body's main fuel is a form of sugar called glucose, which comes from food (after it has been broken down). Glucose enters the blood and is used by cells for energy. To use glucose, the body needs a hormone called insulin that's made by the pancreas. Insulin is important because it allows glucose to leave the blood and enter the body's cells.
Rates of type 2 diabetes have increased markedly since 1960 in parallel with obesity.[17] As of 2015 there were approximately 392 million people diagnosed with the disease compared to around 30 million in 1985.[11][18] Typically it begins in middle or older age,[6] although rates of type 2 diabetes are increasing in young people.[19][20] Type 2 diabetes is associated with a ten-year-shorter life expectancy.[10] Diabetes was one of the first diseases described.[21] The importance of insulin in the disease was determined in the 1920s.[22]
It is important to record blood glucose readings taken at different times of the day – after fasting (before breakfast) as well as 2 hours after a meal. This allows your doctor to see a snapshot of how your blood glucose levels vary during the day and to recommend treatments accordingly. Most blood glucose meters now have "memory" that stores a number of blood glucose tests along with the time and date they were taken. Some even allow for graphs and charts of the results to be created and sent to your phone.
Type 1 diabetes mellitus is predominantly a disease of the young, usually developing before 20 years of age. Overall, type I DM makes up approximately 15% of all cases of diabetes. It develops in approximately 1 in 600 children and is one of the most common chronic diseases in children. The incidence is relatively low for children under the age of 5, increases between 5 and 15, and then tapers off.
Because both yeast and bacteria multiply more quickly when blood sugar levels are elevated, women with diabetes are overall at a higher risk of feminine health issues, such as bacterial infections, yeast infections, and vaginal thrush, especially when blood sugar isn't well controlled. And a lack of awareness about having prediabetes or diabetes can make managing blood sugar impossible.
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