How Obesity Increases Risk of Type 2 Diabetes

Accepted facts

Currently, 90% of adults with type 2 diabetes are overweight or obese making obesity the number one preventable cause of diabetes. The link between visceral obesity and diabetes 2 stands established.

Without a healthy diet and proper exercise, obesity can lead to type 2 diabetes within a short period of time in most people.

Obese people have excess adipose tissue (stored fat) around the abdomen. Fat cells are more insulin resistant than muscle cells. This simply means that fat cells are not easily receptive to the action of insulin.

Insulin is the hormone secreted by the beta cells of the pancreas, which makes the body cells take up glucose from the blood, for energy. This helps to maintain healthy sugar levels.

Due to insulin resistance, blood sugar builds up and there is more insulin secretion by the pancreas to fight the extra sugar levels. As a result, insulin secretion is very high in obese people.

Excess weight is established in the pathogenesis of type 2 diabetes. Most people with diabetes type 2 are obese, yet many obese people, despite being insulin resistant, do not develop diabetes. That is because the pancreas is still functioning well and keep on secreting adequate insulin.

Pathophysiology                                                                                                                      

Both diabetes type 2 and obesity are associated with insulin resistance. As long as the pancreas is able to cope up with increased insulin secretion to fight the insulin resistance, sugar levels stay within the normal limits.

In obese individuals, there is an increased amount of nonesterified fatty acids, glycerol, hormones, cytokines, proinflammatory markers, and other substances.

These are the very substances that are involved in the development of insulin resistance and lack of glucose uptake by the body cells.

Over time, due to excess strain, the overworked β-islet cells of the pancreas, which produce the insulin start tiring out and are unable to produce the extra insulin required to fight the rising glucose levels.

Once the pancreas tires out, insulin secretion is not enough to take care of the sugar levels resulting in hyperglycemia.

The pathophysiology in the development of diabetes type 2 is based on the fact that the body is unable to control sugar levels.

In obese people, you, therefore, have a failure of the beta cells of the pancreas accompanied by insulin resistance, making diabetes type 2 inevitable.

Obesity is linked to diabetes type 2, which is caused by insulin resistance or glucose intolerance.

Diabetes type 1 is caused by the failure of the pancreas to produce insulin only. You will find that patients with type 1 diabetes are generally not obese.

Insulin resistance, in short, means that your body cells do not take up blood sugar because they become resistant or insensitive to the action of insulin.

Due to insulin resistance, more insulin is required to maintain blood sugar levels. The pancreas copes up with this additional requirement by producing more insulin and normal sugar levels are maintained. This can last for years.

Once the pancreas cannot cope with producing this additional requirement of insulin, blood sugar begins to rise and diabetes type 2 develops. The failure of the pancreas to produce enough insulin is due to impairment of the function of the overworked beta cells of the pancreas.

Blood sugar levels are then not controlled because of insulin resistance. In an obese diabetic, controlling blood sugar needs an aggressive treatment.

If you are diabetic, you will require more insulin to promote uptake of blood glucose by the body cells. If you are not diabetic, the prolonged effect of insulin resistance can cause diabetes.

Diabetes Type 2 is a diabetes of adulthood but is seen now more amongst the young due to the increased incidence of childhood obesity. The high calorie and high carbohydrate diet of the obese only accentuates the situation. In the obese, diabetes has become almost synonymous with obesity.

There is a seven times greater risk of diabetes type 2 in centrally obese people as compared to those with a healthy weight, and a threefold increase in diabetes risk in people who are overweight but not obese.

Why obese people develop insulin resistance?

In obese people, the adipose tissue secretes more nonesterified fatty acids (NEFAs). Over time, this increased secretion of NEFAs leads to insulin resistance.

Randle et al first suggested more than 40 years ago, that obesity-associated insulin resistance is caused by intracellular competition between the increased circulating NEFAs and glucose for uptake and metabolism in the insulin-responsive cells.

Another crucial factor that determines insulin resistance is body fat distribution. Peripheral body fat (Fat around the hips and no large tummy) does not carry as much health risks as having central or visceral fat, where the fat is deposited in the abdomen and chest.

Abdominal fat easily breaks down and releases NEFAs and such fatty acids and do not react easily to the antilipolytic action of insulin. That makes abdominal fat very responsible for causing insulin insensitivity.

Obesity and diabetes statistics

Worldwide

Globally, over the last forty years, there has been a dramatic rise in the number of people with obesity and also those suffering from diabetes mellitus. Add to it the fact that 90% of the type 2 diabetics are overweight or obese and an established reality that obesity is the number preventable one cause of diabetes type 2.

Obesity has an alarming increase of its cases worldwide to its credit. It has been declared a global epidemic in most countries of the world. Consequently, diabetes cases have proportionately increased and both these conditions show no signs of slowing down.

In 1975, there were 104 million obese people worldwide. Through the forty years, that figure rose to 641 million in 2014 – a startling six-time escalation. Obese men tripled and women more than doubled.

Since 1980 till 2014, the number of adult cases who developed diabetes rose four times.

America

There are 25.8 million people with diabetes in the United States and 95% of them are people with type 2 diabetes.

Of these, 90 percent are overweight or obese making excess weight an independent and most common risk diabetes factor.

According to a study in The Journal of the American Medical Association (JAMA), and confirmed by the CDC, roughly one-third of the population of the United States is overweight and another one-third is obese.

You can see that both obesity and diabetes have attained epidemic proportions and this rise in type 2 diabetes cases across the country is associated with higher obesity rates.

U.K.

The figures in the United Kingdom present a somewhat similar picture. Prevalence of both obesity and diabetes is rising.

62% of the national adult population is overweight or obese and 90% of the type 2 diabetics are obese.

As of 2013, 6 percent of the adult population of England (or 2.7 million people) had confirmed diabetes; an increase of 134,000 people since the previous year. 12.4% of those were obese.

Approximately, one-third of the rise in diabetes cases in U.K. is attributed to obesity.
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