DIABETES AND OBESITY | Added: 12, August 2017


In general, what is obesity?

According to the Centers for Disease Control and Prevention, in general, obesity results when a person’s body fat accumulates over time, mainly as a result of what is called a chronic energy imbalance. In other words, the calories consumed exceed the calories expended in such activities as exercise. Obesity is a major health hazard worldwide. It is also extremely costly, as it is associated with workplace absenteeism, mainly because of obesity’s association with other diseases, such as diabetes, hypertension, heart disease, and some cancers. Of course, eating is only part of the story when it comes to obesity. Other conditions may exist, such as thyroid disease, genetic predisposition, and/or taking certain medications.

What is the health care definition of obesity?

According to the National Heart, Lung, and Blood Institute (in cooperation with the National Institute of Diabetes and Digestive and Kidney Disease), obesity is most often defined in terms of body mass index, or BMI. These numbers are based on a person’s weight and height, with most health care professionals agreeing that there is a strong correlation between BMI and total body fat content. A person who is overweight is usually considered to have a BMI of 25 to 29, while a person who is obese has a BMI of 30 or higher. (For more about BMI, see this chapter.)

What are some reasons for so many people being overweight or obese in the United States?

Although the subject is highly debated, a great deal of research has indicated that there are several major reasons for the overweight and obesity problems in the United States. And the list of reasons is very long and often convoluted as not everyone has the same chemistry, eats the same, or lives under the same conditions. But there are some suggestions for why people have gained so much weight over the past several decades. For example, serving sizes have changed over that time both in homes and in restaurants (in other words, people often eat more now, mainly because food is often plentiful and available). In addition, the average American diet tends to include many foods that are high in fats and sugars. The standard portion size for many foods has increased over the past several years, including “supersized” portions at fast-food restaurants that offer more calories, sugars, and fats. This type of diet, coupled with a lack of physical activity, often leads to people’s becoming overweight and obese. In addition, life has become more stressful for many people. Stress often leads to a change in eating habits (mainly eating more) in response to negative emotions such as sadness, anger, and boredom.

Poor diet and sedentary lifestyle are the two biggest reasons for being obese. America is facing an obesity epidemic, with nearly 36% of Americans falling into this category.

What is fat in the human body?

Fat in the human body is medically called adipose tissue and is found in several places in the body. Fat is made up of unique cells, simply referred to as fat cells. In general, fat cells are found beneath the skin and on top of both kidneys, along with some that is stored in the liver and a small amount in the muscles. In most people, the number of fat cells remains the same after they reach puberty (exceptions are if an adult has liposuction or if the person gains a significant amount of weight). And while the number of fat cells remains the same, each cell can get larger, which is why people “gain weight” without increasing the number of fat cells. (For more about how fats are metabolized-after ingestion-by the digestive tract, see the chapter “How Diabetes Affects the Digestive System.”)

What are white and brown fats?

In general, fat cells are divided into white and brown fats. Overall, a person carries white fat, or fat that cushions the body near the surface and makes up around 90 percent of body fat. These fat cells are large and have little cytoplasm and a small nucleus, with a fat droplet making up around 85 percent of the cell’s volume. They are most important to energy metabolism and heat insulation in the body. Brown fat is mostly found in newborn babies between the shoulders and is important to making heat (called thermogenesis) as newborns do not have much white fat to insulate their bodies and retain heat. The cells have a small amount of fat droplets and many mitochondria, or cell organelles (structures within the cell) that can generate heat. Adults usually have little or no brown fat, but if they do, it is most often found around the upper back, the nape of the neck, the armpits, between the shoulder blades, and deep in the chest cavity.

Is there a connection between white and brown fat, obesity, and diabetes?

According to some studies-and even though most adults carry few or no brown fat cells-some researchers believe that the proportions of white and brown fat cells may be connected to being overweight or obese. They suggest that because brown fat primarily burns calories and white fat stores calories, some overweight and obese people may have less brown fat than adults who are not obese, or the brown fat in a person who is overweight or obese is not as efficient in burning calories. Either way, the fat is more readily stored in these people than burned off.

Exercise may also change a person’s white fat. In a 2016 study, researchers found that exercise may help to control weight and to fend off diabetes by changing white fat into brown. This may be due to a boost in a hormone, irisin, that is produced during exercise. This previously unknown hormone apparently migrates mostly to fat and, through several biochemical processes, causes some of the normally white fat cells to turn to brown fat cells-fat that is known to burn calories and improve control of insulin and blood glucose.

Where does fat collect in the abdomen, especially fat that can lead to obesity?

Two types of fat associated with obesity collect in the upper body (abdomen). The intraabdominal fat-also called visceral or organ fat-collects around organs and represents about 10 percent of the upper-body fat. Around 90 percent is called regular, organ, or abdominal subcutaneous fat and is found under the surface of the skin. It is the type of fat that can be grasped with a hand and is located between the skin and the outer abdominal wall. While fat found under the surface of the skin may be in some ways connected to abdominal obesity and metabolic risk factors, the intra-abdominal fat is thought to be a much stronger indicator-even predictor-of metabolic abnormalities, diseases, and a person’s mortality.

Who discovered the connection between upper-body obesity and the risk of such diseases as diabetes?

In 1947, French physician Jean Vague (1911–2003) was the first person to mention that upper-body obesity was somehow linked to such diseases as gout, atherosclerosis, and diabetes. Later, this finding was further attached to the metabolic syndrome, the clustering of at least three of five conditions, with upper-body obesity being one of the five conditions.

Why is intra-abdominal (visceral or organ) fat thought to affect a person’s health?

Research indicates that fat cells (in particular, intra-abdominal [visceral] fat cells) are considered to be biologically active, with some scientists thinking of the fats as similar to an endocrine organ or gland. This is because the fats can produce hormones and other substances in a person’s body-along with affecting other hormones in the body-that can affect the person’s overall health. The following are some of the connections researchers have made between visceral fat and health:

Cardiovascular disease-Visceral fat pumps out immune-system chemicals called cytokines that can contribute to the increased risk of cardiovascular disease. The cytokines, along with other chemicals in the body, are believed to have a bad effect on cells’ sensitivities to insulin, blood pressure, and blood clotting.

Diabetes-Visceral fat is connected to many of the conditions included in diabetes. For example, it is associated with glucose intolerance and insulin resistance (see next on the list)-which are in turn connected to type 2 diabetes.

Insulin resistance-Research indicates that visceral fat secretes more of retinol-binding protein 4 (referred to as RBP4), a molecule that increases insulin resistance (when the body’s muscle and liver cells don’t respond to the normal levels of insulin and blood glucose levels rise). Thus, if the visceral fat increases, the RBP4 level also increases.

Portal vein connection-Intra-abdominal fats can also be harmful depending on their location in the body. For example, if the excess visceral fat is located near the vein that carries the blood from the intestinal area to the liver, it can cause a problem. (The vein is called the portal vein and has other functions, too.) In particular, intra-abdominal fat can release substances such as free fatty acids that can travel to the liver, where they influence the production of blood lipids. This condition is often associated with higher LDL (the “bad” cholesterol), lower HDL (the “good” cholesterol), and insulin resistance. (For more about cholesterol, see the chapter “How Diabetes Affects the Circulatory System.”)

Women’s health-Other research suggests that for some women, intra-abdominal fat may also be associated with breast cancer and the need for gallbladder surgery.

Dyslipidemia-Dyslipidemia is a condition in which the body has an abnormally high amount of lipids, mainly triglycerides, cholesterol, or both. It is thus connected to intra-abdominal fat.

Inflammation-Research indicates visceral fat is often associated with inflammation in various parts of the body. Thus, because this fat can trigger low-level inflammation, it is usually considered a risk factor for certain chronic conditions associated with inflammation, such as asthma.

Other disease connections-Some research has recently tied several other diseases with visceral fat. One is dementia-one study found people in their early 40s with high levels of visceral fat (compared with those without such fat at that age) were nearly three times more likely to develop dementia, including Alzheimer’s, by their mid-70s to early 80s. Another is colorectal cancer. Some studies indicate that a person with a great deal of visceral fat may have three times the risk of developing colorectal adenomas (or what are usually referred to as polyps) than people with much less intra-abdominal fat; it was also found that these types of polyps in a person’s colon are connected to insulin resistance.

Can intra-abdominal fat be measured?

Yes, there are several ways to measure intra-abdominal (visceral) fat, although some are more accurate than others. The most accurate ways to date are CT scans and full-body MRIs, but not everyone can afford to pay for these methods. Another procedure uses a bioelectrical impedance machine that uses an electric current to differentiate between fat tissues in the abdomen. Still another approach can be done at home, although it is not as accurate as a CT scan or bioelectrical impedance machine. It entails measuring the person’s waist and hip circumference with a tape measure, then dividing the waist by the hip measurement. In most cases, a number greater than 1.0 for men and 0.85 for women is considered excessive amount of visceral fat, whereas a lower number (for example, for a man a result of 36/40, or 0.9) means there is not as much in terms of intraabdominal fat. But this is only an estimate because some of the fat will be subcutaneous fat. To make the number more accurate, measure the waist when you are lying down, then divide by the hip measurement. Since the subcutaneous fat usually will fall to the side of the body when it is lying down, the visceral fat will remain.

Overall, the main reason for understanding a person’s visceral fat measurement is not to “stay within the numbers.” It is merely to let a person know if he or she has a problem with intra-abdominal fat-and then decide what to do if the fat needs to be reduced. This knowledge, in turn, will usually help the person lower his or her risk of such conditions as cardiovascular disease-and diabetes.

What do the terms “apple-shaped” and “pear-shaped” indicate in terms of health?

In terms of health-and abdominal fat-the terms apple-shaped and pear-shaped have certain meanings. Both terms are associated with how a person’s waistline often seems to grow as the person gets older, which also means a possible increase in a variety of health problems. (These terms usually refer to intra-abdominal fat, not the subcutaneous fat.) The big difference is that people who have subcutaneous fat that accumulates in the abdominal area are considered apple-shaped; people who have fat that accumulates in the lower body are considered to be pear-shaped. Thus, apple-shaped people seem to have more health problems associated with their intra-abdominal fat than pear-shaped people, including a higher risk of developing type 2 diabetes.

Apple- (left) or pear-shaped bodies are the result of too much fat being stored in the abdomen or hips, respectively.

Do some races seem to have more intra-abdominal fat than others?

Yes, there appear to be certain connections between a person’s race and intra-abdominal fat. Many studies have shown that Asians have more intra-abdominal fat than Caucasians. And Caucasians have more of the fat than African Americans. But because most of the studies of intra-abdominal fats stress Caucasian populations, it is difficult to determine any more possible racial differences.

What are two of the best and most healthful ways to lose intra-abdominal fat to reduce the risk of developing such diseases as diabetes?

Most research suggests there are two major ways that a person can lose intra-abdominal fat and reduce the risk of developing diseases such as diabetes (especially type 2). These are exercise (individuals who are more physically active have lower amounts of intra-abdominal fat) and reducing calories. Both are considered equally effective in producing moderate weight loss. In addition, although weight loss is the desired outcome of exercise in overweight people, research suggests that even when the person’s body mass does not change, regular exercise can still reduce intra-abdominal fat and shrink the waist size. (For more about exercise and weight loss, see the chapter “Exercise and Diabetes.”)

For example, some studies showed that, if an overweight or obese person exercises around 20 minutes a day for three months, intra-abdominal fat can be reduced by 10 percent. If an overweight or obese person exercises around 60 minutes a day for around that same amount of time, it can translate to a 30 percent reduction in intra-abdominal fat. In addition, the amount of intra-abdominal fat that is lost is, in general, greater than abdominal subcutaneous fat lost.

Can performing sit-ups help get rid of intra-abdominal fat?

For most people, doing sit-ups is good for tightening abdominal muscles. But such spot exercise will not get rid of intra-abdominal (visceral or organ) fat, or what is often referred to in the media as a “beer belly” or “spare tire.” This is because this type of fat lies under the abdominal muscles and within the organs, not just below the surface of the skin as with subcutaneous fat. Thus, doing sit-ups will strengthen abdominal muscles, but unless visceral fat is reduced, the “six-pack abs” won’t be noticed. In fact, it is difficult to do any spot exercise to target fat loss in the body. This is because the body stores fat in a random way, and those locations are usually dictated by the person’s genetics. And, according to some studies, as a person loses weight, the body will most often lose fat in the reverse order in which it was put on.

When it comes to calories, if a person (subject to an individual’s overall health and doctor’s advice) reduces his or her caloric intake by 400 to 700 calories a day, it can mean a 15 to 30 percent reduction in intra-abdominal fat. By focusing on energy intake (calories in), an overweight or obese person can often lower intra-abdominal fat.

Although it is possible to drastically restrict calorie intake, it is often not practical or healthful to do so. Thus, most researchers suggest a more moderate approach to reducing calories. In most overweight or obese people, reducing calories often leads to a reduction in body weight and intra-abdominal fat. The total percentage of loss depends on many factors, but on the average, there is often not only a weight loss but also a reduction in intra-abdominal fat that ranges from 15 to 30 percent.

Do overweight or obese males and females differ in their ability to lose weight and intra-abdominal fat?

Although both males and females can be overweight and obese, there are thought to be some gender differences when it comes to intra-abdominal fat reduction and weight loss. For example, some studies suggest that exercise and/or diet reductions to get rid of intraabdominal fat may not work as well for women as for men. Yet other research indicates that women can significantly reduce intra-abdominal fats though exercise and diet. Thus, many researchers believe that the studies may be confounded by gender differences involving exercise and expended energy, differences in exercise intensity, and duration of the activity. They also cite the fact that women generally have less intra-abdominal fat than men. All of this means that no one truly knows whether males or females have more trouble reducing intra-abdominal fat-and more studies, of course, are needed.

Why doesn’t liposuction work in terms of visceral fat?

Liposuction is the surgical procedure that uses a suction technique to remove fat from various places on the body. Most people who choose to have the procedure wish to enhance and change the contours of their body, including the abdomen, arms, buttocks, calves and ankles, chest and back, hips and thighs, and neck. It is purely cosmetic and is in no way a weight-loss method or treatment for obesity. This is because the fat that is removed is subcutaneous, and the procedure does not reach the inside of the abdominal wall. In other words, liposuction will not get rid of intra-abdominal (visceral) fat.

It is interesting to note that people who have the procedure are permanently getting rid of fat cells-or those cells that they have had all their lives. They cannot be replaced, and if the person does not lead a healthful lifestyle after the operation, there is a risk that the remaining fat cells will grow bigger and he or she will gain weight. This is because when a person gains weight, it’s actually the fat cells increasing in size and volume. Conversely, if the person exercises and eats a healthful diet, the fat cells will decrease in size and volume, and the person will lose weight.

All this may be a moot point if the person has diabetes, too. In most cases, and because of possible complications from the surgery, liposuction is usually not recommended for people who have coronary artery disease, a weak immune system-or diabetes.

What is bariatric surgery?

Bariatric surgery is a somewhat generic term that means most surgeries conducted on people who wish to lose weight. It is not for everyone who wants to lose weight, and in most cases, it is suggested only for extremely obese patients, or obese people who have other severe weight-related health problems, such as type 2 diabetes, heart disease, very high blood pressure, and extreme sleep apnea. It is only used as a “last resort” for most obese cases and only after attempts to lose weight, by eating more healthfully and nutritionally, along with exercise, fail.

In most bariatric surgeries, the person has his or her digestive system altered in such a way as to limit the ability to eat, slow down the absorption of nutrients, or a combination of both. The following lists the most common forms of bariatric surgery performed in the United States at this writing:

Adjustable gastric band (AGB)-In this operation, a small band is placed around the top of the stomach to shrink the opening between the esophagus and stomach and reduce a person’s food intake.

Bilopancreatic diversion with duodenal switch (BPD-DS)-This operation (which is usually only conducted on severely obese patients) involves three procedures: removing much of the stomach, making the person feel fuller after eating; changing the effects of bile and other digestive juices to reduce a person’s digestion and absorption of nutrients; and rerouting food around part of the small intestine in order to lessen the absorption of nutrients.

Roux-en-Y gastric bypass (RYGB)-In this operation, a small part of the stomach is stapled, creating a small pouch. This causes the food to go directly from the pouch to the small intestine, bypassing part of the gastrointestinal tract to limit the amount of food it absorbs.

Vertical sleeve gastrectomy (VSG)-Here, most of the stomach is removed, lessening the amount of food eaten and absorbed by the gastrointestinal tract.

What study linked weight-loss surgery and diabetes remission?

A 2013 study reported in the Annals of Surgery noted possible benefits for some people with type 2 diabetes and weight-loss surgery. The researchers looked at 217 severely obese people with type 2 diabetes, with an average body mass index (BMI; for more about BMI, see this chapter) of 49, an indication of extreme obesity. The participants had weight-loss surgery between 2004 and 2007, and six years later, the researchers found that 24 percent of them were in complete diabetes remission, meaning they had an A1c of less than 6 percent and were not taking any diabetes medication. In addition, 26 percent of the participants were in partial remission, or an A1c of 6 to 6.4 percent and not taking diabetes medication. The researchers also noted that people who had diabetes for less than five years had the most health improvements. Although this is not an endorsement for weight-loss surgery, it may be a possibility for people who have other severe health problems and diabetes. The best way to find out is for the patient to ask his or her health care professional if such surgery is an option.

Three types of bariatric surgery are shown above. (Not pictured is BPD-DS surgery.) Such surgeries should only be considered when all other options for weight loss have proven to be ineffective.

How has recent research explained why bariatric surgery is associated with type 2 diabetes remission?

Researchers have known for many years that patients who have bariatric surgery-or stomach surgeries that concentrate on weight loss-often experience type 2 diabetes remission. In 2016, a Cornell University-led study on mice written up in, appropriately, the journal Gut, suggested why the diabetes goes into remission, even days after the surgery and before the weight is lost. The researchers discovered that TGR5, a bile-acid receptor, along with an increase in bile-acid concentrations known to occur after these surgeries, both help to balance glucose levels in the blood.

This does not mean the researchers advocate bariatric surgery to combat type 2 diabetes, as such surgery is not without risks. Most of these surgeries are conducted on people who have a body mass index (BMI) from 35 to over 40, along with other obesity-related health problems (for more about BMI, see this chapter). But the researchers do want to concentrate on methods other than weight loss to treat diabetes. Thus, they are looking at TGR5 as a possible clue to treatment, especially the link between the TGR5 and bile acid.


What is body mass index, or BMI?

Body mass index is a way of measuring your body’s mass-a statistical measurement that gives an estimate of a healthy body weight based on the height of a person. Overall, it gives you and your doctor a good idea of how you stand weight-wise. In general, for an adult female (males have slightly higher BMI numbers), if you have a BMI of less than 18.5, you are considered underweight; 18.5 to 24.9 means normal weight; 25 to 29.9 means overweight; and over 30 is considered obese. To determine your BMI, take your weight in pounds and your height in total inches. Then multiply your weight times 703, and divide that number by your height squared. For example, if you are 5 feet, 4 inches tall (or 64 inches tall) and weigh 133 pounds, the calculation would be as follows: 133 x 703 = 93,449; 64 inches squared = 4,096; divide 93,449/4,096 = 22.83-your BMI is in the normal range.

What are some of the health risks of having a high BMI?

There are numerous health risks if a person has a high BMI, or body mass index, meaning over 30. Risks include hypertension, dyslipidemia (for more about dyslipidemia and diabetes, see the chapter “How Diabetes Affects the Circulatory System”), type 2 diabetes, cardiovascular disease, stroke, gallbladder disease, osteoarthritis, sleep apnea and respiratory problems, gout, and even certain types of cancer, such as endometrial, breast, and colon cancers.

Is a high BMI the only factor in obesity?

No. Health care professionals also cite genetic, environmental, psychological, and underlying medical problems-all of which may be factors that lead to obesity. Underlying medical conditions may include hypothyroidism, Cushing’s syndrome, depression, and certain neurological problems that can lead to overeating. Drugs, such as steroids, used to treat certain medical conditions may cause weight gain, too. Scientific study has also indicated that obesity may be linked to heredity, but many researchers note that in terms of a “family unit” that shares the same basic diet, it is often difficult to separate genetics from environmental factors.

A simple calculation based on your weight and height will give you your BMI and tell you whether you are at a healthy weight or not.

Why are many doctors concerned about BMI in terms of diabetes?

Health care professionals are usually concerned if a person’s BMI is too high, which often indicates that the individual is very overweight or obese. In addition, many studies have found that a person’s BMI is strongly and independently associated with the risk of being diagnosed with type 2 diabetes.

What is an example of a good BMI for a certain height?

Depending on your height, which is usually considered to be a constant, you can also determine what weight range will send you into another BMI category. For example, here are the weight ranges, the corresponding BMI ranges, and the weight-status categories for a sample height of a man who is 5 feet, 9 inches:

BMI for 5'9" Tall Male

Weight Range


Weight Staus

124 lbs. or less

Below 18.5


125 lbs. to 168 lbs.

18.5 to 24.9


169 lbs. to 202 lbs.

25.0 to 29.9


203 lbs. or more

30 or higher



Do researchers believe that obesity is inherited?

To date, researchers studying obesity genetics have identified more than 30 candidate genes on 12 chromosomes associated with body mass index-or how much weight we carry around (for more about body mass index, see this chapter). For example, in 2007, the first “fat mass and obesity-associated” gene (or FTO) was found on chromosome 16; it’s estimated that people who have this gene variant carry a 20 to 30 percent higher risk of obesity. Another obesity-associated gene is located on chromosome 18. But as many researchers mention, even when the genes are found, they only account for a small part of the gene-related susceptibility to obesity. According to Harvard University’s School of Public Health, recent research shows that genetic factors identified so far in obesity make only a small contribution to a person’s obesity risk-and that our genes are “not our destiny.” In other words, many people who do have the so-called “obesity genes” do not necessarily become obese or even overweight-and often can counteract potential overweight problems owing to genes with exercise and healthful eating habits.

How reliable is BMI as a health indicator?

For several reasons, not everyone thinks that the BMI is a person’s best indicator of health. For example, although the connection between the BMI number and the fatness of a person is fairly strong, the numbers all vary by gender, race, and age; for instance, at the same BMI, older people (on average) tend to have more body fat than younger adults, and highly trained athletes may also have a high BMI, but it is more because of muscles than body fat. Another objection is that the BMI is only one factor related to risk for certain diseases. Thus, some organizations look at other factors to understand a person’s likelihood of developing overweight- or obesity-related diseases. For example, the National Heart, Lung, and Blood Institute guidelines recommend looking at two other factors: A person’s waist circumference (because abdominal fat is often a predictor of risk for obesity-related diseases) and other possible risk factors a person has for diseases associated with obesity (for example, high blood pressure or physical inactivity).

Why are carbohydrates the center of a debate about type 2 diabetes?

Some researchers believe that it is actually carbohydrates in our diets that have made many people overweight and eventually obese, both of which conditions can lead to type 2 diabetes. They believe that insulin resistance in many people is caused by the pancreas’s “wearing out,” as it sends out more and more insulin, so more sugar is stored as fat, which leads to obesity.

The researchers’ solutions seem drastic to some, as they often contradict some commonly “accepted” dietary guidelines. The researchers believe that several foods should be replaced in the diet, as they cause such rapid sugar spikes after eating. These foods include whole grains (which raise the blood sugar drastically after ingestion and can be replaced with such flours as coconut or almond), potatoes, and sugar. This way, the body will not be flooded with sugar followed by insulin and, thus, will lower fat stores in the body. The researchers also believe that a person with type 2 diabetes, or even prediabetes, should eat more protein and fats instead of most carbohydrates. This is because proteins-especially fats-do not cause a spike in blood glucose levels after eating.

Overall, the researchers’ message is that most (especially Western) diets have not cut back on carbohydrates; they also stress that obesity may be linked not to which carbohydrates a person eats but to how much the person eats for his or her particular body. They also note that much of the information about treating diabetes tends to mention the medications as opposed to such alternatives as maintaining a health lifestyle. They do admit, too, that some people do have a genetic predisposition to type 2 diabetes-but their main concern is that along with the increase in type 2 diabetes has come an increase in obesity.

Is type 2 diabetes a problem for low-income people?

Yes, in many cases, type 2 diabetes is a major problem for low-income people, and it can sometimes afflict entire families. A recent study found that at the end of a month, low-income people are admitted to hospitals with low blood sugar more than people with higher incomes. It is thought that this is because without money, the low-income people cannot buy enough to feed their families. This lack of stable access to food can cause a person to have unstable blood glucose levels.


What is the “obesity paradox”?

In the past decade or so, researchers have noticed that there are people who are not obese or overweight but still develop diseases most often associated with excess weight. The phrase “obesity paradox” refers to these normal-weight people who are not obese but still develop diseases such as type 2 diabetes-and those diseases seem to affect them more than they do obese people with diabetes. In one 2016 study from the Journal of the American Medical Association, it was found that normal-weight people who develop type 2 diabetes often have double the risk of dying from heart disease and other causes over people who have type 2 diabetes and are overweight. The paradox comes from the idea that excess weight can “protect” certain people-though the opposite is more often true.

The researchers do not suggest that people become overweight to stave off certain diseases like type 2 diabetes. This is because statistics show that around 85 percent of people who do develop type 2 diabetes are overweight or obese. What they believe is that something other than weight gain is causing the onset and severity of type 2 diabetes in these “normal-weight” people. Some suggest it may be certain conditions not yet researched as much, such as the amount of fat a person carries around his or her waist. Another suggestion is that such conditions for these people may not be the amount of fat itself but how the person stores it in the body. Still another study points to hormones that tell the brain when to eat or when the person has had enough to eat.

What is thought to contribute to diabetes even though it is meant to help?

Food banks have been a good source of foods for people who can’t always afford to pay for groceries. But in 2014, the United States’ largest hunger-relief organization, Feeding America, reported that a third of the 15.5 million households they served reported at least one household member had diabetes. There seem to be several major reasons. For example, if a person (and/or family) has inconsistent access to food, it can worsen a diabetic condition. In addition, many times, inexpensive foods are bought by people trying to stretch their paycheck, with most of those foods being low in fiber and rich in carbohydrates and fats, all of which contribute to obesity and can lead to type 2 diabetes. There are also food banks that cannot afford (or do not offer) many healthful choices. Thus, many people who use those food banks must choose prepackaged or fattening foods that can contribute to obesity-and potentially lead to diabetes.

What study found a possible connection between certain chemicals in the body and obesity?

In a study presented in 2007, researchers found that many obese people in the study actually had higher amounts in their systems of leptin, a hunger-suppressing hormone, but in most cases, the participants’ systems were also resistant to leptin. This hormone is released by fat cells and travels through the bloodstream to the brain. In general, the more fat a person has on his or her body, the more leptin is released. But when a person’s fat level is low-which means the leptin levels are low-it causes the brain to increase the person’s appetite, so he or she eats more and gains weight.

The researchers also discovered that obese people had suppressed ghrelin levels, a chemical the stomach secretes when it is empty to tell the brain that it’s time to eat. Both leptin and ghrelin may contribute to a person’s propensity to eat too much at meals-and they are thus associated with hunger and craving, along with the possibility of contributing to obesity. They may also contribute to the reasons behind the “obesity paradox” (see above), in which the fat, brain, and leptin do not respond correctly-and many times lead to type 2 diabetes without the person’s being obese.

How many Americans are thought to be obese?

Currently, it is thought that overweight (meaning a body mass index, or BMI, of 25 to 30) and obese (meaning a BMI of over 30) Americans represent about 65.2 percent of the population. Although it is a worldwide problem, in the United States alone, it is estimated that one in four people are obese. Still another statistic states that more than half of the adults in the United States are overweight.

What does air pollution have to do with obesity-and perhaps diabetes?

Although more research needs to be done, in yet another study on obesity, researchers working jointly from Duke and Peking Universities suggested that air pollution may play a part in diet-associated weight gain, inflammation in the body (thought to be a contributing factor to obesity), and insulin resistance. They base their suggestions on studies conducted on rats, in which the animals were exposed to the polluted city air of Beijing or air cleaned by an air filter that removed most of the pollutants. The scientists found that after 19 days, the animals in the polluted air showed signs of inflammation and had a 50 percent higher level of LDL (low-density lipoprotein, considered “bad”) cholesterol, 46 percent higher triglycerides, and 97 percent higher total cholesterol, all thought to be contributors to obesity. In terms of diabetes, the rats also had an increase in insulin resistance. The animals’ offspring did no better and were heavier than the offspring in the filtered air, even with eating the same diets. If this study can be translated to humans, it may show how major air pollution can contribute to the growing numbers of people who are not only obese but who also develop diabetes.

How many people who develop type 2 diabetes are obese or overweight?

According to Harvard Medical School, it is estimated that around 85 percent of people who develop type 2 diabetes are overweight or obese. Although this estimate applies to the U.S. population, it is no doubt close to the percentage of people worldwide who develop type 2 diabetes.

What are the three major conditions associated with obesity?

According to some statistics, one in three Americans and one in four adults worldwide have at least three conditions that often accompany obesity. These three major conditions include type 2 diabetes, high cholesterol, and high blood pressure. These disorders, usually found in combination, double a person’s risk of heart attack and strokes. Another condition called fatty liver-when a large amount of fat accumulates in the liver-is also caused by obesity and can lead to liver failure.