Tag Archives: obesity

Can Belly Fat Cause Cancer?

Diet, Habits, & Other Behaviors, Prevention, , , , , ,

Ammu Dinesh and Claire Viscione, National Center for Health Research

Belly fat is common among men and women. However, when a person’s body shape looks more like an apple than a pear, that could increase their likelihood of developing cancer. 

More than two-thirds of adult Americans are overweight or obese.1 Most people know that obesity increases the risk of diabetes, heart disease, and high blood pressure. But did you know that being overweight increases your chances of developing cancer, and that having an “apple” body shape due to belly fat can increase your chances of developing cancer even if you are not overweight?

Why is belly fat dangerous?

Whether your body fat is located at your waist (giving you an apple shape) or hips (giving you a pear shape) makes a difference to your health. Women tend to gain more belly fat as they get older. Regardless of their weight, white, black, and Latina women with a waistline measurement of 35 inches or more have higher health risks. This is also true for Asian women with a waistline of 31 inches or more. Although it is important to get rid of excess fat in general, belly fat is the most threatening to your health.

Physicians use often use body mass index (BMI) to estimate whether you are overweight or obese. However, determining your waist circumference is just as important. Even if you are not overweight or obese, if you have a lot of belly fat, you are more likely to develop cancer.

Unlike the fat that sits just beneath the skin, the fat that sits around internal organs is called visceral fat.2 This fat is the most dangerous, and it is typically what shows up as belly fat. If you measure your waistline, you can get a good idea of whether you have a dangerous amount of belly fat. 

Women Men
Low health risk 31.5 inches or less 37 inches or less
Intermediate health risk 31.6 – 34.9 inches 37.1 – 39.9 inches
High health risk 35 inches or more 40 inches or more

Table 1. What does your waistline measurement mean? 2

Several studies have looked at the relationship between belly fat and cancer. One study followed over 150,000 post-menopausal women ages 50-79 for about 20 years.3 This study found that women who have extra belly fat are at higher risk of death regardless of their weight. Causes of death in the study included cardiovascular disease and cancer. The women of normal weight who had extra belly fat tended to be older, nonwhite, and with less education and income. They were also less likely to use menopausal hormones and to exercise. 

To figure out your BMI for the chart below, enter your height and weight into this calculator.

Apple Shape (Extra Belly Fat) Not “Apple Shape”
Not Overweight (BMI below 25) 20% more likely to die from cancer within 20 years —
Overweight (BMI of 25-29.9) 19% more likely to die from cancer within 20 years 4% less likely to die from cancer within 20 years
Obese (BMI of 30 or higher) 26% more likely to die from cancer within 20 years 4% less likely to die from cancer within 20 years

Table 2. Likelihood of death due to cancer in women based on BMI.3

Women who were not overweight or obese but had extra belly fat were just as likely to die from cancer as overweight women with extra belly fat.

A different study followed over 3,000 men and women for 7 years.4 They used CT scans and physical exams to look at the fat throughout the body. Over the course of the study, the men and women developed 141 cases of cancer, 90 heart-related incidents, and 71 deaths from various causes. The study found that people with more belly fat, specifically visceral fat, were about 44% more likely to develop cancer and heart disease, even when adjusting for waist circumference. 

What can you do?

As you can see, belly fat can be very dangerous, especially for women, even if they are not overweight. Losing weight or preventing weight gain can lower health risks. By exercising regularly, you can get rid of unhealthy belly fat. It is also important to change your diet to eat foods that are high in nutrients and essential vitamins. You can do this by eating more fresh vegetables, nuts, and whole-grain breads instead of processed meat, red meat, candy, pasta, and white bread. These few changes can help you lose belly fat and improve the quality and length of your life.

Local bans on unhealthy food and drinks may also be effective in reducing belly fat. A 2019 study shows that a ban on the sale of sugar-sweetened beverages at a large college campus substantially decreased consumption and led to significantly less belly fat.5 Students who stopped drinking the beverages had improved insulin resistance and lower cholesterol. The combination of the ban and a brief motivational talk was even more effective than the ban by itself.

Learn more about how extra body fat can increase your risk for developing cancer, and how you can make a commitment to your health and reduce risky belly fat:

 

All articles on our website have been approved by Dr. Diana Zuckerman and other senior staff.

 

References:

  1. Center for Disease Control and Prevention. FastStats- Overweight Prevalence. CDC.gov. https://www.cdc.gov/nchs/fastats/obesity-overweight.htm. Updated June 13, 2016.
  2. Harvard Health Publishing. Abdominal obesity and your health. Health.Harvard.edu. https://www.health.harvard.edu/staying-healthy/abdominal-obesity-and-your-health. September 2005. Updated January 20, 2017.
  3. Sun Y, Liu B, Snetselaar LG, Wallace RB, Caan BJ, Rohan TE, et al. Association of Normal-Weight Central Obesity With All-Cause and Cause-Specific Mortality Among Postmenopausal Women. JAMA Network Open. 2019;2(7):e197337. https://www.ncbi.nlm.nih.gov/pubmed/31339542.
  4. Britton KA, Massaro JM, Murabito JM, Kreger BE, Hoffmann U, Fox CS. Body Fat Distribution, Incident Cardiovascular Disease, Cancer, and All-Cause Mortality. Journal of the American College of Cardiology. 2013; 62(10): 921-925. http://www.onlinejacc.org/content/62/10/921.
  5. Epel ES, Hartman A, Jacobs LM, Leung C, Cohn MA, Jensen L, et al. Association of a Workplace Sales Ban on Sugar-Sweetened Beverages With Employee Consumption of Sugar-Sweetened Beverages and Health. JAMA Network Open. 2019. doi:https://doi.org/10.1001/jamainternmed.2019.4434

Weight and cancer: What you need to know

Diet, Habits, & Other Behaviors
Brandel France de Bravo, MPH, Noy Birger, Shahmir Ali ABD, and Ealena Callender, MD, MPH,  Cancer Prevention and Treatment Fund

There are many reasons why being overweight is bad for our health, but most people
don’t realize that cancer is one of them.  Of course, excess body weight can contribute
to serious medical conditions such as heart disease and type II diabetes. Still, more
recent research shows that excess body fat also increases the risk of developing certain
types of cancer.

Researchers estimate that more than 481,000 of newly-diagnosed cancer cases
worldwide in 2012 were due to overweight or obesity. [1] An estimated 111,000 cancer
cases in North America are caused by being overweight or obese. This represents 23%
of total global cancer cases – the highest of any region. In addition, three cancers
accounted for 73% of all obesity-related cancers among women globally: endometrial
cancer, postmenopausal breast cancer, and colon cancer. For men, kidney and colon
cancers accounted for 66% of all obesity-related cancers. Other cancers associated
with overweight and obesity include prostate cancer, several gastrointestinal cancers,
and non-Hodgkin’s lymphoma.

In 2018, American Cancer Society researchers concluded that each year from 2011 to
2015, approximately 37,700 cancer cases in men in the U.S. and 74,700 cancer cases
in women aged 30 years or older were attributable to excess body weight. [2] Among men,
the excess cancers ranged from 3.9% in Montana to 6.0% in Texas. In women, the
excess risk of cancer was almost twice as high as for men, ranging from 7.1% in Hawaii
to 11.4% in Washington, DC. The highest number of weight-related cancers were
primarily found in southern and midwestern states, as well as Alaska and Washington,
D.C. Overall, cancers attributable to excess body weight account for at least 1 in 17 of
all cancers in each state.

The good news is that a large 2014 study showed that with a healthy diet and regular
exercise, postmenopausal women may significantly reduce their cancer risk. [3]  In the
study, researchers defined a healthy diet as one that limits red meat and processed
meat, emphasizes whole grains over refined grains, and includes two and a half cups of
vegetables and fruits daily. In addition, regular exercise involves at least 150 minutes of
moderate-intensity physical activity or 75 minutes of vigorous-intensity physical activity
every week. Those with the healthiest diets and most active lifestyles saw their chance
of getting breast cancer drop by 22%, their likelihood of colon cancer drop by 52%, and
their overall chance of dying during the 12-year study drop by 27%. While all the women
who ate better and exercised more lowered their chances of developing cancer, non-
white women seemed to benefit the most.

A 2020 study of more than 8,000 Black and White men and women also found that
exercise helps lower the likelihood of dying from cancer. The study found that inactive
people (whether couch potatoes or sitting at a desk all day) were more likely to die from
cancer. At the same time, those who engaged in light to moderate physical activity were
less likely to die from cancer. [4]

In 2022, a study of adults aged 59 to 82 found that those who were as physically active
as was recommended by the Physical Activity Guidelines for Americans were less likely
to die of cancer than those who were less active. [5] All men and women in the study
who were at least moderately active were less likely to die from cancer or
cardiovascular disease than those who were not active at all. In addition, when
researchers evaluated the type and intensity of activity, the activity that seemed most
likely to reduce the chance of dying from cancer was running, followed by other aerobic
exercise, swimming, and cycling.

How does obesity increase the risk of developing cancer?

Excess body weight results in extra body fat – which has unique features that can make
it more likely for an obese person to get cancer. [6] Body fat, also known as adipose
tissue, contains an abundance of cells that cause chronic inflammation and make it
easier for tumors to grow.

Chronic inflammation in individuals with excess body fat may also contribute to insulin
resistance. [7]  Insulin is a hormone that helps our cells use glucose – a type of sugar
found in the foods we eat – to make energy. Insulin resistance means our bodies can’t
respond properly to insulin, and the glucose we need for energy stays in our blood,
where it can’t be used. Too much glucose in our blood – also referred to as high blood
sugar levels or hyperglycemia – increases the likelihood of getting and dying from
cancer. [8] Elevated blood sugar levels lead to an increase in insulin and similar hormones
that cause tumors to grow. The higher the insulin level of a breast cancer patient, the
greater the chance of death. [9] For example, one study of non-diabetic women with early-
stage breast cancer found that women with the highest fasting insulin levels had three
times the risk of recurrence and death compared with women with the lowest insulin
levels. High insulin levels may also interfere with the way certain cancer drugs work,
making treatments less effective. [10]

Researchers think the danger of excess weight is partly due to hormones secreted by
fat tissues, such as estrogen. In women, estrogen comes from a different source before
and after menopause. Before menopause, a woman’s ovaries secrete estrogen. After
menopause, estrogen comes from other tissues in the body. For obese postmenopausal
women, most estrogen comes from body fat, which can encourage the growth of cancer
cells. [11,12] Increased estrogen and increased body fat increase the likelihood of
developing postmenopausal breast cancer and endometrial cancer (also called cancer
of the uterus) in women. [11,12]

The location of body fat also may be important. Fat tissue deep inside your body
wrapped around your organs may increase the risk of developing cancer. For example,
one study followed 3,086 men and women for up to seven years and used medical
imaging scans and physical exams to assess the location of excess fat deposits. [13] After
statistically controlling for the effects of age, exercise habits, BMI, and eating habits,
researchers concluded that those with more fat deep inside the body, compared to
those with fat mostly just beneath the skin, were more likely to develop heart disease
and cancer.

How new is this news?

Researchers have documented the link between obesity and cancer
for many years. In 2003, based on a study of more than 900,000 adults, researchers
estimated that 90,000 cancer deaths could be avoided if adults maintained a normal
body weight. [14] Of all deaths from cancer in Americans over age 50, as many as 14% in
men and 20% in women may be attributable to overweight and obesity. [15]

Every additional study helps to explain how it is that fat fuels tumor growth. Renehan et
al.’s 2012 study, which seemed to be groundbreaking at the time, is based in part on an
earlier meta-analysis (a type of statistical analysis that combines many studies) in which
many of the same authors analyzed more than 200 comparable data gathered from
different countries around the world. [16] The meta-analysis found that excess weight in
men was most strongly associated with cancer of the esophagus, thyroid, colon, and
kidneys. According to the meta-analysis, being overweight did not appear to increase a
man’s risk of prostate cancer. On the other hand, one U.S. study found that an
overweight man with prostate cancer is more likely to die of it than a man with prostate
cancer who is not overweight. [17]

According to the meta-analysis, excess weight in women increases the chances of
developing endometrial cancer, cancer of the gallbladder, esophagus, and kidneys. A
few other cancers were also associated with being overweight for both men and
women, including leukemia, multiple myeloma, and non-Hodgkin’s lymphoma, but the
link was weaker. In men, rectal cancer and malignant melanoma also seemed related to
weight. In women, those with a higher BMI were slightly more likely to be diagnosed
with post-menopausal breast cancer, cancers of the pancreas and thyroid, and colon
cancer.

Additional studies have come to similar conclusions. For example, the American
Institute for Cancer Research (AICR) estimated that excess body fat is responsible for
49% of endometrial cancers; 35% of esophageal cancers; 28% of pancreatic cancers;
24% of kidney cancers; 21% of gallbladder cancers; 17% of breast cancers; and 9% of
colon cancers. [18]  In addition, AICR estimates that over 100,000 new cases of cancer
each year are due to excess body fat, which is similar to estimates from the 2018
American Cancer Society study.

Neuhouser’s study, conducted at 40 U.S. clinical centers, of women ages 50 to 79
followed for about 13 years, showed that women who gained more than 5% of their
baseline weight during the study’s follow-up period had a modest increase in their
chance of getting breast cancer. [19] The risk was most significant for women with a body
mass index (BMI) over 35 — they were 60% more likely to develop breast cancer than
women of normal weight. Keep in mind that a BMI of 30 or higher is considered obese.

A 2016 study found that the link between obesity and cancer is more robust in some
countries than others. [20] Middle Eastern countries have the highest proportion of
overweight and obesity in the world and a high proportion of obesity-related cancer. [20] In contrast, countries in sub-Saharan Africa and Asia have only seen a limited increase in
BMI over the last 30 years. Likewise, North America and Europe have a large proportion
of obesity-related cancers, while countries in sub-Saharan Africa and Asia have a
smaller proportion of obesity-related cancer.

Several studies show that high dietary fat intake increases the risk of post-menopausal
breast cancer, [21]  prostate cancer, [22]  and pancreatic cancer. [23] Researchers have also
found that high-fat diets may increase the likelihood of death from cancer, while low-fat
diets reduce the chances of cancer recurrence. [24] It is unclear whether weight or diet is a
stronger predictor of increased cancer risk, although red meat and processed meat
have been found to increase the risk of some cancers. For more information, see our
articles entitled “Red Meat: The News is Not Good” and “Are Processed Meats More
Dangerous Than Other Red Meats?”

Does losing weight reduce your risk of cancer?

Can losing weight help prevent you from getting cancer? The evidence is clear for some
cancers but not for others. For example, postmenopausal women who lose weight may
reduce their chance of getting breast cancer. [25] Also, weight loss may reduce the
likelihood of gastroesophageal reflux – which may be linked to esophageal cancer. In
addition, some studies have found an association between weight loss and decreased
chance of getting prostate cancer.

Men and women who experience significant weight loss after bariatric surgery may
decrease their likelihood of getting cancer. Bariatric surgery, also called weight-loss
surgery, is generally associated with a decrease in body weight of 20% to 35%. [26] A
2022 study of 30,318 men and women compared the incidence of cancer and cancer-
related death between obese patients who had bariatric surgery and those who did not.
The incidence of most types of cancer and cancer-related death was lower in the
surgical weight loss group. This difference was most significant for endometrial cancer –
the cancer most strongly associated with obesity.

Other studies of obese patients who intentionally lost weight found a decrease in certain
factors in the blood that encourage tumor growth. Called tumor growth factors, these
markers represent chronic inflammation and create a setting that makes it easier for cancer cells to grow. [27,28]  Estrogen – a hormone associated with postmenopausal breast cancer and endometrial cancer – also decreased in women who intentionally lost weight. [27] The study found that women who experienced just a 10% weight loss saw their blood estrogen levels decrease by at least 33%. Overall, researchers have not reached a conclusion about the association between weight loss and postmenopausal breast cancer. Although one study showed a decreased likelihood when the weight loss occurs after age 30 but before menopause, [28] other studies have found no impact at all. [29]

What we know and don’t know

Decreasing the likelihood of getting cancer is one of the many benefits of achieving and
maintaining a healthy body weight. However, we still do not fully understand how a
person’s weight, diet, level of physical activity, and genes all work together to determine
one’s cancer risk.

Bottom Line

After giving up tobacco, watching your weight and staying active are your best forms of
health insurance. For guidelines and tips on living a healthy lifestyle, read Eating Habits
That Improve Health and Help with Weight Loss and BMI. [30]

All articles are reviewed and approved by Dr. Diana Zuckerman and other senior staff.

The National Center for Health Research is a nonprofit, nonpartisan research, education and advocacy organization that analyzes and explains the latest medical research and speaks out on policies and programs. We do not accept funding from pharmaceutical companies or medical device manufacturers. Find out how you can support us here.

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