Endometrial Cancer and Obesity

Written by Keri Wiginton
Medically Reviewed by Traci C. Johnson, MD on April 06, 2025
7 min read

Endometrial cancer is one of the few cancers that doesn’t stay quiet. That’s why you should never brush off spotting between periods or any bleeding after menopause. When caught early, this cancer is usually curable. 

Knowing the signs is important – but so is understanding what raises your odds. Some risk factors for endometrial cancer, like your genes, are out of your control. But one of the biggest drivers is something you can take steps to change: excess body fat. 

“Obesity is a medical condition that raises the risk for many health problems, including endometrial cancer,” says Rebecca Stone, MD, a gynecologic oncologist with Johns Hopkins Medicine. “But the good news is, there are tools and treatments that can help.”

Most people with a larger body won’t get endometrial cancer. But excess fat can disrupt hormones and other systems, especially if you also have related health issues like:

  • Polycystic ovary syndrome (PCOS)
  • Type 2 diabetes
  • High insulin levels (hyperinsulinemia)
  • Insulin resistance 

How common is endometrial cancer in people with bigger bodies?

Let’s start with how doctors define size. Overweight and obesity are medical terms based on body mass index, or BMI. It’s not a perfect tool, but it gives a rough idea of how much body fat you have based on your height and weight. 

A BMI of 25 or more falls into the overweight range. A BMI of 30 or more is considered obesity. 

About 6 out of 10 endometrial cancer cases in the U.S. are linked to overweight or obesity. And the higher your BMI, the greater your risk. For every five-point jump, your odds go up by about 50%. 

“If you have a BMI of 30 or higher, that basically doubles the risk of endometrial cancer, to 6% to 7%,” Stone says. “And if you have a BMI of 40 or higher, the risk may even be as high as 9% to 10%.” 

Rates of endometrial cancer are going up – especially among younger adults with obesity and certain marginalized racial and ethnic groups. But body size is likely only part of the story. 

“We don’t think obesity alone explains the rise in endometrial cancer in Hispanic and Black people,” Stone says. “It’s probably a mix of factors – less access to timely care, more aggressive cancer types, and environmental influences that we’re still learning about.”

Most obesity-linked endometrial cancers grow slowly. But recent research shows that high levels of body fat may also play a role in more aggressive kinds, like serous, clear cell, and carcinosarcoma. 

Estrogen and progesterone work together to control your menstrual cycle. Each month, estrogen tells the lining of your uterus (endometrium) to grow. Progesterone helps it break down and shed during your period.  

Your body needs to clear out that tissue regularly. But if estrogen stays too high and progesterone stays too low, the lining may build up. Over time, those cells may start to change in ways that lead to cancer. 

What does body size have to do with it? 

The more fat tissue you have, the more estrogen ends up in your bloodstream. That’s because fat can turn other hormones (like androgens) into estrogen. High levels of this hormone can cause the uterine lining to grow too much, which can lead to a condition called endometrial hyperplasia.

“Hyperplasia is when cells grow too much and make pre-cancer,” Stone says. “And then that pre-cancer can develop into cancer in upwards of 40% of cases.” 

This hormone imbalance is one of the main reasons obesity raises the risk of endometrial cancer – especially after menopause, when progesterone levels fall naturally. 

Other things that boost your lifetime exposure to estrogen include: 

  • Irregular ovulation or missed periods
  • Starting your period at an early age
  • Going through menopause late 
  • Never being pregnant

Insulin is a hormone that helps move sugar from your blood into your cells, where it’s used for energy. But sometimes, the body stops responding to insulin the way it should. That’s called insulin resistance. 

When that happens, your pancreas makes more insulin to keep your blood sugar stable. This leads to high insulin levels in the blood, or hyperinsulinemia. 

People with obesity, type 2 diabetes, or PCOS often have high levels of insulin and another hormone called insulin-like growth factor 1 (IGF1). These hormones tell cells to grow and stick around too long, which can lead to cancer.

High blood sugar adds to the problem by feeding these fast-growing cells, which also raises the risk of abnormal cell growth and cancer. 

Extra weight, especially around your belly (called visceral fat), can trigger inflammation that doesn’t go away. Over time, that can:

  • Tell cells to grow and divide too much
  • Damage your DNA
  • Block old or damaged cells from dying off

Inflammation can also affect tumor suppressor genes, which are supposed to stop cancer from forming. When those protective genes get hurt, cancer cells can grow more easily. 

All of that raises your chances of cancer in the uterus and elsewhere in the body. 

Fat cells do more than make extra estrogen. They also change how other hormones and proteins work.

Obesity can:

  • Lower SHBG (sex hormone-binding globulin), a protein that helps balance estrogen 
  • Raise leptin, a hormone that controls appetite and metabolism
  • Lower adiponectin, a hormone that reduces inflammation and helps regulate estrogen

Leptin controls hunger, but people with obesity may stop responding to it and make too much. That can fuel inflammation. When adiponectin levels fall, your body has a harder time protecting itself against cancer-causing changes. 

Polycystic ovary syndrome (PCOS) is a hormone condition that can affect people of any size, but it’s common in those with obesity. If you have it, you may not ovulate regularly. That can lead to long or irregular menstrual cycles where the uterine lining builds up. 

“That’s why PCOS is related to pre-cancers and cancers of the uterus, because you’re not shedding that endometrium every month,” Stone says. 

You can’t always prevent endometrial cancer. But there are steps you can take to lower your odds, especially if you are overweight or have obesity.  Here’s what you can do: 

Lose a little weight. 

A drop of 5% to 10% may lower inflammation, balance hormones, and improve insulin sensitivity. If you have trouble lowering body fat through diet and exercise alone, ask your doctor about weight loss medications or surgery. 

Move your body. 

People who get a lot of physical activity are less likely to get endometrial cancer, compared to those who don't move as much. Aim for at least 30 minutes of aerobic exercise most days with a couple of days of strength training each week. 

Exercise lowers estrogen, reduces inflammation, and improves your overall health and well-being – even if your weight stays the same. 

Discuss hormone therapy. 

Ask if progestin-based hormonal therapies might be right for you, especially if you have PCOS or a condition that thickens the lining of your uterus. If you’ve gone through menopause, learn about your endometrial cancer risk before you start estrogen-only replacement therapy. If you still have a uterus, you should never be on estrogen-only replacement therapy, as it can lead to uterine cancer. If you have a uterus and are on hormone replacement therapy, you should be on a progesterone along with the estrogen.

Know your genetic risks.

If you have Lynch syndrome or hereditary nonpolyposis colon cancer (HNPCC), your lifetime risk of endometrial cancer is much higher. Your doctor may talk with you about preventive options, including surgery to remove your uterus and ovaries. 
 

Obesity raises your odds of endometrial cancer through excess estrogen, high insulin levels, and chronic inflammation. Weight loss, regular exercise, and managing conditions like PCOS, diabetes, insulin resistance, and hyperplasia can help reduce your risk. 

If you’ve had heavy or irregular bleeding for more than a few months – or if you’ve gone through menopause and have any bleeding – see your doctor. Most of the time, it’s not cancer, but it’s always worth checking. 
 

What is the strongest risk factor for endometrial cancer?

Obesity is the biggest risk factor you can change. People with genetic conditions like Lynch syndrome or hereditary nonpolyposis colon cancer (HNPCC) also have a higher chance.   

What should I avoid if I have endometrial cancer? 

Skip high-calorie foods that can lead to more weight gain. You’ll also want to avoid estrogen-only hormonal treatment, unless your doctor says otherwise. It’s also best to limit alcohol and not smoke. 

What kind of cancer is most strongly linked to obesity?

Endometrial cancer is high on the list, but postmenopausal breast cancer ranks even higher. In men, or people assigned male at birth, colon cancer is the most common obesity-related cancer.