A recent scientific review published in JAMA adds to evidence that obesity is linked to a higher risk of several types of cancer. The researchers also highlight steps that may help reduce that risk over time.

For people living with obesity, this research may help explain how body weight can affect cancer risk and what may help lower that risk.

Obesity and Cancer: What the Research Shows

The review found that overweight and obesity are associated with about 10 percent of new cancer diagnoses each year in the United States.

Researchers identified several types of cancer that are linked to higher body weight. These include:

• Colorectal cancer
• Endometrial cancer
• Postmenopausal breast cancer
• Kidney cancer
• Liver cancer
• Pancreatic cancer
• Ovarian cancer
• Thyroid cancer
• Gallbladder cancer

Some of these cancers, such as endometrial cancer, may be especially strongly linked to obesity. In some cases, excess body weight is associated with up to 50 percent of cancer diagnoses.

Inflammation and Hormones

Fat tissue does more than store energy. It also makes hormones and other signals that affect the body. Excess fat can lead to:

• Ongoing inflammation
• Higher levels of certain hormones, including estrogen
• Changes in proteins that control hunger and metabolism

These changes may encourage cancer cells to grow, especially in cancers affected by hormones, such as breast or endometrial cancer.

Effects on the Immune System

Obesity may also make it harder for the immune system to find and destroy abnormal cells. When abnormal cells are not destroyed, cancer cells may have more chances to grow and spread.

Energy for Tumor Growth

Cancer cells need energy to grow. The review suggests that excess fat tissue may give cancer cells fuel to survive and keep growing.

Can You Reduce Your Cancer Risk?

The study also looked at ways people may be able to lower their risk of obesity-related cancer.

Weight Loss of 10 Percent or More

The review included observational studies, which follow real people’s health choices and outcomes. In these studies, people who lost more than 10 percent of their body weight through bariatric surgery (weight loss surgery) or medications had small but meaningful drops in cancer risk.

Other research included in the review suggests that even more modest weight loss may be linked to lower risk for certain cancers, although results are mixed.

Lifestyle Changes

Healthy habits may help lower inflammation in the body. These include:

• Eating a balanced, nutrient-rich diet
• Getting regular physical activity
• Taking breaks from long periods of sitting

More research is needed to understand the full impact of these changes on cancer risk.

Medications and Surgery

Some treatments used for weight management may also play a role, including:

• Glucagon-like peptide 1 (GLP-1) receptor agonists, a class of medications used for diabetes and weight loss
• Bariatric surgery

Medications and surgery have been linked to lower rates of some obesity-related cancers in observational studies. However, they don’t work the same way for everyone, and more research is needed to understand how they may affect cancer risk over time.

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