Many factors cause people to become overweight or obese, including genetic, hormonal, environmental, emotional, and cultural factors. People who are overweight or obese have a higher risk of many serious health conditions, including type-2 diabetes, high blood pressure, and heart disease. Being overweight or obese is also associated with an increased risk of cancer.
Weight gain and cancer risk
Several studies have explored why being overweight or obese may increase cancer risk and growth. The possible reasons that obesity is linked with cancer include:
- Increased levels of insulin and insulin growth factor-1 (IGF-1), which may help some cancers develop
- Chronic, low-level inflammation, which is more common in people who are obese and is linked with an increased cancer risk
- Higher amounts of estrogen produced by fat tissue, which can drive the development of some cancers, such as breast and endometrial cancers
- Fat cells may also affect processes that regulate cancer cell growth.
How your weight changes throughout your life may also affect your risk for cancer. Studies have shown that the following factors can affect your cancer risk:
- High birth weight
- Gaining weight as an adult
- Losing and regaining weight repeatedly
Being overweight or obese is clearly linked with an increased risk of many types of cancer, including cancers of the:
- Breast (in women past menopause)
- Colon and rectum
- Endometrium (lining of the uterus)
Being overweight or obese might also raise the risk of other cancers, such as:
- Non-Hodgkin lymphoma
- Multiple myeloma
- Aggressive forms of prostate cancer
In addition, having too much belly fat , regardless of body weight, is linked with an increased risk of colon and rectal cancer, and is probably linked to a higher risk of cancers of the pancreas, endometrium, and breast cancer in women past menopause.
But the links between body weight and cancer are complex and are not yet fully understood. while studies have found that excess weight is linked with an increased risk of breast cancer in women after menopause, it does not seem to increase the risk of breast cancer before menopause. The reasons for this are not clear.
The timing of weight gain might also affect cancer risk. Being overweight during childhood and young adulthood might be more of a risk factor than gaining weight later in life for some cancers. For example, some research suggests that women who are overweight as teenagers (but not those who gain weight as adults) may be at higher risk for developing ovarian cancer before menopause.
How might body weight affect cancer risk?
- Excess body weight may affect cancer risk through a number of mechanisms, some of which might be specific to certain cancer types. Excess body fat might affect:
- Immune system function and inflammation
- Levels of certain hormones, such as insulin and estrogen
- Factors that regulate cell growth, such as insulin-like growth factor-1
- Proteins that influence how the body uses certain hormones, such as sex hormone-binding globulin
Does losing weight reduce cancer risk?
weight loss might reduce the risk of breast cancer (after menopause), more aggressive forms of prostate cancer, and possibly other cancers, too.
Somebody changes that occur as a result of weight loss suggest it may, indeed, reduce cancer risk. overweight or obese people who intentionally lose weight have reduced levels of certain hormones that are related to cancer risk, such as insulin, estrogens, and androgens.
Measuring weight gain
Obesity is often measured with body mass index (BMI): the ratio of a person’s weight and height and waist measurements. A normal BMI is between 18.5 and 24.9. A BMI between 25 and 29.5 is considered overweight, while a BMI of 30 or higher is obese. In addition, people with larger waist measurements have a higher risk of various diseases, such as heart disease. A normal waist measurement is under 40 inches for men and under 35 inches for women.
Weight management tips
To control weight gain, be aware of what you eat and how much you exercise. Here are some tips to help:
- Eat more vegetables, fruits, lean protein, and whole grains. Some types of food, such as broth-based soups, also help a person feel “full” faster.
- Limit foods and beverages that are high in sugar, such as juice and soda.
- Eat and drink only as many calories as you need to maintain a healthy weight and support your level of physical activity.
- Aim for 30 to 60 minutes per day of moderate to intense physical activity on most days. But even a small increase in physical activity has benefits.
Suggestions for people who are overweight or obese
If you are currently overweight or obese, it is best to start by taking steps to lose weight through nutrition and exercise. Aim to lose 5% to 10% of your body weight as your first goal. Although this amount may seem small, research shows that even losing 5% to 10% of your weight is beneficial. Most hospitals and health care organizations have professionals—such as dietitians—on staff who can provide weight management counseling and treatment.
Sometimes nutritional changes and increasing physical activity aren’t enough. But there are other steps you can take. The National Institutes of Health approach to obesity treatment includes:
A change in lifestyle behaviors. First, change behaviors to reduce the amount of food eaten and increase physical activity before considering other weight loss treatments. A registered dietitian, exercise physiologist, clinical psychologist, or doctor who specializes in weight loss can help.
Behavior change support. For many, being overweight or obese is more complex than simply eating too much and exercising too little. It’s important to get support when you are trying to lose weight. Most weight loss programs include sessions with a dietitian or weight loss specialist to help you make healthy lifestyle changes and stick with them over time.
Weight loss surgery, or bariatric surgery, is a term for a variety of procedures that make a person’s stomach smaller. This may be an option for people with a BMI of 40 or higher. Or, for those with a BMI of 35 or higher who have another serious health condition related to obesity.
people who are overweight or obese should be encouraged and supported if they try to lose weight. Aside from possibly reducing cancer risk, losing weight can have many other health benefits, such as lowering the risk of heart disease and diabetes. Losing even a small amount of weight has health benefits and is a good place to start.