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Breast Cancer Prevention: What Is Considered a Healthy Weight?

By BCRF | January 8, 2018

In Part One of our prevention series, we explain the science behind maintaining a healthy weight.

The Body Mass Index

Simply put, a healthy weight is defined by the body mass index (BMI). This is the ratio of one’s body mass (density) to one’s height, given by the formula: weight (kg)/ height (m2).  The ranges of BMI and how it is interpreted are as follows:

A BMI of:

  • Less than 18.5 is considered underweight
  • Between 18.5–25 is considered to normal or healthy weight for a given height
  • Between 25–30 is considered overweight
  • Greater than 30 is considered extremely or morbidly obese (30 pounds or more overweight)

BMI is considered a surrogate marker or biomarker. It is not a direct measurement of body fat, but has been shown clinically to correlate with risk of obesity-related diseases, such as cardiovascular disease and Type II diabetes. The measurement has its limitations. For instance, a very fit athlete could have a high BMI and appear to be at high risk of heart disease of diabetes if his/her BMI was the only measurement used to calculate risk of disease.

More information about BMI and to calculate your own BMI can be found on the Centers of Disease Control website.

When should you know your BMI?

It is never too early to strive to meet the guidelines for a healthy weight. Habits we learn when young and are reinforced tend to become part of our lifestyles. Therefore, it is important that kids exercise and develop healthy eating habits from an early age.

Studies by BCRF researchers, Graham Colditz, Walter Willett and others have shown that being overweight early in life–during and before adolescence– increases the risk of benign breast disease, or hyper-proliferation of the breast tissue, which can increase the risk for future breast cancer. Cardiovascular studies have also noted that children as young as two years old can have signs of cardiovascular plaques – early stages of heart disease–when fed a diet high in saturated fats, such as fast foods.

Many of us know from experience that lifestyle changes are harder to make the older we get, but they can have an even bigger impact later in life. We know that people who quit smoking significantly decrease their risk of lung cancer compared to those who don’t. In addition, recent research has shown that weight loss after menopause can decrease the risk of breast cancer in overweight or obese women.  Studies have demonstrated that women with breast cancer at any age may have a worse prognosis if they are overweight or obese.

How to Eat Healthy in 2018

Many government agencies and organizations, including the American Heart Association and American Dietetic Association agree on some very basic guidelines to achieving and maintaining healthy weight:

  • Eat smaller portions
  • Select from a mix of colorful vegetables every day
  • Choose whole grains and unprocessed foods
  • Avoid saturated fats and select fats and oils high in omega 3 fatty acids

Maintaining a healthy weight has many benefits including potentially reducing the risk of breast cancer after menopause. If your goal is to lose a few pounds you gained over the holiday, give yourself about a month to achieve your goal. To lose one pound a week, you will need to reduce calories by about 500/day or 3500kcals/week. If your goal is to generally eat better and be more conscious of what you eat, keeping a food diary has been shown to be very effective in helping people stay on track with their goals.

If you have been diagnosed with breast cancer, maintaining a healthy weight can reduce your risk of breast cancer recurrence.  The American Society of Clinical Oncology (ASCO) has created guidelines for patients and doctors to help patients manage their weight during and after cancer treatment.  Pease discuss diet with your oncologist.

Weight Loss Tools

There are many apps that can help count calories and keep track of exercise. Online tools include the USDA SuperTracker  and American Dietetic Association Both can help you personalize your diet and fitness plan to reach your goals and provide evidence-based information you can trust.

If you need to lose a significant amount of weight, more than 10-15 pounds, discuss your goals and health concerns with your primary care physician. Dieting may not be enough to achieve a healthy weight for those 30 or more pounds overweight.  Bariatric surgery helps many obese people achieve a healthy weight and has been shown to decrease the risk of heart disease and Type II diabetes, but there are risks involved. You can read more about this option at the NIH Institute of Diabetes and Digestive and Kidney Diseases website.

For healthy recipes and menu plans, visit the following websites:

In Part 2 of this series, we’ll take on the physical activity component of a healthy lifestyle.