Body Weight and Breast Cancer

After I finished chemotherapy in 2011, my medical oncologist began expressing concern about my weight. Overweight is usually defined as a Body Mass Index (BMI) over 25.  In postmenopausal women, overweight is considered a risk factor for estrogen receptor-positive breast cancer recurrence (but not for estrogen receptor-negative breast cancer),¹ After menopause a woman’s ovaries stop producing estrogen and the primary source for estrogen is her body fat. Therefore, a woman with a higher level of body fat during the post-menopausal years would be expected to have a higher level of body estrogens than a comparatively lean woman. Estrogen can make hormone-receptor-positive breast cancers develop and grow.

I had never been overweight until I reached menopause in my 50s, and then I rather suddenly put on 50 pounds. My father told me to have my thyroid checked because he had become hypothyroid and overweight when he was my age. I checked, and he was right; I was hypothyroid. I started taking thyroid hormones, and I also changed to a healthier diet. At that point, I stopped gaining weight, but I did not lose the weight I had already gained.

Scientists had long known that lower estrogen levels after menopause can cause fat storage to shift from the hips and thighs to the abdomen. A groundbreaking study, co-authored by the Mayo Clinic, determined the reason: Proteins, revved up by the estrogen drop, cause fat cells to store more fat. And to make things worse, these cellular changes also slow down fat-burning by the body.² Unfortunately, the research didn’t provide any weight-loss solutions, but it reportedly brought a sense of relief to many middle-aged women who now knew why they were fighting an often losing battle against the dreaded “post-meno belly.”

In my case, it did not bring relief. It brought on my two now-familiar Kubler-Ross stages of grief: denial and anger. Here I was taking anti-estrogen hormones, which would have the effect of making me fatter, and at the same time I was being told to lose weight!

I had, of course, heard that overweight is unhealthy, but I never believed it, at least not at the level of mild obesity, because my father died, still happily overweight, at age 99 ½. My mother lost her extra weight unintentionally when her diabetes got out of control, but even so, she lived until 86. Since I do not have diabetes or even prediabetes, I expected to live longer than that. Until I got cancer I thought I was healthy. I did not have high blood pressure, high cholesterol, or anything else related to overweight; I exercised regularly, and I had no trouble keeping up with my thinner friends. Everyone in my immediate family had been of normal weight until we reached old age, and the family pattern of gaining weight late in life seemed normal and healthy to me.

Because nature makes old people gain weight, I thought we were supposed to be plump. I even thought it was safer; it gives us something in reserve in case we get sick. I had a friend who was diagnosed with Stage 4 lymphoma. She was given an experimental drug that seems to have saved her life, but it had a side effect of making her lose 50 pounds very rapidly. She was thankful she had the extra pounds; otherwise she would most likely be dead now. (Happily, she lost her 50 at the same time I gained mine, and we exchanged wardrobes.)

I searched on the Internet, and I found that science is on my side!  The research is summarized in The Obesity Paradox, a book by renowned cardiologist Carl Lavie, MD.³ The paradox refers to the fact that, while it is true that obesity predisposes people to diseases like diabetes and heart disease, it is also true that when they get sick (and we all will), people in the overweight to moderately obese (Class I obesity) group live longer than those of normal weight or less. Dr. Lavie encountered these surprising results in his heart disease patients, but the same held true for patients with cancer, diabetes, kidney disease, arthritis, and even HIV infections. Overweight and moderately obese patients with certain chronic diseases, from heart disease and arthritis to advanced cancer and even AIDS, often do better and live longer than normal-weight patients with the same illnesses.

The following table shows the weight classifications defined by the World Health Organizations (WHO):⁴

Mortality turns out to be a U-shaped curve: The underweight and the morbidly obese die soonest, and the normal weight are next. The overweight to moderately obese (BMI 25 to 34) live the longest. This remains true even when researchers rule out lowered weight that could be caused by things like preexisting illnesses or smoking. For the elderly population, the results were more pronounced. Even before these studies, many doctors recommended that an ideal BMI for the elderly (defined variously by different researchers as those over 50, over 60, or over 70) would be between 25 and 27. Apparently extra weight is really lifesaving when the elderly get sick.

For years doctors thought that the healthiest BMI for the non-elderly was around 23, but in 2005 Dr. Katherine Flegal and co-authors from CDC and NIH published a study in JAMA (Journal of the American Medical Association) which found that being overweight was associated with lower mortality than normal weight and also validated the U-shaped curve.⁵ Of course, her findings caused an uproar, and mainstream medicine criticized her findings. However, the CDC accepted Dr. Flegal’s figures as correct, and awarded her the Charles C. Shepard Science Award.

Next came a 2009 study examining the relationship between BMI and death among 11,326 adults in Canada over a 12-year period. Researchers found that underweight people had the highest risk of dying, and the extremely obese had the second highest risk. Overweight people had a lower risk of dying than those of normal weight. For this study, researchers used data from the National Population Health Survey conducted by Statistics Canada every two years. During the study period, from 1994/1995 through 2006/2007, underweight people were 70 percent more likely than people of normal weight to die, and extremely obese people were 36 percent more likely to die. But overweight individuals were 17 percent less likely to die. The authors controlled for factors such as age, sex, physical activity, and smoking.⁶

In 2013 Dr. Flegal was the lead author of a much larger and more comprehensive study, and it controlled for factors that could skew the results, such as smoking, age, and gender. A systematic review and meta-analysis of studies from all over the world, the study included more than 2.88 million participants and more than 270,000 deaths. The results were the same. The lowest mortality rates were not in the ideal BMI group. It was the overweight group that had the lowest mortality rate, with a statistically significant six percent reduction over the ideal group. In fact, the mortality rate of the ideal group was actually the same as the Class 1 (or mildly obese) group. Classes 2 and 3 did show a significant risk, but individuals in those groups represent a small fraction of the 67 percent of all Americans who are classified as either overweight or obese.⁷ At some level of increasing weight, there is always going to be an increased risk of mortality, but where that boundary is, is far from clear. Some still resist her findings, but many researchers accept the results of Dr. Flegal’s 2005 and 2013 papers and see them as an illustration of the obesity paradox. I imagine that the reason this information is not common knowledge is because many people fall prey to the Semmelweis reflex, which is the tendency to reject new evidence or new knowledge because it contradicts established norms, beliefs, or paradigms.⁸ It might also threaten some business models.

Based on her study. Dr. Flegal found that the healthiest BMI is between 25 and 30. It is regrettable that this information is not more widely known because of the huge social implications for these findings. This research is important for those struggling to lose weight through potentially dangerous therapies like crash dieting, gastric bypass and dangerous drugs or supplements. It’s also important for those at the underweight end of the spectrum. UCLA computed the BMIs for 10 famous supermodels and 10 top actresses.⁹ All 10 of the supermodels and 8 of the actresses had BMIs below 18.5, and as low as 14.64. (None of the top male models were underweight.) Models and actresses are rarely attacked for being unhealthy and poor role models for the young. Instead, all the focus is on bashing the overweight. In addition to leading to eating disorders and shortened lifespans, our culture’s skewed version of female beauty can lead to major issues with self-acceptance for girls and young women.

However, there is some good news.  In 2014, the Smart BMI (SBMI) calculator was launched as a way of correcting for the problems with the regular BMI.¹⁰  Based on published BMI and health-risk data for more than three million people, it results in higher BMI limits for women, for young adults, and for persons older than seventy years of age.  I hope it becomes widely used.

According to Dr. Lavie, the American cultural idea that slim people are fit and fat people are unfit simply isn’t true. In fact, using objective measures, many fat people are fit and many slim people are not. Dr Lavie believes that using BMI as an indicator of health is a mistake. It would be better to use data from things like blood sugar, cholesterol, markers of inflammation, and relevant hormones.

The message of Dr. Lavie’s book is that doctors need to work with their patients to achieve proper fitness levels instead of assuming that the thin ones are fit and that the fat ones need to lose weight. Fitness can be determined by checking patients’ vital signs and drawing blood at an annual checkup. The blood can be tested for blood counts, values for certain proteins and electrolytes, markers of inflammation, some hormonal values, Vitamin D levels, and cholesterol and triglyceride levels. (The specific tests are listed in his book, and they overlap with the ones I get from my integrative oncologist.) Less than ideal levels should be improved with diet and supplements or drugs as needed. Research shows that more than half of “overweight” and about one-third of mildly and moderately obese people are metabolically healthy, which amounts to about 56 million Americans. Dr. Lavie stresses that obese individuals who are metabolically normal do not improve their health with weight loss. However, he cautions that if you are painfully thin (BMI less than 18.5) or morbidly obese (BMI over 40), you will find it extremely difficult to be fit.

Most people can consider themselves fairly fit if they can climb a few flights of stairs without much trouble and walk a mile in about 15 minutes. Muscle strength is probably acceptable if you can do normal activities like climbing stairs and lifting heavy objects like children and grocery bags.

For most people, the most important factor in both BMI and fitness levels is diet. Of course, everyone should eat food that is natural and wholesome, low in trans fats, and not very high in salt and sugar, such as the Mediterranean diet. They should also exercise; among other benefits, exercise lowers cancer risk by reducing levels of both insulin and estrogen. Interestingly, the effects of exercise on mortality can also be expressed as U shaped curve. Those who exercise too little and those who exercise too much both die sooner than those who exercise moderately. According to Dr. Lavie, the majority of cardiorespiratory benefits can be achieved by a brisk 20 to 30 minute daily walk. The ideal dose of vigorous exercise is 30 to 60 minutes at least four or five times a week. Walking is healthier than running, mainly because it’s hard to overdo walking. Dr. Lavie cautions, however, that it is not safe to be sedentary the rest of the day; those who sit at a desk should get up and move for a few minutes at least once an hour. In addition, he recommends working the big muscle groups twice weekly with resistance training. Stretching is also important.

According to Dr. Lavie’s standards I was healthy. Thanks to the guidance of my integrative oncologist, I was metabolically normal. I ate the recommended diet, and I did the recommended exercise.

In addition to not believing that overweight is unhealthy, I also questioned whether there was really more breast cancer among people who are overweight. Because of my attendance at the Cancer Support Community, I had seen a great number of people with breast cancer, and I was usually the only overweight person in my support group. If anything, breast cancer patients seemed to me thinner rather than fatter than average, even though many had undergone chemotherapy, which usually causes weight gain. I decided to search the literature to find out whether people with estrogen receptor-positive (ER+) breast cancer were fatter than average. Sadly, this time the science was not on my side. There was a correlation between ER+ breast cancer and overweight. Of course, the researchers did not consider whether or not the overweight patients were metabolically fit. In fact, they mentioned that many of the overweight individuals had a higher prevalence of dysregulation of metabolic factors (e.g. glucose, insulin, insulin resistance, C-reactive protein, etc.) A study published in the Journal of the National Cancer Institute concluded that it is not obesity per se that is a risk factor for breast cancer, but rather the high insulin levels that tend to be associated with excess weight.¹¹ There was no way to know whether the results would also apply to healthy overweight people who, like me, don’t have those metabolic issues. However, I had to reluctantly conclude that I should play it safe and assume that they do.

My denial and anger, I suppose, was my way of trying to avoid having to make any further changes to my eating habits. I thought I had already done enough. It was bad enough that my cancer represented a loss of my health and possibly of years of my life. I just did not want to also face the loss of one of the principal sources of enjoyment of whatever life remained. It really hurt.

However, I had to face it eventually. I tried to figure out what I was willing to change and what I was not willing to change. I thought about how I would feel if I did not follow the instructions and then had a cancer recurrence. Then I thought about how I would feel if I deprived myself of my beloved food and drink and still got a cancer recurrence. There were a lot of factors to consider.

I knew that, for me, a diet would not work. Whenever I have deprived myself for a period of time, I might lose weight, but eventually I would quit depriving myself, and the lost pounds would promptly return. So I had to figure out a way to lose weight while still eating whatever I wanted in the quantity I wanted. I didn’t know how to do that, but a friend recommended a free website called myfitnesspal.com, available online and on smartphones, that allows you to enter your food and exercise. I thought that knowing what I was consuming and what I was burning might be a good place to start. I used it off and on, and eventually I developed a method of using it that works for me. I record all my food and exercise every day unless I am traveling, in which case I skip it. The website also has a place to enter my weight, and I do that in a special way. I only enter my weight when it has gone down. For example, if I started at 100 lbs., I would not record again until I reached 99, no matter how long it took. By ignoring the ups and downs, I have a graph that goes in only one direction: down, and I think that has a psychological benefit for me. My weight would usually go up after a trip, but I did not record it until it reached at least a pound lower than the previously recorded weight, so it didn’t bother me. There are foods I am not allowed to eat because they promote cancer, but other than those, I eat whatever I want in the quantity I want, and I overeat whenever I feel like it. To date I have lost about 25 lbs. and have a BMI of 27.5, which still leaves me 15 to 20 pounds overweight according to regular BMI calculators but puts me right in the middle of the of the ideal range if I use the Smart BMI (SBMI) calculator, which takes age into account.  Since I am not depriving myself, I don’t really understand the reason for the loss. Maybe having to record my food makes me more aware of what I am eating. Perhaps because I have to remember what I ate in order to record it, I am less likely to mindlessly eat everything that’s in front of me. It could also be because I am eating fewer animal products, according to the instructions from my integrative oncologist. In any case, recording my food and exercise is not difficult for me, and I don’t resent doing it. I hope that this method will continue working for me, since I can’t think of any acceptable alternative.

1. Suzuki, Reiko, Nicola Orsini, Shigehira Saji, Timothy J. Key, and Alicja Wolk. “Body Weight and Incidence of Breast Cancer Defined by Estrogen and Progesterone Receptor Status-A Meta-analysis.” International Journal of Cancer Int. J. Cancer 124, no. 3 (2009): 698-712. (Go back)

2. Santosa, S., and M. D. Jensen. “Adipocyte Fatty Acid Storage Factors Enhance Subcutaneous Fat Storage in Postmenopausal Women.” Diabetes 62, no. 3 (2012): 775-82. (Go back)

3.  Carl J. Lavie, The Obesity Paradox, New York: Hudson Street Press, 2014. (Go back)

4. You can find out your BMI by using any of the many BMI Calculators on the Internet, for example: http://www.nhlbi.nih.gov/health/educational/lose_wt/BMI/bmicalc.htm (Go back)

5. Flegal, Katherine M. “Excess Deaths Associated With Underweight, Overweight, and Obesity.” Jama 293, no. 15 (2005): 1861. (Go back)

6. Orpana, Heather M., Jean-Marie Berthelot, Mark S. Kaplan, David H. Feeny, Bentson Mcfarland, and Nancy A. Ross. “BMI and Mortality: Results From a National Longitudinal Study of Canadian Adults.” Obesity 18, no. 1 (2010): 214-18. (Go back)

7. Flegal, Katherine M., Brian K. Kit, Heather Orpana, and Barry I. Graubard. “Association of All-Cause Mortality With Overweight and Obesity Using Standard Body Mass Index Categories.” Jama 309, no. 1 (2013): 71. (Go back)

8. According to Wikipedia, the term originated from the story of Ignaz Semmelweis, who discovered that childbed fever mortality rates reduced ten-fold when doctors washed their hands with a chlorine solution between patients and, most in particular, after an autopsy (the institution where Semmelweis worked, a university hospital, performed autopsies on every deceased patient). Semmelweis’s decision stopped the ongoing contamination of patients— mostly pregnant women—with “cadaverous particles.” His hand-washing suggestions were rejected by his contemporaries, often for non-medical reasons. For instance, some doctors refused to believe that a gentleman’s hands could transmit disease. (Go back)

9.  Accessed April 22, 2016. http://www.stat.ucla.edu/~vlew/stat10/archival/fa02/handouts/modeling.pdf (Go back)

10. Accessed August 22, 2018.  https://www.smartbmicalculator.com (Go back)

11. Gunter, M. J., T. E. Rohan, and H. D. Strickler. “Response: Re: Insulin, Insulin-like Growth Factor-I, and Risk of Breast Cancer in Postmenopausal Women.” JNCI Journal of the National Cancer Institute 101, no. 14 (2009): 1031-032. (Go back)