Skip to main content
Skip to main content

The Big Issue: Breast Cancer and Your Weight

Can breast cancer treatment make you fat?

Weight gain is a reality for many women during breast cancer treatment – yet it is sometimes not addressed by healthcare professionals. Now, we can help you understand why those pounds pile on and how you can shift them. 

So, is it true – does breast cancer treatment make you fat? “Yes!” say huge numbers of Amoena Life readers. “Perhaps,” say the experts. According to Cancer Research UK, for example, fewer than one in ten people puts on weight while taking tamoxifen. Well, here in the Amoena Life editorial office you could have knocked us down with a feather – because if readers’ letters are anything to go by, it would seem that the real statistic is far higher.

Peggy Mellers is just one of a number of readers who have told us of their frustration with post-treatment weight gain. She was in her mid-seventies when diagnosed, so it could not be claimed that being slammed into an early menopause was responsible. “Before my cancer operation I was a size 14. After commencing tamoxifen my dress size increased to 16 and then 18, even though there was no change in my diet,” she says. Peggy eventually gained nearly 30 pounds. She watches her diet, carefully monitoring fat intake, partly because her partner has had a triple heart-bypass, yet still the weight refuses to budge.
Another reader, Victoria Clark, spent a long time on Arimidex, and has gone up to a dress size 20. Despite coming off the drug over a year ago, she has not lost any weight. At one of her annual check-ups, Victoria asked her medical team what could be causing the problem. “My GP just shrugged and said, ‘That’s what happens,’ while at the hospital one doctor told me, ‘It’s better than being dead.’ No-one gave me any help or advice.” 

Middle-age spread – fat or fiction?

Even without the disruption of breast cancer treatment, many women find that as they reach middle-age, they can’t get away with eating as much as they used to without putting on a bit of weight. Often they first notice this extra poundage around their midriff. Although it is highly frustrating, this tendency is quite natural, says the UK’s leading nutritionist specializing in women’s health, Dr. Marilyn Glenville. “Women need estrogen to maintain healthy bones. At menopause, whether it is induced or natural, the body will try to make estrogen to replace that which is lost when the ovaries stop working. It can do that by placing extra fat cells around your middle to act as a manufacturing plant,” she explains. 

“Because of this, in some ways, when you want to stay slim you are fighting against your body’s natural tendencies,” continues Dr. Glenville. “It’s also why women often gain weight during breast cancer treatment, particularly if they are on anti-estrogen drugs.” 

Experts also acknowledge that chemotherapy can trigger weight gain, as the steroids often given as part of the treatment can slow down your metabolism. Sometimes taste buds can be affected, too, and the tendency is to eat more – whether to combat the bad taste, or to load up on foods that still taste good.

Exercise is also known to play a part. While many of the women we speak to are convinced that their treatment contributed to a marked weight gain, they also accept that for a while they were a lot less active. For some, there is also a permanent change of lifestyle, which can make a difference over several months. If you’ve gained weight, you’ll probably acknowledge that some of these factors are partly to blame, but take some deep breaths and relax, because getting stressed about it could be the last thing you want to do. 

Too stressed to be slim? 

Conjure up an image of an anxious person in your mind’s eye. They’re probably skinny with all that worry, aren’t they? But according to Dr. Glenville, stress is another factor in the body’s hoarding of fat stores. 

“The stress of diagnosis and treatment can lead to weight gain, because cortisol, the so-called stress hormone, can affect what you eat,” she explains. “Basically a body under stress wants to keep a fat store in order to protect itself. If we were fighting for our lives, this would be very beneficial in a famine situation.” Not so great, though, if you just want to look good in your jeans. 

So, our hormones – natural or artificial – are against us; our age is against us, and even being stressed can make us fat. You could be forgiven for wondering if there was any hope for your waistline at all. Thankfully, though, there is a way, and it’s all about balance. You’ll also be pleased to know you can forget fad diets once and for all, and running marathons isn’t the answer either. 

A new attitude to food 

As we’ve seen, putting on a little fat around the middle is the body’s way of maintaining bone density as we get older, or when estrogen is scarce. Some women may feel content to get a little plumper, while others are determined to return to their pre-diagnosis weight. Whatever you decide is right for you, it’s vital to be sure you’re still healthy. You can do this by keeping an eye on your waist-to-hip ratio, which should be under 0.8. 

It’s important to remember that we’re dealing here with very ‘active fat’. Dr. Glenville says that it functions like a gland in itself, producing hormones that change your appetite and influence the food choices you make. So at least you know you weren’t imagining those carb cravings! 

For women who’ve had breast cancer, of course, another concern with this type of fat is the possibility of recurrence. With the majority of breast cancers being estrogen-receptor positive, it makes sense to have as little of this estrogen factory around your middle as possible. The challenge is, how? 

Read more about ways to manage your weight with exercise, and improve your overall health.