The ‘ups and downs’ of weight with cancer

Published: 25 Sep 2019

Many people with cancer experience unexplained and rapid weight loss or gain at some point.  According to the American Society of Clinical Oncology, when first diagnosed with cancer, about 40 percent of people report an unexplained weight loss.  However, more than half of women with breast cancer experience weight gain during the course of their treatment.  Slight changes in weight are generally not a problem. But significant weight gain or loss can affect a person's health and ability to recover after treatment.


Weight loss with cancer

According to the American Cancer Society, an unexplained weight loss of 10 pounds or more could be the first sign of cancer. 

Whilst most cases of unexplained weight loss are not caused by cancer, you should still go to your doctor. It could be down to a number of other conditions such as celiac disease, Crohn's disease, ulcerative colitis, peptic ulcers, stress or depression – all of them serious in their own right and need treatment.  But it could also be down to cancer – and an early diagnosis is far more treatable than a late one.

According to Cancer Research UK, 80 percent of people with pancreatic, esophageal or stomach cancer and 60 percent of people with lung cancer, lose a significant amount of weight by the time they’re diagnosed. Other cancers, such as ovarian cancer, are more likely to cause weight loss when a tumor grows large enough to press on the stomach making you feel fuller, faster.

Cancer treatments such as radiation and chemotherapy can also lead to weight loss because of these well-documented side-effects:

Cancer can also cause inflammation, as part of your body's immune response to a tumor, which produces pro-inflammatory cytokines and alters your body’s metabolism. This disrupts the hormones that regulate your appetite. It also increases the breakdown of fat and muscle.  In addition, a growing tumor uses a significant amount of your body’s energy, which may increase your resting energy expenditure (REE). REE is how much energy your body burns at rest.

Significant weight gain or loss during treatment can be linked to a poorer chance of recovery so it’s important to take steps to try to stabilize your weight. Talk with your health care team about any issues and symptoms you experience and how to alleviate them.

How to gain weight with cancer

Weight gain with cancer

Whilst it’s more common to lose weight with cancer, some people gain. Weight gain can be just as dangerous as being undernourished because it can lead to other serious health conditions including high blood pressure, diabetes, and heart problems.  There are many factors involved:

How to lose weight with cancer

Managing fluid retention

Swelling (edema) is another symptom of cancer that can lead to weight gain and feel bloated and uncomfortable.  To help alleviate the problem you can:

If you are experiencing weight changes due to cancer or chemo join the Facebook Chemotherapy Support Group.   You’ll find friendly support and advice from 6000 people worldwide, all fighting cancer and undergoing chemo right now.