How cancer and cancer treatments cause weight changes
Cancer treatments can lead to unexpected weight changes. Discover simple, effective ways to manage your weight and feel your best during and after treatment.
What you'll learn by reading this page:
The relationship between cancer and weight changes
The impact of different types of cancer and treatments on weight changes
How cancer can cause weight gain
Managing weight changes during and after treatment
How cancer and cancer treatment cause weight loss
Unintentional weight loss is a common and concerning issue for many cancer patients. Weight loss during cancer is often multifaceted and can be influenced by the specific type of cancer, the treatments, and even the emotional toll that the disease takes. While some weight loss might seem minimal at first, it can quickly escalate and become a major concern for patients and healthcare providers alike. This weight loss can occur not only because of cancer treatments like chemotherapy and radiation but also due to the cancer cells themselves. Cancer cells, in many cases, directly contribute to unintentional weight loss by altering how the body processes and uses nutrients.
"It’s recommended that all cancer patients undergo nutritional screening to ensure that those likely to experience unwanted weight loss are identified and can be directed toward and guided by a nutrition professional such as a dietitian or nutritionist with advanced practice training in oncology."
Lori Drummond
Nutritionist
Cancer treatment side effects that contribute to weight loss
For instance, cancer treatments such as chemotherapy, radiation therapy, surgery, immunotherapy, and stem cell transplantation can cause conditions that contribute significantly to weight loss. Some of these conditions include:
Mouth and throat sores
Mucositis, a common side effect of chemotherapy and radiation, can severely hinder a cancer patient's ability to eat. These painful sores in the mouth and throat occur because treatments not only target cancer cells but also damage healthy cells, including those in the lining of the mouth and throat. This makes eating incredibly painful and contributes to significant weight loss.
Loss of appetite
Often, chemotherapy impacts a person's sense of taste and appetite, making food unappealing. Changes in taste can make it difficult for patients to enjoy food, even when they want to eat, leading to reduced food intake and weight loss.
Diarrhea
Cancer treatments such as chemotherapy, radiation, surgery, and immunotherapy can all trigger diarrhea. Chronic diarrhea can lead to nutrient malabsorption, dehydration, and unintended weight loss if not properly managed.
Nausea and vomiting
A particularly challenging side effect of chemotherapy, radiation, and other cancer treatments is nausea and vomiting. This can occur immediately after treatment or even weeks later. Chemotherapy-induced nausea and vomiting (CINV) is a common issue for patients undergoing high doses of treatment. Additionally, radiation therapy can induce nausea, especially when the treatment targets the brain or abdomen, causing more severe gastrointestinal distress.
Early satiety
Many cancer patients struggle with feeling full after just a few bites of food. This may be due to the cancer itself or the treatments used to combat it. Tumors, particularly those in the gastrointestinal tract or the abdominal cavity, can exert pressure on the stomach, making patients feel full with smaller amounts of food. This sensation can lead to severe reductions in caloric intake.
Constipation
Another significant issue that can lead to a decrease in food consumption is constipation. This can be caused by various factors, such as opioid pain medications commonly prescribed for cancer patients, the physical compression of the bowel by tumors, or medications like antacids and iron. Additionally, decreased physical activity due to the cancer itself or its treatments can worsen constipation, leading to bloating, nausea, and vomiting, which ultimately contribute to weight loss.
Pain
Cancer patients often experience significant pain, which can result in a loss of appetite. This pain might arise from the cancer itself, surgeries, or treatments. When uncontrolled, pain not only affects a patient's quality of life but also their ability to maintain proper nutrition.
Emotional distress
The psychological impact of cancer, including depression and anxiety, can dramatically affect a patient's relationship with food. Depression often leads to a loss of interest in eating, while anxiety may suppress appetite or result in gastrointestinal symptoms like diarrhea. Both of these emotional responses can contribute to further weight loss.
Cancer-related inflammation
Inflammation is another contributor to weight loss in cancer patients. The body's immune system often becomes heightened in response to cancer, releasing proteins that disrupt hunger hormones and alter metabolism. This inflammatory response can make it even more difficult for patients to maintain a healthy weight during treatment.
Struggling with weight changes during or after cancer?
Join our platform to learn how nutrition plays a crucial role in rebuilding your health and vitality.
"While medical treatments play a vital role in battling this disease, the journey toward recovery extends far beyond the hospital or clinic walls. Nutrition plays a crucial role in supporting cancer survivors as they rebuild their health and vitality during conventional therapies and beyond."
Lori Drummond,
Nutritionist
Cancer and losing weight: when to be concerned
Weight loss in cancer patients is not always a red flag, but it becomes a cause for concern under specific circumstances. Rapid and unexplained weight loss can signal a more severe underlying issue, such as dehydration, malnutrition, or worsening cancer. It's essential for patients and caregivers to closely monitor weight changes and consult their healthcare team if they experience:
-
A loss of more than 3 pounds in a week or in less than a week.
-
A loss of more than 5% of their body weight in a year without intentionally trying to lose weight.
-
Persistent feelings of weakness, fatigue, or dizziness.
-
Inability to perform daily activities due to a lack of energy.
-
Difficulty consuming food or fluids, or an inability to eat or drink as much as usual.
These warning signs can indicate that a patient is at risk of serious complications related to malnutrition or dehydration and should be addressed by a healthcare professional.
Managing weight during cancer treatment is a complex and critical part of the healing process. While weight loss is a common challenge, it’s important to recognize when it becomes a serious concern. By working closely with your healthcare team and addressing the physical and emotional factors that contribute to weight changes, you can better manage your nutrition and overall health during treatment.
