Cancer and Weight Loss
Unintentional weight loss is common in cancer patients. Several factors can cause weight loss, including the type of cancer treatment, side effects, physical changes related to the tumor’s location and the emotional impact of cancer. Additionally, cancer cells themselves can play a direct role in weight loss.
Fortunately, there are steps that patients can take to combat cancer-related weight loss.
Treatment-related weight loss
Cancer treatments such as chemotherapy, radiation therapy, surgery, immunotherapy and stem cell transplantation may result in conditions that can cause weight loss. These conditions include:
Mouth and throat sores: Also called mucositis, these are the most common cause of cancer weight loss. Sores are caused by chemotherapy and radiation, which attack cancer cells. Unfortunately, healthy cells are also impacted. These include cells that line the mouth and throat. As a result, many patients develop painful sores in these areas, making it harder for them to eat. Learn more about oral care for cancer patients.
Loss of appetite: In some cases, chemotherapy affects a person’s appetite and sense of taste, making food unappealing. Learn more about appetite changes.
Diarrhea: Chemotherapy, radiation, immunotherapy, surgery and targeted therapy can cause diarrhea. Unintended weight loss can result from persistent or chronic diarrhea. Learn more about bowel management.
Nausea and vomiting:
Nausea and vomiting may occur anywhere from a few hours after treatment to several weeks later. They may be more severe in patients receiving a combination of treatments, such as chemotherapy and radiation therapy together.
Chemotherapy-induced nausea and vomiting (CINV) is an extremely common side effect. Sometimes nausea and vomiting are worse with higher doses of the medications. Not all chemotherapy medications cause nausea and vomiting.
Radiation therapy can cause nausea and vomiting. This is most common during treatment to the brain or the abdomen.
Immunotherapy and targeted therapy may also cause nausea and vomiting.
Other causes of cancer-related weight loss
Early satiety: Many patients complain that they want to eat but then feel full after only a few bites of food. This may be related to cancer treatments and/or the cancer itself. Cancer cells sometimes release hormones that alter the sensation of hunger. Other times, tumors in the gastrointestinal tract or fluid in the abdominal cavity may cause a patient to feel full after only a small amount of food.
Constipation: Constipation in cancer patients can be caused by:
- Opioid pain medication
- External compression or internal obstruction of the bowel by a tumor
- Medications such as antacids and iron
- Abnormal electrolyte levels, including calcium and potassium levels
- Decreased physical activity
Constipation may cause a patient to feel full and lose the desire to eat. It can also cause nausea and vomiting, which leads to decreased nutritional intake. Learn more about bowel management.
Pain: Patients battling cancer often experience pain. Uncontrolled pain can cause decreased appetite. Learn more about cancer pain.
Emotional distress: Depression typically causes a person to lose interest in activities such as eating. It may also lead to lack of motivation to exercise, which helps maintain muscle tone and weight. Anxiety can lead to weight loss by causing a general loss of appetite. Anxiety also can lead to diarrhea, and increase muscle tension and movement, which burns calories. Learn more about stress reduction.
Cancer-related inflammation: Cancer patients often have heightened inflammation. The immune system then releases proteins that hinder the hormones that stimulate appetite and alter metabolism, leading to weight loss.
Treating cancer-related weight loss
Some medications can help stimulate your appetite and ease the side effects of cancer treatment. Your health care team may recommend medications to stimulate the appetite and/or to treat nausea, vomiting and early satiety.
Nutritional support
The best way to give your body enough nutrients is through food. In some cases, though, patients cannot eat or eat enough to maintain their weight. These patients may get nutrition through a tube inserted through the nose or abdomen into the stomach. This is called enteral feeding. It is typically only for short-term use and has risks including aspiration (food or liquid entering the lungs) and unintentional tears in your esophagus, stomach or intestines. These tubes can also be uncomfortable.
Sometimes, patients receive nutrients through a vein instead of eating and drinking if the gastrointestinal tract is not functioning or cannot be used. This is called parenteral nutrition. The safety and effectiveness of this method is not clear, and there are serious potential complications including blood clots and infection.
The use of either enteral feedings or parenteral nutrition should start with a discussion between a patient and their doctor and involve collaboration with a nutrition team.
General tips to manage and prevent weight loss
- There are several steps patients can take on their own to maintain their weight.
- Rather than having three big meals a day, focus on eating frequent, small meals every two to three hours.
- Incorporate supplement drinks to increase your intake of protein and calories. You can also make your own smoothies at home using high-protein milk and/or protein powder. Both animal-based and plant-based protein powders are readily available.
- While it is important to drink plenty of fluids, try to do this in between meals to avoid feeling full easily when eating.
- If water is not appealing, try other sources of fluids. These can include soup, fruits like watermelon and sports drinks (depending on your blood sugar levels). You may also add flavor to water with natural fruit juices or water flavoring drops.
- Eat food rich in both calories and protein, such as avocados, peanut butter, nuts and yogurt.
- Try experimenting with different flavors such as salty, sour and sweet. A flavor that you did not like before may be enjoyable now.
- Ask your doctor about a referral to a nutritionist/dietician who can assess your nutritional status and give advice on increasing your intake of calories and protein.
- Track your bowel movements and report any changes to your health care team.
- If you are having problems chewing and swallowing, ask your doctor about an evaluation by a speech pathologist. Speech pathologists can recommend a diet that is appropriate for your condition.
- Prevention is important when it comes to mouth and throat sores. Your doctor can advise you about whether treatment can cause sores and how to modify your oral hygiene regimen to prevent them.
- Address both physical and emotional symptoms. Talk to your health care team If you experience emotional changes such as prolonged sadness and/or anxiety that are interfering with your day-to-day life or desire to eat.
Cancer treatment side effect: Involuntary weight loss
Whether it’s due to pain from a growing tumor, swallowing difficulties caused by radiation therapy, or the nausea, loss of appetite or mouth sores that are sometimes caused by chemotherapy, involuntary weight loss is a serious side effect of cancer and its treatment for many patients.
But there are other reasons why cancer patients could be losing weight without trying.
We spoke with internal medicine and palliative care specialist Rony Dev, D.O., to learn more about involuntary weight loss and what patients can do to counteract this common side effect. Here’s what he had to say.
What are the most common causes of involuntary weight loss in cancer patients?
The simplest answer is “decreased caloric intake.” They just aren’t eating as much. And when you don’t take in enough calories for your body to maintain itself, weight loss is the result. There are quite a few things that contribute to weight loss in addition to the underlying cancer.
For one thing, the body secretes inflammatory proteins, including “tumor necrosis factor” (TNF), which make people feel bad and typically experience a significant decrease in their appetite.
Trying to control cancer requires a lot of energy, too, and cancer patients’ metabolism is often elevated to accommodate for the increased inflammatory response. That combination alone is enough to cause weight loss, but when you combine it with the appetite-suppressing qualities of pain, changes in the taste of food (often described as being metallic) due to chemotherapy, and the discomfort caused by constipation and reflux issues, the issue of weight loss is often compounded.
Mood disorders, depression and anxiety can also contribute to weight loss. In addition, there are endocrine factors, such as low testosterone, that can cause changes in body composition and a decrease in weight in male patients with certain cancers or on chronic opioid therapy.
What can doctors do to help patients counteract involuntary weight loss?
Fortunately, there are treatments especially for symptoms that can contribute to weight loss. We can use beta-blockers to treat hypermetabolism; antiemetics for combatting nausea; counseling, anxiolytics (drugs used to treat anxiety) and antidepressants for stress and mood disorders; anti-inflammatories to reduce inflammation, and hormonal supplements to replace testosterone in male patients.
What can patients do to manage involuntary weight loss?
Most interventions require a health care provider, so it’s important to communicate with your care team as soon as you notice a problem. They can enlist the help of any specialists you might need, such as a dentist for tooth pain or chewing problems, and a gastroenterologist for help with bowel issues.
Why is it important for cancer patients to get unwanted weight loss under control quickly?
Patients tolerate cancer treatment better and have better responses to it if they can maintain a healthy weight. So, adequate caloric intake is critical to preventing chronic undernourishment.
Unwanted weight loss can also lead to fatigue, which means patients aren’t able to do all of the things they want to do. That causes a lot of distress — not only in patients, but also in their caregivers.
That’s why it’s so important to catch this problem early. If someone loses 5% or more of their total body weight without trying, that’s a big red flag. And we need to start addressing some of those underlying factors right away, before it snowballs.
Is involuntary weight loss more common in patients with certain types of cancers?
Yes. More than 80% of patients with pancreatic cancer will experience unwanted weight loss. It’s fairly common in other gastrointestinal cancers, too. And we’re also more likely to see it in advanced cancers, regardless of the type.
Are there any clinical trials underway related to involuntary weight loss?
Yes. One clinical trial is assessing psychological factors associated with weight loss. It deals with the frequency of cancer-induced anorexia (loss of appetite) and cachexia (wasting disease) in patients with anxiety and depression, and assesses body composition and takes other mitigating factors into account.
A second clinical trial is studying whether a drug called anamorelin can spur weight gain by manipulating the appetite hormone, ghrelin.
What’s the one thing you want cancer patients to know about involuntary weight loss?
Once dramatic weight loss has occurred, it’s very hard to change course. So, seek help as soon as you notice it happening.
Request an appointment at MD Anderson online or by calling 1-877-632-6789.
Weight loss during cancer treatment: 5 do’s and don’ts
The basic formula for weight loss is no secret: burn more calories than you consume. But actually doing that can feel like cracking an impossible code. Add cancer into the equation, and weight loss feels infinitely more complicated.
We know that excess body weight is a risk factor for more than 10 types of cancer. For some, this knowledge makes weight loss feel especially urgent after being diagnosed with cancer. Others struggle to keep weight on due to cancer itself or treatment-related side effects. For others still, the stress of cancer means weight loss is the furthest thing from their mind.
To put it mildly, there’s a lot to unpack on the topic of weight loss during cancer treatment. To help clear up the confusion, we spoke with clinical dietitian Reeve Reinsborough. Read on for some do's and don’ts to help you decide if losing weight during cancer treatment is right for you and, if so, how to do so safely.
Don’t approach weight loss alone
Trying to lose weight on your own can be especially tricky during cancer treatment. There are so many variables to consider. That’s why Reinsborough stresses the importance of working with your care team to determine if you need to lose weight.
“First, talk with your primary physician or a dietitian to determine if weight loss would benefit you and your health goals,” she says.
While you may want to lose weight, you don’t want to lose your strength and muscle mass in the process. If your care team recommends losing weight, Reinsborough recommends partnering with a dietitian throughout the process.
“Patients undergoing cancer treatment need individualized care both before, during and after their treatments to healthily lose weight,” she says.
Each MD Anderson patient has a registered dietitian on their care team who can help answer questions related to nutrition and weight.
Do know that weight loss looks different during cancer treatment
Life can look and feel a lot different after a cancer diagnosis. Even weight loss during cancer seems to go by different rules.
“The cancer population is completely different than the general public as far as a healthy weight loss journey goes. Although the general idea for weight loss is ‘less calories in, more calories exerted,’ it is important to remember the increased stress that patients go through during treatment even if they are less active than they were previously,” Reinsborough says.
So, if you have cancer, how do you know how many calories to eat a day? Factors like age, gender, weight and height are used to help predict daily calorie intake. But, for cancer patients, additional factors like the type of treatment you are on can change your nutritional needs. For example, she notes that people receiving radiation therapy may have higher calorie or protein needs. That’s why it can help to talk to a dietitian or doctor about losing weight during treatment.
Don’t use only BMI or the scale to determine if you should lose weight
Body Mass Index (BMI) calculators are a popular way to get an idea of if you are underweight, overweight or at a healthy weight; all you need to do is plug in your height and weight. But the simplicity of BMI calculators can also be a weakness as they fail to consider other factors that might impact weight. The same goes for the number on your scale.
“Your BMI or weight should not be the only indicator that weight loss would be beneficial,” Reinsborough says.
Instead, she recommends speaking to your care team about your health goals. A few reasons she says weight loss may be recommended during cancer treatment include the following:
- Reduce the risk of complications due to health conditions such as:
- Hypertension
- Type 2 diabetes
- High cholesterol
- Arthritis
- Joint pain
- Reduce complications during surgery
Do focus on maintaining your weight
Cancer and cancer treatment can take a lot out of you, both mentally and physically. That’s why it’s so important to eat healthy foods that provide a variety of nutrients.
MD Anderson dietitians recommend eating meals rich in whole grains, vegetables, fruits, beans, nuts and seeds. Aim to fill two-thirds of your plate with whole grains, vegetables, fruits, beans, nuts and seeds. The remaining one-third can be lean animal protein or plant-based protein.
RELATED: Healthy foods to eat during cancer treatment
While the idea of your scale being stuck in one place is a common concern among people trying to lose weight, this consistency isn’t a bad thing during cancer treatment. In fact, many people in cancer treatment focus on maintaining their weight.
This doesn’t mean that the scale shows the exact same number every time you weigh yourself. Rather, it means that fluctuations are minor: think 2 or 3 pounds in each direction, Reinsborough says. For example, a 140-pound woman might notice her weight varying from 137 to 143 pounds depending on the day.
Don’t ignore it if you are losing weight without trying
While the idea of weight simply melting off without any effort may be exciting for some, effortless weight loss during cancer treatment should raise a red flag.
“Unintentional weight loss during cancer treatments is very common and can lead to increased risk for several complications or inability to continue with the treatment itself,” Reinsborough says, adding that if you unintentionally lost weight before treatment, it isn’t recommended for you to keep losing weight.
Curious as to why weight maintenance or even gaining weight may be recommended for some cancer patients? It all comes down to safety. Reinsborough explains that maintaining or gaining weight during treatment can help reduce the risk of negative outcomes such as muscle loss, serious falls and prolonged hospital stays.
Tell your care team if you find yourself losing weight without trying so you can make a plan to ensure you get the nutrition your body needs during treatment.
“Focus on providing your body with enough energy and the strength it will need,” she says.
Do tell your care team if you are on weight loss medication
Be sure to tell your care team if you are using a type of injectable weight-loss medication called GLP-1 agonists. This is because these drugs may impact certain cancer treatments and side effects.
For example, endocrine neoplasia and hormonal disorders specialist Sonali Thosani, M.D., notes GLP-1 products may make treatment side effects like nausea and vomiting harder to manage. Additionally, GLP-1 drugs can lead to significant weight loss and muscle loss which may make chemotherapy tougher to tolerate.
RELATED: Weight loss injections and cancer: 6 questions, answered
So, if you do use weight loss drugs, tell your care team so they can advise you on the safest path forward.
Request an appointment at MD Anderson online or call 1-877-632-6789.