Types

Weight loss with cancer

Weight loss is common in people with cancer. It might be one of the reasons why you first go to the doctor. There are several causes of weight loss and your doctor can treat many of these.

Weight loss and cancer

Losing weight is often associated with a loss of appetite. But this is not the only cause. For people with cancer, other causes are:

pain
a swollen tummy (abdomen)
feeling and being sick (nausea and vomiting)
difficulty swallowing
feeling full because of a swollen (enlarged) liver
a blocked bowel
high levels of calcium in the blood
not being able to absorb nutrients from food (malabsorption)

Cachexia

Some people may lose weight despite eating normally. This is called cachexia (pronounced kak-ex-ee-a). With cachexia, your body may not be absorbing all the fat, protein and carbohydrate from the food you eat. And you may be burning calories faster than normal.

People with cachexia lose muscle and often fat too. Scientists think that cancer releases chemicals into the blood. The chemicals contribute to the loss of fat and muscle.

Weight loss can depend on cancer type

Weight loss is more common in some cancer types.

About 60 out of 100 people with lung cancer (60%) have a loss of appetite and significant weight loss at the time of their diagnosis. In people with upper gastrointestinal cancer, this number is 80 out of 100 people (80%). Upper gastrointestinal cancers include:

food pipe (oesophagus) cancer
stomach cancer
small bowel cancer
pancreatic cancer
liver cancer (including primary and secondary liver cancers, bile duct and gallbladder cancer)

Monitoring your weight

Your doctor will want to find out the cause if you are losing weight without dieting.

You can:

weigh yourself once a week at the same time, wearing the same clothes
keep an eye on how tight or loose your clothes, watch or rings are if you don't have scales

Let your healthcare team know if you are worried about changes in your weight.

Tips for putting on weight

Last reviewed: 13 Sept 2023

Next review due: 14 Sept 2026

Managing diet problems

Medicines, soft diets, adding calories to your diet or tube feeding are some of the ways to manage diet problems.

Difficulty swallowing

Some cancers and their treatments can cause a sore mouth and throat. This can make chewing and swallowing difficult.

Types of diet problems

The side effects of cancer and its treatments might cause problems with your eating, digestion and weight.

Your feelings about diet problems

Having diet problems when you have cancer can affect you emotionally. But there are things you can do to help you cope.

Resources and support for diet problems

There are lots of organisations, support groups and other resources to help you cope with diet problems caused by cancer and its treatment.

Diet problems main page

Cancer and its treatment can cause eating and drinking difficulties in some people. But there are people that can help and things you can do to help you cope.