Man drinking water as he takes PERT and eats a sandwich

Managing diet and weight loss with tips from a dietitian

Our nurses
11 April 2023

Hello, we are Lynne and Jeni, specialist pancreatic cancer nurses. We are here to help those with pancreatic cancer deal with symptoms as best as possible.

In this blog we wanted to give you some more detailed information on one of the most common issues – digestion, weight loss and diabetes.

Problems with digestion

Having pancreatic cancer can affect what you eat and how well you digest your food. The pancreas produces enzymes, which break down food so that all the nutrients in it are absorbed into your body. Nutrients include protein, carbohydrates, fats, vitamins and minerals. Pancreatic cancer can reduce the amount of enzymes your body makes, and this causes problems with digestion.

It is common for people with pancreatic cancer to get symptoms caused by problems digesting food, such as:

  • losing your appetite
  • losing weight, or struggling to put weight back on
  • indigestion or heartburn
  • runny poo (diarrhoea)
  • finding it harder to poo (constipation)
  • pale, oily, floating poo (steatorrhoea)
  • tummy pain or discomfort
  • bloating or wind
  • feeling full up quickly
  • feeling sick needing to poo quickly, especially after eating.

Read more about these diet symptoms.

Many of these problems can be managed with pancreatic enzyme replacement therapy (PERT). You may have heard of Creon or Nutrizym, which are common types of PERT.

PERT is capsules you take with your food. It helps to replace the enzymes that your pancreas would normally make. The capsules help you to digest your food and absorb all the calories and nutrients you need. Taking PERT can help manage digestion symptoms and make a big difference to how you feel. Most people with pancreatic cancer will benefit from taking PERT.

If you are someone who has had surgery to remove all or part of the pancreas, this may also affect the number of enzymes that the pancreas makes. So you may need to take PERT.

The pancreas also produces hormones called insulin and glucagon to control blood sugar levels in the body. Pancreatic cancer can reduce the amount of these hormones, which can cause diabetes.

In this video, Jeni talks about the benefits of PERT and how to take it properly.

We asked Lindsay Carnie, Specialist Oncology Research Dietitian at The Christie in Manchester, for her tips on taking PERT.

“If you are taking PERT, it is important to take them with all meals, snacks and milky drinks including oral nutritional supplements. If you are taking more than one capsule take half with the first mouthful of food or drink and then take the rest throughout the meal or drink.

If you are struggling to remember to take your enzymes, try leaving a note on your fridge or cupboard, or set a reminder on your phone for around mealtimes. Don’t forget to have them with you when leaving the house, but don’t keep them in your trouser pocket or a warm glove compartment as this may stop them from working properly.”

If you are experiencing any symptoms related to diet or require advice about PERT, get help. If you have a dietitian involved in your care give them a call. Your medical team or GP will also be able to give you advice and support. And of course you can contact us free on the Support Line or come to one of our support sessions about nutrition and PERT.

Weight loss

Losing weight is a common symptom of pancreatic cancer. It can affect how you deal with the symptoms of cancer and your treatment. It can also be very upsetting and affect how you feel generally.

Getting medical advice to help manage your weight loss is really important. If you have a dietitian, they should be able to advise you on this and offer you support. You could also go to your hospital team or GP. They can all help you make changes to your diet so you can get more calories and protein. You may be offered nutritional supplements which are often drinks or powders. These have extra calories, protein and vitamins in them. Take PERT every time you eat food, and when you have nutritional supplements or milky drinks. This may help you maintain your weight.

If you have lost weight quickly, you may notice that you have lost some of the strength in your muscles. Having more protein in your diet and doing gentle physical activity can help rebuild this muscle strength. This can help you to feel better and have more energy.

A word of warning. There is a lot of bad advice online, making claims that certain types of diets or supplements can help people with cancer. More often than not, these claims are not scientific, with no evidence to support them. If you have pancreatic cancer it’s important not to cut anything out of your diet, or take any supplements, without speaking to your dietitian, hospital team or GP first.


Diabetes is a condition where the amount of sugar (glucose) in your blood (your blood sugar level) is too high. This is called hyperglycaemia. The pancreas plays an important role in controlling your blood sugar level, so having pancreatic cancer can cause diabetes. This can also happen following surgery to remove the cancer. If you already had diabetes, pancreatic cancer can change how the diabetes is managed.

Symptoms of diabetes include:

  • feeling thirsty
  • wanting to urinate (pee) often (more so at night)
  • tiredness
  • confusion
  • weight loss
  • blurred vision.

If you have these symptoms please get in touch with your medical team or GP for advice and support.

If you are diagnosed with diabetes, you may see a specialist dietitian to help you manage your diabetes. If you haven’t seen a specialist dietitian, ask your doctor or nurse to refer you to one. You may also see a diabetes specialist nurse who will teach you how to monitor your blood sugar levels and help manage your diabetes medicine. Your GP may also help manage your diabetes. You may need to monitor your blood sugar level regularly, and take tablets or have insulin injections to control your diabetes.

There are different types of diabetes, and information on the internet about changing your diet may not be right for you because of pancreatic cancer. If you have lost weight or are struggling to eat, you may need more calories in your diet to help you put weight back on. This may include eating foods that increase your blood sugar level. Your diabetes will need to be managed around this. Make sure you speak to your nurse, doctor or dietitian about this.

Lindsay gives some further advice on diet and diabetes with pancreatic cancer.

“The main focus at this time should be to stop you from losing more weight, as this can affect whether you can have treatment or how you tolerate it. You should try to have a ‘little and often’ approach to eating, aiming for a high calorie, high protein diet. Your diabetes should be managed around what you are able to eat. Please speak with your dietitian, diabetes nurse or hospital team if you have any concerns.”

Managing diabetes if you have pancreatic cancer can be difficult and confusing. If you have any questions, speak to your dietitian, diabetes nurse or hospital team. You can also speak to our specialist nurses on our free Support Line. We also have support and information on our website about managing diabetes if you have pancreatic cancer. For example, we have a webinar on Pancreatic Cancer and Diabetes, presented by diabetes specialists and our specialist pancreatic cancer nurses. We talk about the different types of diabetes, share practical information on managing diabetes alongside pancreatic cancer, and explain the support that’s available for you and your family. You can watch a recording of the webinar any time or sign up to go to other webinars on our support pages.

If you have any questions about pancreatic cancer, your treatment or care, you can of course speak to one of our nurse specialists on the Support Line.

Remember – you are not alone. Pancreatic Cancer UK is here to support you through this challenging time.

Lynne & Jeni

Nurses Lynne (left) and Jeni (right)

First published: May 2020

Updated: April 2023

To be reviewed: April 2025