You might not often think about your pancreas, a leaf-shaped gland tucked behind your stomach, but it plays a crucial role in digestion and blood-sugar control. Pancreatic cancer occurs when abnormal cells in this gland start to divide uncontrollably, forming a tumour that can invade nearby tissues and spread elsewhere.
Carrying excess weight is a recognised risk factor i.e., for every 5 kg/m² increase in your body-mass index, your chance of developing pancreatic cancer rises by around 10% (and obese adults may face up to a 19% higher risk).1 Conversely, unexplained weight loss is often one of the earliest warning signs, since tumours can block digestive enzymes and trigger a metabolic syndrome (cachexia) that rapidly consumes both fat and muscle.2,3
Thus, because weight can both contribute to and signal pancreatic cancer, it’s important to recognise how the two are linked. This article aims to review the relationship of pancreatic cancer to weight, examining why higher body weight raises your risk and why weight loss may be a red flag.
The pancreas is a large gland that is located in the back of the abdomen. It is a part of both the digestive system and the endocrine system. The pancreas is around 15 cm long. It produces a digestive fluid called pancreatic juice that contains enzymes and hormones, such as insulin and glucagon that aid digestion by breaking down foods into an absorbable form that can be used by the body.
There are two main types of pancreatic cancer: neuroendocrine cancers and exocrine cancers. This division is based on the cells where the cancer originates. Exocrine pancreatic cancer develops from exocrine cells, which make up the exocrine gland and ducts of the pancreas, whereas neuroendocrine cancers occur in the neuroendocrine cells.
Pancreatic ductal adenocarcinoma is the most common type of exocrine cancer. This occurs in the lining of the ducts of the pancreas and also from the cells that carry digestive enzymes out of the pancreas. A rarer type of exocrine cancer is pancreatic squamous cell carcinoma, which makes up 1-4 percent of exocrine cancers. It is rare and more aggressive with a history of poor prognosis.4
Smoking increases the risk of developing pancreatic cancer. The chance of getting pancreatic cancer is twice as high for smokers when compared to non-smokers. In the United Kingdom, smoking is the cause of about 20% of pancreatic cancers and is considered the most important modifiable risk factor.5 Cigar smoking and smokeless tobacco also increases the risk of cancer.
Being overweight or obese is another risk for pancreatic cancer. You are about 12% more likely to develop pancreatic cancer if you are overweight.5 This makes excess body fat the third-largest modifiable risk factor after smoking and poor diet. In the United Kingdom, people assigned female at birth (AFAB) who carry most of that weight around their waist confers them to a 20-37% higher risk versus healthy-weight peers.6
In the general population, a study found that each 5-point rise in BMI boosts pancreatic cancer risk by about 10%, and each 10 cm increase in waist circumference by about 11%.7
Being diabetic also increases the risk of pancreatic cancer. About 6% of pancreatic cancer cases are due to diabetes.
Inflammation of the pancreas (pancreatitis) is a risk factor for pancreatic cancer. Lifestyle factors such as excessive alcohol consumption can cause chronic pancreatitis.
Cancer-causing substances (carcinogens) such as exposure to chemicals or other carcinogens, increases the risk of developing cancer.
Obesity is a well-documented risk factor for developing pancreatic cancer. However, individuals typically present with involuntary weight loss, not weight gain, once the disease is advanced. As the cancer progresses to an advanced stage, the body shows many symptoms, some of which are listed below:
Weight loss is the most consistent early warning sign prompting clinical evaluation in pancreatic cancers. Pancreatic cancers induce a complex metabolic syndrome: they impair nutrient absorption, trigger systemic inflammation and drive cancer cachexia, all of which lead to rapid, unintentional weight loss. In fact, over 90% of individuals with advanced pancreatic cancer experience substantial weight loss, on average losing 10–15% of their pre-illness body weight, well before diagnosis.
Although obesity increases the risk of developing pancreatic cancer, most individuals with the disease actually present with unintentional weight loss once the tumour is established. This weight loss arises from three interrelated processes:8
Together, these mechanisms make unintentional weight loss one of the most consistent early signs of advanced pancreatic cancer.
Thus, pancreatic cancers release inflammatory compounds called cytokines into the blood, causing the body to burn calories faster than they are replaced, resulting in weight loss. Weight loss and malnutrition can negatively impact your quality of life, daily functioning, response to treatment, lengthen hospital stays, and increase the risk of complications. An appropriate balance of nutrients and treatments, such as pancreatic enzyme replacement therapy, where enzymes are provided as medications to absorb fats and proteins, become necessary. This can result in the improvement of symptoms.8
As discussed in the previous sections, individuals with pancreatic cancer experience weight loss as the cancer uses more energy from the body. The problem is exacerbated by nausea and vomiting caused by the treatment, making eating harder. Furthermore, cancer can reduce the amount of enzymes the pancreas produces and sometimes blocks the enzymes from getting to the small intestine.
When the pancreas does not produce enough digestive fluid to aid nutrient absorption, the body lacks further energy, and sufficient digestion may not happen if the small intestine does not receive these enzymes. An example of this is when cancer obstructs the pancreatic duct, which carries the enzymes from the pancreas to the duodenum. In such cases, the food does not get digested, which leads to malabsorption.
Abdominal pain is another symptom associated with pancreatic cancer. The pain or discomfort can be caused by the growth of a tumour and can start to affect the nerves and organs close to the pancreas. Individuals with pancreatic cancer often feel the pain above the belly button and below the breast area. Previous cases indicate that individuals presenting with stomach pain along with other symptoms have been diagnosed with pancreatic cancer. However, abdominal pain is not the sole indicator for a pancreatic cancer diagnosis. Appropriate tests are needed to confirm the diagnosis.
The pancreas produces hormones such as insulin and glucagon to maintain normal blood glucose levels. Pancreatic tumours can impair the production of these essential hormones, leading to secondary (type 3c) diabetes mellitus.9 Unlike type 1 diabetes (autoimmune β-cell destruction) and type 2 diabetes (insulin resistance), type 3c diabetes arises from exocrine pancreatic disease.9 It remains unclear whether diabetes predisposes individuals to pancreatic cancer or whether pancreatic cancer induces diabetes. Individuals with type 3c diabetes commonly present with:
A comprehensive approach to nutrition in pancreatic cancer focuses on preventing excessive weight loss, maintaining adequate hydration and calorie intake, and managing treatment-related side effects. Be prepared to adjust diet or enzyme supplementation for diarrhoea, constipation, or bloating, and work closely with your care team to manage these symptoms effectively.10,11
Weight loss is normal for people with pancreatic cancer, but excessive weight loss can make it difficult for you to tolerate treatment. Checking your weight weekly helps to track the amount of weight lost. It is important to notify any drastic change, and consulting a dietitian is advised when you are losing 0.5-1 kg in a week.
Staying hydrated is also important, as this will prevent dehydration. The aim should be two litres of water a day. Caffeine and alcohol cause dehydration, so it is best to avoid those when monitoring your hydration. High-calorie beverages can be an alternate option.
Small and frequent meals will ensure that the body always has sufficient food to tolerate the treatment.10,11
Protein-rich foods are good for the immune system, which helps the body to recover from illness. Lean proteins are also easy to digest. Examples of protein-rich foods include eggs, boiled chicken, low-fat milk, beans, and protein bars.
You may experience digestive issues. In such cases, liquids are easier to digest. When you experience nausea and vomiting, your appetite can be very low. Hence, liquid nutrition is a better option.
Whole grains are rich in energy. This will help to increase calorie intake.
Fruits and vegetables are high in antioxidants, which are good for individuals with cancer. Eating at least five servings per day is recommended.
Healthy fats, such as olive oil, avocados, nuts, and fatty fish, provide a good source of energy.
Individuals often experience problems managing glucose levels, and high-sugar foods might shoot glucose levels up.
Treatments can cause changes in bowel habits, including diarrhoea, constipation, and bloating. Individuals may need to adjust their diet or medications to manage these symptoms.
Weight loss is a common symptom in pancreatic cancer, resulting from both tumour-related metabolic changes and treatment side effects such as surgery, chemotherapy, or radiotherapy. Tumour-induced anorexia, malabsorption (due to exocrine insufficiency), and cancer cachexia lead to progressive loss of fat and muscle mass despite adequate or even increased caloric intake. Treatment-related nausea, vomiting, and early satiety further reduce food intake, compounding weight loss and weakening individuals. Excessive weight loss impairs physical strength and reduces the ability to tolerate and recover from anticancer therapies, correlating with poorer outcomes. Nutritional and lifestyle modifications, including high-calorie, high-protein diets; pancreatic enzyme replacement; and tailored exercise, are critical to support energy balance and muscle mass. Regular weight monitoring by the multidisciplinary oncology care team (including dietitians and nutritionists) during treatment enables early identification of concerning trends and timely intervention.
