Cancer And Weight

What is cancer?

Cancer is a condition in which cells in one part of the body proliferate and replicate uncontrollably. These cancerous cells can invade and damage nearby healthy tissues and organs. Cancer can develop in one part of the body before spreading to others in a process known as metastasis

Cancer cells are influenced by the environment they inhabit. Like any other cell in the human body, they depend on the host's blood for essential nutrients, hormones and growth factors. They also receive paracrine signals from neighbouring cells. These factors affect their growth and spread. These characteristics of cancer cells and the metabolic abnormalities of their host cell will affect how they survive, multiply and spread.² 

Worldwide, cancer is the second highest cause of death. However, thanks to advancements in cancer detection, treatment and prevention, survival rates are rising for many types of cancer.³ 

Cancer can cause different signs and symptoms in different parts of the body.³ The following are some general signs and symptoms of cancer:³

  • A lump or thickening on a region that can be felt beneath the skin. 
  • Skin changes, such as yellowing, darkening, or redness of the skin, sores that won't heal, or changes to moles that are already there. 
  • A persistent cough or breathing issues. 
  • Having trouble swallowing. 
  • Tiredness. 
  • A hoarse voice. 
  • Consistent indigestion or discomfort after eating. 
  • Changes in weight, including weight gain or loss. 
  • Persistent discomfort in the joints or muscles. 
  • Fevers or night sweats. 
  • Changes in bowel or bladder habits. 
  • Unexpected bruising or bleeding.

Why is obesity a cancer risk factor?

Obesity is a condition characterized by an abnormal amount and/or distribution of body fat. Those who are overweight or obese have a higher chance of developing various diseases, such as diabetes, high blood pressure, cardiovascular disease, stroke, and at least 13 different forms of cancer, as well as a higher risk of dying from any reason, when compared to people who are of a healthy weight.⁴

More than 684,000 cases of cancer linked to obesity are diagnosed in the United States each year; this includes more than 210,000 cases diagnosed in males and more than 470,000 cases diagnosed in women.⁵

A weight that is higher than what is thought to be a healthy weight for a given height is called overweight or obesity.⁵ The body mass index (BMI) is a method for determining weight and obesity. When it comes to adults, being overweight is defined as having a BMI of 25.0 to 29.9. An individual is considered obese if they have a body mass index (BMI) of 30.0 or greater.⁵ 

There are other risk factors that can potentially contribute to the development of cancer. These risk factors include hormonal imbalances, gene alterations (also known as mutations), persistent infections and the use of nicotine and alcohol. Not everyone who is obese or has a lot of extra weight will definitely get cancer. However, it does suggest that they have a higher risk of developing cancer than if they maintained a healthy weight.⁵

There is a correlation between having a higher body mass index at the time of cancer diagnosis and having a higher chance of acquiring secondary cancer that is not related to first cancer (a second primary cancer).⁴

Obesity is a pro-inflammatory state

Chronic inflammation is a major characteristic of obesity, which can contribute to many of its consequences. Obesity-induced inflammation provides additional cancer risk beyond what obesity would normally confer.  Chronic inflammation is a well-known mediator of cancer.⁶ 

Chronic inflammatory diseases like gallstones or non-alcoholic fatty liver disease are frequently seen in people who are obese. These circumstances can result in oxidative stress, which damages DNA and raises the risk of developing biliary tract cancers as well as other types of cancer.⁶

Adipose tissue produces extra oestrogen

High levels of estrogen have been linked to elevated risks of several cancers, including breast cancer, endometrial cancer, and ovarian cancer, amongst others. Adipose tissue, which is another name for fat tissue, is responsible for producing an excessive quantity of oestrogen .⁴

Obesity often leads to high levels of IGF-1

It is common for obese people to have elevated amounts of insulin and insulin-like growth factor-1 in their blood (IGF-1). Hyperinsulinemia is a disease that develops as a result of insulin resistance. It comes before the onset of type 2 diabetes, another component associated with an increased risk of cancer. Cancers of the colon, kidney, prostate and endometrium may be more likely to develop when there is an excess of insulin and IGF-1 in the body.⁴

How Can I Lower My Risk?

By adopting a healthier way of living, you can bring your weight down to a healthy range. You can lower your chance of developing cancer that is associated with obesity by adopting a healthy eating plan and engaging in regular physical activity.⁵


People who are overweight or obese should be encouraged and supported if they attempt to lose weight, even if there is still much we don't know about the connection between weight loss and cancer risk. Losing weight can have numerous other health benefits, including a reduced risk of developing heart disease and diabetes and the possibility of reducing the risk of developing cancer. Even a small amount of weight loss offers health benefits and is an excellent place to begin.


  1. Cancer [Internet]. nhs. uk. 2017 [cited 2022 Oct 7]. Available from:
  2. Gallagher EJ, LeRoith D. Obesity and diabetes: the increased risk of cancer and cancer-related mortality. Physiol Rev [Internet]. 2015 Jul [cited 2022 Oct 7];95(3):727–48. Available from:
  3. Cancer - Symptoms and causes [Internet]. Mayo Clinic. [cited 2022 Oct 7]. Available from:
  4. Obesity and cancer fact sheet - nci [Internet]. 2022 [cited 2022 Oct 7]. Available from:
  5. Obesity and cancer | cdc [Internet]. 2022 [cited 2022 Oct 7]. Available from:
  6. Deng T, Lyon CJ, Bergin S, Caligiuri MA, Hsueh WA. Obesity, inflammation, and cancer. Annu Rev Pathol. 2016 May 23;11:421–49.

Hana Hailu

Master's degree, Brain Science, University of Glasgow

Hana Hailu is an accomplished academic with a strong foundation in the field of brain science and pharmacology. She is currently pursuing her Master's degree in Brain Science from the prestigious University of Glasgow (2021-2022). Prior to this, Hana earned her Bachelor of Applied Science (BASc) in Applied Pharmacology from Queen Margaret University, where she studied from September 2017 to September 2021. With her deep knowledge and dedication, Hana is poised to make significant contributions to the world of neuroscience and pharmacology. presents all health information in line with our terms and conditions. It is essential to understand that the medical information available on our platform is not intended to substitute the relationship between a patient and their physician or doctor, as well as any medical guidance they offer. Always consult with a healthcare professional before making any decisions based on the information found on our website.
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