Health risks of adult obesity

There is now good evidence to show that adult obesity is associated with a wide range of health problems, these are summarised below.

Musculoskeletal system

  • Raised body weight puts strain on the body's joints, especially the knees, increasing the risk of osteoarthritis (degeneration of cartilage and underlying bone within a joint).
  • There is also an increased risk of low back pain.

Circulatory system

  • Raised BMI increases the risk of hypertension (high blood pressure), which is itself a risk factor for coronary heart disease and stroke and can contribute to other conditions such as renal failure.
  • The risk of coronary heart disease (including heart attacks and heart failure) and stroke are both substantially increased.
  • Risks of deep vein thrombosis and pulmonary embolism are also increased.

Metabolic and endocrine systems

  • The risk of Type 2 diabetes is substantially raised: it has been estimated that excess body fat underlies almost two-thirds of cases of diabetes in men and three quarters of cases in women. Diabetes currently affects nearly 200 million people worldwide and International Diabeted Federation predict that this will increase to over 330 million by 2025, with a massive burden in developing countries. Worldwide, the number of people with diabetes has tripled since 1985.
  • There is a greater risk of dyslipidemia (for example, high total cholesterol or high levels of triglycerides), which also contributes to the risk of circulatory disease by speeding up atherosclerosis (fatty changes to the linings of the arteries).
  • Metabolic syndrome is a combination of disorders including high blood glucose, high blood pressure and high cholesterol and triglyderide levels. It is more common in obese individuals and is associated with significant risks of coronary heart disease and Type 2 diabetes.


  • The risk of several cancers is higher in obese people, including endometrial, breast and colon cancers.

Reproductive and urological problems

  • Obesity is associated with greater risk of stress incontinence in women.
  • Obese women are at greater risk of menstrual abnormalities, polycystic ovarian syndrome and infertility.
  • Obese men are at higher risk of erectile dysfunction.
  • Maternal obesity is associated with health risks for both the mother and the child during and after pregnancy. Click here for more information on maternal obesity

Respiratory problems

  • Overweight and obese people are at increased risk of sleep apnoea (interruptions to breathing while asleep) and other respiratory problems such as asthma.

Non-alcoholic fatty liver disease

  • The term ‘non-alcoholic fatty liver disease’ (NAFLD) refers to a range of conditions resulting from the accumulation of fat in cells inside the liver. It is one of the commonest forms of liver disease in the UK. If left untreated, it may progress to severe forms such as non-alcoholic steatohepatitis (NASH), fibrosis and cirrhosis. It has also been linked to liver cancer.
  • Obesity is an important risk factor for the condition: over 66% of overweight people, and over 90% of obese individuals are at risk of NAFLD [Argo CK, Caldwell SH. Epidemiology and natural history of non-alcoholic steatohepatitis. Clin Liver Dis 2009; 13: 511-531]. As levels of obesity have risen, so has the prevalence of NAFLD.
  • There is a lack of high quality data related to the prevalence of NAFLD in the UK. This is due to a number of factors including variations in diagnostic criteria, the invasive nature of diagnosis, and the lack of symptoms in people with mild forms of the condition.
  • Approaches to tackling the condition focus on weight reduction through a combination of diet and physical activity, but there is no specific evidence-based treatment for NAFLD.
  • Scientific understanding of the condition is limited, and there is a lack of high quality data on it. The impact of rising obesity levels on the prevalence and severity of NAFLD is not known, nor are the natural history or optimal management of the condition. There is a lack of scientific consensus on just how significant a threat to health NAFLD presents. In order to explore these issues in more detail we held an initial expert workshop in October 2013, and are continuing to develop this work in PHE and with external partners.
  • Improvements in outcomes from NAFLD will require better data collection through primary and secondary care, death certification, and transplant registers, as well as research into the causes and treatment of the condition.

Gastrointestinal disease

Obesity is associated with:

  • Increased risk of gastro-oesophageal reflux
  • Increased risk of gall stones

Psychological and social problems

  • Overweight and obese people may suffer from stress, low self-esteem, social disadvantage, depression and reduced libido.

Click here for more information on adult obesity

Further reading

Al Lawati NM, Patel SR and Ayas NT (2009). Epidemiology, risk factors and consequences of obstructve sleep apnea and short sleep duration. Progress in Cardiovascular Diseases. 51(4): 285-293

Bray GA (2004). Medical Consequences of Obesity. (date). Journal of Clinical Endocrinology and Metabolism. 89(6): 2583-2589

Felson DT, Lawrence RC, Dieppe PA et al (2000). Osteoarthritis: new insights. Part 1: the disease and its risk factors. Annals of Internal Medicine. 133(8): 635-646

McTiernan A (2000). Associations between energy balance and body mass index and risk of breast carcinoma in women from diverse racial and ethnic backgrounds in the US. Cancer. 88(5 suppl): 1248-1255

Mydlo JH (2004) The impact of obesity in urology. Urologic Clinics of North America. 31(2): 275-287

Pi-Sunyer X (2009). The medical risks of obesity. Postgraduate Medicine. 121(6): 21-33.

Poirier P, Giles TD, Bray GA et al (2006). Obesity and cardiovascular disease: pathophysiology, evaulation and effect of weight loss: an update of the 1997 American Heart association Scientific Statement on Obesity and Heart Disease. Circulation. 113(6): 898-918

Runge CF (2007) Economic consequences of the obese. Diabetes. 56(11): 2668-2672

Stein CJ and Colditz GA (2004). The epidemic of obesity. Journal of Clinical Endocrinology and Metabolism. 89(6): 2522-2525

Wyatt SB, Winters KP and Dubbert PM (2006). Overweight and obesity: prevalence, consequences and causes of a growing public health problem. American Journal of the Medical Sciences. 331(4): 166-174

International Diabetes Taskforce website:

Foresight Report website: