“Obesity affects every organ system in the body and causes negative effects on each of these systems,” says Mir Ali, MD, a bariatric surgeon and the medical director of Memorial Care Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, California. This doesn’t mean everyone diagnosed with obesity will face these complications, but it does mean their risk factors for developing them are higher than for someone who doesn’t fall into the obesity category. Dr. Ali says the conditions most commonly associated with obesity are:
DiabetesHigh blood pressureHeart diseaseSleep apneaCancer
As the CDC notes, there are several other conditions associated with obesity. Below, we’ll discuss some common complications of obesity. It’s important to note that genetics and lifestyle play a role in many of these conditions as well, so someone doesn’t have to be diagnosed with obesity to be diagnosed with one of these complications. But if obesity is considered a key factor, many of these complications can be reduced or eliminated with weight loss. People with high blood pressure can also be at risk of the following, among other issues:
Heart diseaseHeart attackStrokeKidney disease
Genetics contribute, but obesity is also associated with high blood pressure. Prior research from the Framingham Offspring Study suggested that obesity accounts for 65 to 78 percent of primary high blood pressure cases. According to the American Heart Association (AHA), people with any body size can have high cholesterol, though carrying extra body weight or having obesity can increase your likelihood of high cholesterol. The AHA also states that people who lose 5 to 10 percent of their body weight may improve their cholesterol levels. According to the American Diabetes Association, carrying excess weight increases the risk of type 2 diabetes, but losing even a small amount of weight (10 to 15 pounds, for example) can improve your health. Research also shows a link between obesity and the development of prediabetes and type 2 diabetes. The American Heart Association considers obesity to be a contributing factor in the development of heart disease. More recently, abdominal obesity, meaning excess weight around the stomach and midsection, has been shown to contribute to heart disease. Doctors may measure abdominal obesity by using an alternative weight measure to BMI, called waist circumference, according to a study published in Current Opinion in Nutrition and Metabolic Care in September 2018. The National Institute of Diabetes and Digestive Kidney Diseases (NIDDK) says losing 5 to 10 percent of your weight may reduce risk factors for heart disease. That means someone who weighs 200 pounds (lb) could lose as little as 10 lb, or 5 percent of their weight, and see a lower heart disease risk. A study published June 1, 2017, in the Lancet Public Health found that obesity more than doubled the risk of stroke. And compared with people with a normal BMI, people with a BMI suggesting severe obesity have a tenfold higher risk of stroke. A study published July 4, 2019, in BMC Gastroenterology found that obesity was a risk factor for gallstones. A study published February 27, 2020, in Scientific Reports linked obesity to osteoarthritis in the knee because of the stress placed on weight-bearing joints. Obesity may also play a role in the development of arthritis in other joints. Obesity can lead to excess fat deposits in the neck that then block the upper airway during sleep. The airway blockage can cause or worsen snoring, gasping, or snorting while sleeping. Per the CDC, untreated sleep apnea can increase the risk of:
Heart diseaseStrokeType 2 diabetesDepression
Asthma can be both a complication of obesity and an existing condition made more challenging to manage with obesity. People with obesity can have an increased risk of asthma, and those with asthma who become obese can see an increase in symptoms and symptom severity. This is true for both adults and children. An article published in the Journal of Allergy and Clinical Immunology in April 2018 estimated that almost 60 percent of U.S. adults who had severe asthma also had obesity. Obesity can cause changes to lung function when excess weight puts pressure on the lungs, limiting their capacity to take in air, as well as increasing inflammation that may worsen the condition. According to 2005–2010 data from the CDC, 43 percent of adults who had depression also had obesity. Adults with depression were also found more likely to have obesity than those without depression. While researchers believe there’s a link, more research needs to be done in order to better understand why anxiety and mood disorders are a complication of obesity. According to the National Cancer Institute, people with obesity may have a larger risk of developing at least 13 types of cancer. These include:
EndometrialEsophageal adenocarcinomaGastric cardiaLiverKidneyMultiple myelomaMeningiomaPancreaticColorectalGallbladderBreastOvarianThyroid
While more research is needed to explain exactly how obesity plays a role in the development of cancer, current theories include:
Fat tissue creates extra estrogen, which is the hormone associated with cancers such as breast, endometrial, and ovarian cancer.High levels of insulin and the development of type 2 diabetes, risk factors for some cancers, are common in people with obesity.Inflammatory conditions, such as gallstones or nonalcoholic fatty liver disease, which are often complications of obesity, can increase cancer risk.The hormones that fat cells produce can increase or block cell growth, which might promote cancer cell growth in certain cancers.
