Obese individuals face inconveniences: difficult walking, trouble finding clothes that fit, and difficulty fitting in bus and plane seats. What’s more, severe obesity in the 40-45 BMI range cuts life spans by eight to 10 years. In the long run, obesity can impair the immune system, thus increasing the risk of developing various diseases.
Obese people are at greater risk of developing Alzheimer’s disease, a progressive and fatal brain disease. Researchers found that obese people have 8% less brain tissue than people at healthy weights, while overweight people have 4% less brain tissue.
Being overweight or obese is a major risk factor for some cancers (endometrial, breast, and colorectal, among others). One reason obesity may raise cancer risk is because fat cells produce estrogen, which stimulates cell division. The more times cells divide, the higher the chances a random genetic error will occur, which can lead to cancer.
Obese people are about twice as likely to have type 2 diabetes as those in other weight ranges. A recent study has shed light on a possible cause of obesity leading to diabetes. Obesity is associated with increased levels of free fatty acids that stimulate the secretion of insulin via GPR40 receptors. This, in turn, contributes to the development of diseases such as diabetes.
Obesity is an major risk factor for coronary heart disease, which can lead to heart attack. Obesity raises blood cholesterol and triglyceride (a type of blood fat) levels; lowers HDL (“good” cholesterol linked with lower risk of heart disease and stroke); and raises blood pressure levels.
Carrying extra weight places extra pressure on the joints of the knees, hips, and lower back. This wears away the cartilage (the tissue that cushions joints) that normally protects them, leading to osteoarthritis.
Large-scale studies have found a link between obesity and stroke risk. Notably, in 2002, researchers reported on a study involving about 21,000 male physicians and gave a precise numerical relationship: a one-unit increase in BMI raised the risk of stroke by 6%.
Data from the U.S. Centers for Disease Control and Prevention’s National Health and Nutrition Examination Survey which involved about 4,000 children aged 2-19, indicated a link between obesity and allergy. The researchers found that obese children had higher levels of immunoglobulin E (IgE), which is an indicator of allergic activity in the body. Obese children were 26% more likely to have an allergy then children of healthy weight.