Obesity and body composition

In 2014, an estimated 1.9 billion adults worldwide were either overweight (BMI 25–29.9) or obese (BMI =30). The so-called obesity epidemic began in high-income, English-speaking countries in the early 1970s, but soon spread globally; more than one-third (38%) of all adults and 600,000 children under age five are overweight or obese, as are two-thirds (69%) of adults in the United States. Excessive body fat is a major cause of type 2 diabetes, hypertension, cardiovascular and liver disease, among other disorders, and has been designated a definite cause of at least fourteen cancer sites: breast (postmenopausal), colorectum, endometrium, esophagus (adenocarcinoma), gallbladder, kidney (renal cell), pancreas, gastric cardia, liver, ovary, prostate (advanced tumors), multiple myeloma, thyroid, and meningioma. Mechanisms by which adipose tissue are thought to promote tumor growth include the endocrine and metabolic effects of fat on sex hormones, growth factors, and inflammation, as well as local chemical or mechanical injury of gastrointestinal organs.