Obesity and the environment aims to look at the different environmental factors that researchers worldwide have determined cause and perpetuate obesity. Obesity is a condition in which a person's weight is higher than what is considered healthy for their height, and is the leading cause of preventable death worldwide. Obesity can result from several factors such as poor nutritional choices, overeating, genetics, culture, and metabolism. Many diseases and health complications are associated with obesity (e.g., Type-II diabetes, heart disease, cancer, stroke). Worldwide, the rates of obesity have nearly tripled since 1975, leading health professionals to label the condition as a modern epidemic in most parts of the world. Current (as of 2022) worldwide population estimates of obese adults near 13%; overweight adults total approximately 39%. Environmental obesogens Studies have shown that obesity has become increasingly prevalent in both people and animals (pets and laboratory animals). Proper diet and exercise is not linked to lower obesity rates or the trending toward obesity despite these being the assumed cure and preventative for obesity. According to Professor Robert H. Lustig from the University of California, San Francisco, "[E]ven those at the lower end of the body mass index (BMI) curve are gaining weight. Whatever is happening is happening to everyone, suggesting an environmental trigger." The theory of environmental obesogens proposes a different causal facet to obesity – that lifetime exposure to xenobiotic chemical obesogens, molecules that do not properly regulate lipid metabolism in the body and may cause obesity, changes the body's metabolic system. Data is scarce, but some in-vitro studies have found this model could be an accurate predictor of future obesity. A study suggested that smoking before and during pregnancy, for example, increases the risk of obesity twofold in children of school age. Many chemicals in common-use products are known or suspected to be obesogens and act as endocrine disruptors in the body. In a University at Albany, State University of New York study, organotin compounds, toxic chemicals derived from tin and hydrocarbon substituents, were found in a designer handbag, vinyl blinds, wallpaper, tile, and vacuum cleaner dust collected from 20 houses. The study linked obesity to phthalates, present in many PVC items, in addition to scented items like fresheners, laundry products, and personal care products. Also linked is Bisphenol A (BPA), a known environmental obesogen that reduces the body's overall number of fat cells but which makes remaining fat cells