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. , worldwide population estimates of obese adults are 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 larger. Additionally, glucose intolerance and more abdominal fat were found to be the results of obesogens in animals and the long-term effects of low-birth weight babies. The study strongly indicates that obesogens change an individual's metabolic set points for gaining weight.
Research on obesogens indicate some endocrine disrupting chemicals (EDCs) belong to this class of compounds. Bruce Blumberg, a professor of developmental and cell biology at UC Irvine, has found compelling evidence that exposure to the chemical Tributyltin (TBT), a compound used in pesticides, can trigger fat cell creation.
As several cases have confirmed, farm workers in America have unwillingly or unknowingly worked in fields that had been recently sprayed with TBT and other dangerous chemicals. Among a wide variety of health risks, farm workers may bear a disproportionate risk of exposure to such obesogens. While legislation has been enacted to require a minimum amount of time to pass before workers enter sprayed fields, the lack of legal and political power of many farm workers combined with the fact that enforcing such laws can be difficult, makes exposure to obesogens a possible threat to the livelihood of many farm workers.
Location
Obesity by country The country to country rates of obese adults in a total population vary due to different environments, lifestyles, and diets. While there is no direct correlation between obesity rates and economic status, wealthier countries have more resources to utilize for health and fitness awareness. According to World Population Review, in 2022 all of the top ten countries with the highest percentage of obese adults are found in the South Pacific. Several theories attempt to explain this fact, including the popularity of unhealthy fast food, the use of frying as a means to prepare food, and possible genetic predispositions. In contrast, the country with the lowest percentage of total obese adults is Vietnam, with only 2.1%, attributed to chronic food insecurity and child malnutrition. +Highest Number of Obese Adults by CountryObese Adults in Population (%)Nauru61Cook Islands 55.9Palau55.3Marshall Islands52.9Tuvalu51.6Niue50Tonga48.2Samoa47.3Kiribati46Micronesia45.8 In the United States, the prevalence of obese adults in the mid-1990's was substantially lower than current figures. In 1994, the prevalence of obesity in every state was less than 22%, but by 2000, 11 states (Alabama, Arkansas, Kentucky, Louisiana, Michigan, Mississippi, Missouri, South Carolina, Tennessee, Texas, and West Virginia) had surpassed that figure. Six states had a population percentage of obese adults of more than 30%; the remaining states ranged between 20% and 30%. By 2015, no state had a prevalence of obesity under 18%; almost all states exceeded 22%, and six states exceeded 26%. According to the Centers for Disease Control and Prevention (CDC), in 2016 the number of obese people in the United States reached an all-time high of about 93 million, up 33% from 2008. By 2020, the U.S, obesity prevalence was 41.9%, an increase from 30.5% in 2017 to 41.9% in 2020. During the same time, the prevalence of severe obesity increased from 4.7% to 9.2%.
Race
Race and genetics
Race and genetics are two other dimensions of obesity that have been extensively studied. Some researchers have found that genetics increase the likelihood of occurrence of obesity through higher levels of fat deposition and adipokine secretion. Other critics suggest that race itself may affect the way obesity presents itself in individuals. In a recent study of 70,000 men and women of African ancestry, researchers found three new common genetic variants. These single-nucleotide polymorphisms (SNPs) are connected to body mass index (BMI) and obesity. Therefore, individuals who carry these variants are more at risk of becoming obese. Researchers noted that these genetic variants are very small determinants in most cases of obesity. Most medical professionals agree that environmental factors, poor health, and eating habits are still considered to be the strongest contributors of obesity.
One study found that Black men and women have a lower percentage of body fat than White men and women with the same body mass index (BMI). A similar study concluded that obese Black adolescents had significantly less dangerous visceral fat than obese White adolescents. This finding is significant because visceral fat has been more strongly linked to the risk of disease compared to fat stored in other parts of the body.
Between 1980 and 2000, obesity rates in the United States doubled among young children and tripled among teens. Numerous studies aimed to provide insight into genetic, economic, and/or environmental causes of obesity. According to the "thrifty gene hypothesis, a genetic theory explaining rising obesity rates, certain individuals are genetically predisposed to metabolize food more efficiently than others as a result of human evolution. In times of scarcity, these genes were essential in ensuring survival; in times of abundance, these same genes cause obesity. In first-world countries like the United States, the UK, Australia, and most Western European countries, evolution has led to an increased sedentary lifestyle and high rates of sugar and fat consumption, directly leading to obesity.
Race and food deserts According to the CDC, studies show that members of racial and ethnic minority communities are disproportionately obese. Hispanics (47%) and non-Hispanic Blacks (46.8%) had the highest age-adjusted prevalence of obesity compared to non-Hispanic Whites (37.9%) and non-Hispanic Asians (12.7%). A similar study in the American Journal of Public Health found a strong correlation between community demographics and the likelihood of obesity: Hispanics (28.7%) and non-Hispanic Blacks (36.1%) evidenced higher percentages of obesity than non-Hispanic Whites (24.5%) and non-Hispanic Asians (7.1%). Many theories exist to explain these disparities, including differing dietary behaviors among ethnic groups, differing cultural norms in regards to body weight and size, and unequal access to healthy foods. Due to economic factors, many Hispanics and non-Hispanic Blacks rely on cheap calories with little nutritional value. According to television broadcast statistics, Hispanic and Black teens and children are specifically targeted by fast food restaurants. Spanish-language TV advertisement has increased by 8%, and restaurants such as KFC and Burger King have increased their spending on Spanish advertisements from 35% to 41% while decreasing English-language advertising.
The Department of Agriculture defines food deserts as neighborhoods without ready access to fresh, healthy, and affordable food. Communities suffering in food deserts are more likely to be Hispanic and Black neighborhoods, limiting available healthy food options. In 2015, Chicago's Mayor Emmanuel partnered with Growing Power, which transported affordable fresh fruits and vegetables to food desert areas. In 2004, Pennsylvania enacted a $100 million economic stimulus package that subsidized grocery stores by offering a low-cost business loan from the Fresh Food Financing Initiative (FFFI) if they were located in a food desert. In 2008, former New York City Mayor Bloomberg introduced the Green Cart amendment, which allowed pushcart vendors to receive a low-cost permit if they were willing to operate in under-served neighborhoods. The Green Cart program projected an improvement in the health of 75,000 New Yorkers, and save at least 50 lives a year over the long term.
Hispanic and Black communities frequently have less access to exercise and fitness opportunities (i.e., public parks) as well as healthy green spaces which creates a obesogenic environment. Low income neighborhoods are burdened with an abundance of fast food outlets. A 2005 study conducted in Chicago found that Black neighborhoods had 14 fast food restaurants per 100,000 neighborhood residents, while White neighborhoods had 9.4 fast food restaurants per 100,000 residents. Fast food restaurants offer inexpensive, calorie-dense food that is nutrient-poor and unhealthy with high levels of sugar, fat, and sodium. According to the USDA recommendation for daily caloric intake, a McDonald's meal has more than half a day's worth of calories. In the short term, the residents of these communities are making an economically rational decision when purchasing fast food as it is easily accessible and inexpensive. The alternative would be purchasing low quality groceries at a high cost. In the long-term, however, studies show that the consumption of fast food hurts overall health, raising the probability of becoming obese.
Economic status of individuals in ethnic groups does not fully explain the disparity between communities. A 2009 study in the Journal of Epidemiology and Community Health found that racial/ethnic minorities have a higher risk of being obese within each observed socioeconomic group, suggesting that race is a key indicator in determining disparities of obesity risk. The study also implies that structural racism may cause certain racial/ethnic groups to experience a disproportionate risk of obesity.
Social perspective
Weight bias and stigma