Table 1.

The 5 Major Paradigms of the Obesities.

I. The Medical Paradigm: Obesity is seen as a pathological condition (ie, a disease) that requires treatment. Obesity has been recognized as a disease at least since the time of Hippocrates, but whether it is a disease remains controversial to some because not everyone who has excess adipose tissue, the hallmark of obesity, has evidence of pathology. There are no other signs or symptoms seen in all obese people other than excess fat. Physicians, though, cannot even agree on a generally accepted definition of disease or even what kind of disease obesity is. The following medical models have been proposed, and obesity has variously been called a chronic neurochemical disease, a low-grade metabolic disease (eg, hyperinsulinemia), an inflammatory disease, a disease of brown fat, a chronobiological disease, a blood-brain barrier disease, and a right brain disease.

II. The Sociocultural Paradigm: Obesity is seen within a broader social context whereby it is influenced by forces that are often external to an individual. The obese are seen as responsible for their condition as well as victims of it. The following sociocultural models have been proposed:

Crime against society model: The obese are seen as responsible for their fat condition and even seen as criminals who have misbehaved against society because society bears the consequences of their “failures of self-care”; alternatively, the obese are seen as guilty of an aesthetic crime (ie, obesity is seen as “ugly,” “disgusting,” “unsightly”).

Disability model: The obese have a voluntary, self-inflicted disability by virtue of their excess fat; they literally do not fit in society.

Religious model: The obese are seen as morally corrupt and self-indulgent; they commit the sins of gluttony and sloth, and their fat bodies are seen as “virtual confessors” of these sins.

Legal/ethical model: The obese are victims of stigma, discrimination, and prejudice whereby they are blamed for their condition and rejected and shunned by those who are not obese.

Body diversity model: The obese body is accepted and even celebrated, analogous to sexual, ethnic, or racial diversity, and not to be “pathologized”; obesity as a disease is a “flawed concept”; there is health at every size, where fitness is more important than a weight on the scale.

III. The Evolutionary Paradigm: Obesity is seen as either an appropriate or inappropriate evolutionary adaptation to the environment. Energy-conserving mechanisms, subject to strong selection (eg, so-called thrifty genotype) or neutral selection (ie, so-called drifty genotype), have evolved over centuries to weather cycles of food shortages and overt famine. The following evolutionary models have been proposed:

Energy model (laws of thermodynamics): An energy imbalance develops in the context of evolutionary forces of natural selection; the obese eat more calories than they expend, resulting in fat accumulation.

Genetic model: Although genes are not the predominant cause of obesity except in very rare cases, they may contribute substantially (50%-90%) to predisposing many to obesity in the context of excessive caloric intake; hundreds of genes may be involved, affecting, for example, how much and where fat accumulates, as well as states of satiety and hunger, and so on.

Anthropological model: Obesity is seen as a “disease of civilization” that involves evolutionary and cross-cultural factors; human obesity is seen as a “mismatch” between our adaptive biological characteristics and the modern environment.

IV. The Environmental Paradigm: Obesity is seen as resulting from the impact of environmental factors, both internal and external to the body, on the individual. These factors include changes in ambient temperature regulation with central heating and air conditioning, a 24/7 lifestyle with chronic exposure to artificial light, medications that cause weight gain, and greater availability to low-cost food and larger portions that result in failure to appreciate consumption norms. The following environmental models have been proposed:

Ecological model: Obesity is seen as a normal response to an abnormal, pathological “obesogenic” environment; the “micro” environment (eg, home, school, work) determines whether a person becomes obese, while the “macro” environment determines the prevalence of obesity in a society.

Infectious model: Adenovirus-36 has been implicated in some obesity in humans and animals, with significantly higher titers seen in some obese children and adults.

Gut bacteria model: Some obese have different percentages of gastrointestinal flora that may have an increased capacity to absorb more energy from the same quantity of food.

Epigenetic model: Obesity may result from the interaction of the internal and external environment on our DNA; the actual genetic sequence or structure is not changed but can be modified (eg, adaptively or not adaptively activating or silencing a gene) by smoke, diet, stress, infection, and so on, including in utero.

Endocrine-disrupting chemical model: Obesity may result from chronic exposure in our food and water supply (and even in breast milk) to environmental chemicals, such as brominated flame retardants, bisphenol A used in plastic bottles, and organochlorine pesticides, that may interfere with hormonal systems and circadian rhythms.

V. The Psychological/Behavioral Paradigm: Obesity is seen as the result of the mind’s cognitive, conscious behavioral choices that lead to overconsumption of food and sedentary behaviors; obesity per se is not seen as a mental disorder. The following psychological/behavioral models have been proposed:

Psychosomatic disorder model: overeating (leading to obesity) is seen as psychologically determined and a means of coping with emotional difficulties, stress, and the resultant anxiety.

Reinforcement pathology/addiction model: Overeating is seen as reflective of an excessive motivation to eat “highly reinforcing” foods and problems with impulse control; the common reward system is “hijacked,” and abnormal eating patterns develop that are analogous to addiction (eg, food-seeking behavior, persistent desire to eat despite negative consequences, failure to cut down, and even possible tolerance and dependence on food).

Self-regulation model: Obesity results from failures of self-regulation; overeating is seen as a “resistible” impulse to be differentiated from genuinely “irresistible” impulses of breathing, urinating, and sleeping; social influences on behavior are extremely powerful.