Human Nutritional Evolution

Binge eating and psychostimulant addiction

Many of the various factors, characteristics, and variables involved in the addictive process can determine an individual’s vulnerability to develop drug addiction. Hedonic eating, based on pleasure rather than energy needs, modulates the same reward circuits, as do drugs of abuse. According to the last report of the World Health Organization, the worldwide obesity rate has more than doubled since 1980, reaching especially critical levels in children and young people, who are overexposed to high-fat, high-sugar, energy-dense foods. Over the past few decades, there has been an increase in the number of studies focused on how eating disorders can lead to the development of drug addiction and on the comorbidity that exists between the two disorders. Herein, we review the most recent research on the subject, focusing especially on animal models of binge eating disorders and drug addiction. The complex profile of patients with substance use and binge eating disorders requires an integrated response to dually diagnosed patients. Nutritional patterns should be considered an important variable in the treatment of substance use disorders, and future studies need to focus on specific treatments and interventions in individuals who show a special vulnerability to shift from one addiction to the other.

Measuring Human Water Needs

Water connects the environment, culture, and biology, yet only recently has it emerged as a major focus for research in human biology. To facilitate such research, we describe methods to measure biological, environmental, and perceptual indicators of human water needs. This toolkit provides an overview of methods for assessing different dimensions of human water need, both well‐established and newly‐developed. These include: (a) markers of hydration (eg, urine specific gravity, doubly labeled water) important for measuring the impacts of water need on human biological functioning; (b) methods for measuring water quality (eg, digital colorimeter, membrane filtration) essential for understanding the health risks associated with exposure to microbiological, organic, metal, inorganic nonmental, and other contaminants; and (c) assessments of household water insecurity status that track aspects of unmet water needs (eg, inadequate water service, unaffordability, and experiences of water insecurity) that are directly relevant to human health and biology. Together, these methods can advance new research about the role of water in human biology and health, including the ways that insufficient, unsafe, or insecure water produces negative biological and health outcomes.

Seeing overweight adults as babies: Physical cues and implications for stigmatization

Human babies not only are reliable triggers of tender feelings and protective tendencies, they also happen to be exceptionally fat compared to the newborns of most other species. These two facts are used to formulate a hypothesis predicting that overweight males, due to their great physical resemblance to babies, not only are perceived as cute, but also are associated with negatively evaluated traits (e.g., immaturity, lack of willpower) that are saliently inconsistent with traits required for adults. In this study, a great many physical features of adult males varying widely in weight were measured and correlated with subjective judgements. Providing preliminary support for the hypothesis, it was found that the features that were correlated with objective and perceived fatness (e.g., circularity of body parts, relatively large head, short and thick neck) also correlated with perceived babyishness. Perceived fatness and babyishness had curvilinear influences on the positive and prosocial appraisal of cuteness, but were primarily negatively related to perceived willpower and beauty. Results are used to formulate an alternative evolutionary perspective on social responses to overweight and obese individuals, emphasizing the uniquely human adaptive value of fatness and the misfiring of the underlying response mechanism under modern conditions of living.