**4. Conclusions**

In free-living humans living in an obesogenic environment, there is little evidence in support of an upper limit set point around which body weight is regulated in a homeostatic fashion. For most people, the brain's reward circuitry plays the dominant role in feeding behavior. Living in a restricted environment with periods of food deprivation, it was necessary for survival for *Homo erectus* and *Homo sapiens* to consume as much pleasant-tasting food as possible when it was available. Only recently have high-calorie foods become widely available, but the brain still responds to pleasant-tasting foods in a manner that was adaptive for the hunter-gatherers that existed in our ancestral past. After excess weight loss, relapse is high because the brain's normal response is to direct humans to overeat in the presence of an abundance of foods. For obesity interventions to be successful, long-term strategies, both individual and collective, need to better address relapse prevention, and an important component of this must include how to limit and interact with an obesogenic environment.
