Which of the following factors has not been directly linked to increased obesity rates?

The choice indicating the decreased availability of high-calorie foods as a factor not directly linked to increased obesity rates is correct because research generally suggests that the availability of high-calorie foods, rather than its decrease, is a significant contributor to rising obesity levels. In many contexts, the ready availability and increased marketing of calorie-dense, nutrient-poor foods have driven higher caloric consumption, leading to higher obesity rates.

In contrast, increased calorie intake has a direct relationship with obesity; as individuals consume more calories than they expend, they gain weight. Genetic predisposition plays a crucial role as well, influencing how bodies process food and store fat. Poverty levels are also closely associated with obesity, as economic constraints can lead to poor dietary choices and limited access to healthier, lower-calorie food options. These factors all converge to create environments where obesity can thrive, while the idea of decreased availability of high-calorie foods does not fit the prevailing evidence and context of rising obesity rates.