Table 2.

Presumptions about Obesity.^*

Presumption	Basis for Conjecture
Regularly eating (vs. skipping) breakfast is protective against obesity	Skipping breakfast purportedly leads to overeating later in the day
Early childhood is the period during which we learn exercise and eating habits that influence our weight throughout life	Weight-for-height indexes, eating behaviors, and preferences that are present in early childhood are correlated with those later in life
Eating more fruits and vegetables will result in weight loss or less weight gain, regardless of whether one intentionally makes any other behavioral or environmental changes	By eating more fruits and vegetables, a person presumably spontaneously eats less of other foods, and the resulting reduction in calories is greater than the increase in calories from the fruit and vegetables
Weight cycling (i.e., yo-yo dieting) is associated with increased mortality	In observational studies, mortality rates have been lower among persons with stable weight than among those with unstable weight
Snacking contributes to weight gain and obesity	Snack foods are presumed to be incompletely compensated for at subsequent meals, leading to weight gain
The built environment, in terms of sidewalk and park availability, influences obesity	Neighborhood-environment features may promote or inhibit physical activity, thereby affecting obesity

^*We define presumptions as unproved yet commonly espoused propositions. A list of articles in which these presumptions are implied is provided in the Supplementary Appendix.