What factor is most likely to lead to increased calorie intake?

The size of bagels increases is a factor most likely to lead to increased calorie intake because larger food portions generally contain more calories. When the size of a single serving increases, it naturally results in greater overall consumption of calories if a person eats the entire larger item. This can lead to a higher total caloric intake compared to smaller portions.

Portion size has a significant influence on dietary habits. Research has shown that as portion sizes increase, people tend to eat more, often without being fully aware of the additional calories consumed. Therefore, when bagels or any other food item become larger, individuals may not adjust their eating habits accordingly, leading to an increase in overall calorie consumption.

The other options, while they might have some influence on calorie intake, do not directly correlate with an immediate increase in consumption volume as does the size of a food item.