Regarding the recent increase in the obesity rate, which of the following statements is TRUE?

A) During the past 15 years, the proportion of American adults who are obese has increased from one-quarter to nearly one-third.
B) The increase in the prevalence of obesity is largely confined to North America.
C) More than one-half of American adults are obese.
D) The increase in the rate of obesity continued during the 1990s, but has leveled off in recent years.

According to the information provided in the question, the proportion of American adults who are obese has increased from one-quarter to nearly one-third during the past 15 years. Therefore, statement A is true. Statement B is false because the increase in obesity rates is not limited to North America. Statement C is also false because it states that more than half of American adults are obese, which is not supported by the information given. Statement D is false because the question does not provide evidence to suggest that obesity rates have leveled off in recent years.