Being overweight or obese puts a person at greater risk for a wide variety of serious health problems. Obesity is recognized as a national problem that has grown tremendously over the last three decades, contributing to increases in medical expenditures for treatment of related diseases.

In 2018-20, 70% of residents in Lancaster County were either overweight or obese, which was higher than the state and nation (both at 67%). The counties' percentage was up 3 percentage points from 2015-17. Pennsylvania's rate increased by 1 percentage point and the U.S. rate increased by 2 percentage points during the same period.

The percentage of overweight and obese residents in Lancaster County in 2018-20 was higher than in all the comparison counties. Of the comparison counties, Chester County had the lowest percentage of overweight or obese residents at 59%. Like Lancaster, Berks/Schuylkill counties saw a decrease in the percentage of overweight and obese residents since 2015-17, down 7 percentage points while Cumberland/Perry remained unchanged during the same period. Chester County saw an increase of 3 percentage points, Dauphin/Lebanon saw an increase of 4 percentage points and York had a slight increase of 1 percentage point in the same time period.

Data come from a federal government survey designed to collect scientific data on health risks and behaviors. The data reported are for moving three-year averages. Berks and Schuylkill county data is combined by the survey and reported together. Similarly, Dauphin and Lebanon counties and Carbon, Lehigh, and Northampton counties are reported as groups of counties.

Beginning in 2011, the Centers for Disease Control made two changes to the Behavioral Risk Factor Surveillance System on which this indicator is based. The survey now includes cell-phone users, and a new statistical method is used to weight responses. As a result, changes from 2010 and years prior to 2011 and later may be a result of those technical changes rather than true trends.