The report gave no specific reasons for the trends, not surprisingly, once the nation fights an ongoing obesity epidemic.
Mean weight, waist circumference, and body mass index (BMI) in adults have increased over the past 18 years, according to the National Center for Health Statistics report.
"A significant linear increase in body weight has been seen over time for both men and women," the report said, based on data from physical examinations in more than 47,000 people across the country over 20 years.
The average American weighs 89.8 pounds, according to the most recent year for which data are available, 2015-2016.
That's up to eight pounds from 1999-2000, when the average body weight was 189 (86 kg).
Women also accumulate pounds, going from an average of 74 kilos in 1999-2000 to 77 kilos in 2015-2016.
The average waist size of men rose from 39 to 40 inches (99 cm to 102 cm), while the female waist grew three inches – from 36 to 39 inches (92 to 98 cm) – in that period of time.
American men today are slightly shorter than two decades ago: 69.2 inches (175.6 cm) and now 69.1 inches (175.4 cm).
The average height of women also fell one-tenth of an inch since 1999, but not enough to be statistically significant.
BMI, an important health indicator that is calculated as the relationship between height and weight, showed increases in males that rose from an average of 27.8 in 1999 to 29.1 in 2015.
Women rose from 27.8 on average to 28.2.