BYU Study Details Concerning 10-Year Weight Gain Average Among US Adults

Larry Tucker, PhD

New data is providing an overview of contemporary trends in the obesity epidemic among adults in the United States.

An analysis of 10-year weight gain among 13,000 adults from the National Health and Nutrition Examination Survey (NHANES), results of the study indicate US adults gained an average of 17.6 pounds between their 20s and 30s, 14.3 pounds between their 30s and 40s, 9.5 pounds between their 40s and 50s, and 4.6 pounds between their 50s and 60s, with nearly 1-in-5 gaining 20% or more body weight during the 10-year study period.

“The US obesity epidemic is not slowing down,” said lead investigator Larry Tucker, PhD, a professor of exercise science at the College of Life Sciences at Brigham Young University (BYU), in a statement. “Without question, 10-year weight gain is a serious problem within the U.S. adult population.”

Although reports of obesity trends in the US, and abroad, have become commonplace, most studies have been limited by their design or dataset. Citing these limitations, Tucker and Kayla Parker, a BYU graduate student, sought to explore the current state of the obesity epidemic on a population level through a cross-sectional analysis of data from the NHANES survey. With this in mind, investigators designed their study with the intent of estimating 10-year weight gain patterns among adult patients in the US and evaluating potential associations between these patterns with key demographic variables, including age, sex, and race.

Using 2011-2018 as the period of interest, investigators identified 13,802 participants aged 36-79 years of age at baseline for inclusion in their analyses. This cohort had a mean age of 54.6±0.2 years, 52% were women, and the mean 10-year weight gain was 4.2±0.2 kg or 6.6±0.2% of initial body weight. Of the 13,802 included in the study, 1347 were between the ages of 36-39 years, 3415 were 40-49 years of age, 3425 were 50-59 years of age, 3578 were 60-69 years of age, and 2037 were 70-79 years of age.

Investigators pointed out 2019-2020 statistics were not available because of COVID-19 and the sample was limited to individuals aged 36-79 years of age to exclude the possibility of physical maturation among patients aged less than 36 years of age influencing results. Investigators also noted the use of multistage random sampling, with individual sample weights and randomly selected clusters and strata used in each statistical model, which allows results to be generalized the US adult population.

Initial analyses indicated 51% of patients experienced a weight gain of 5% or more during the study period, with 35.7% experiencing a weight gain of 10% or more and 16% experiencing a weight gain of 20% or more. In sex- and race-adjusted models, further analysis suggested age was linearly and inversely associated with 1-year weight gain in models adjusted for sex and race, whether expressed in kilograms (F=166.4; P <.0001) or percent weight gain (F=246.9; P <.0001). Investigators highlighted each 1-year increase in age was associated with a decrease in 10-year weight gain by 0.20±0.02 kg and 0.28±0.02%.

In analyses adjusted for age and race, investigators found 10-year weight gain was significantly greater (F=73.6; P <.0001) in women than in men (5.4±0.3 vs. 2.6±0.2 kg). Additionally, results indicated weight gain differed across races when expressed in kilograms (F=27.7; P <.0001) or percent weight gain (F=28.5; P <.0001), with non-Hispanic Black patients gaining more weight and non-Hispanic Asians gaining less weight than other races.

“In roughly 20 years, the prevalence of obesity increased by approximately 40% and severe obesity almost doubled,” Tucker said. “By knowing who is more likely to become obese, we can help health care providers and public health officials focus more on at-risk individuals.”

This study, “10-Year Weight Gain in 13,802 US Adults: The Role of Age, Sex, and Race,” was published in the Journal of Obesity.