Ten-year weight gain shows continued growth in US obesity rates

Research from Brigham Young University (BYU) investigators has revealed that more than half of American adults in the study gained 5% or more body weight over a ten-year period, more than a third of American adults gained 10% or more body weight and almost a fifth gained 20% or more body weight. The study, ‘10-Year Weight Gain in 13,802 US Adults: The Role of Age, Sex, and Race’, was published in the Journal of Obesity.

"The US obesity epidemic is not slowing down," said study lead author, Dr Larry Tucker, a BYU professor of exercise science. "Without question, ten-year weight gain is a serious problem within the US adult population."

Study participants were selected randomly as part of the National Health and Nutrition Examination Survey, an annual survey that examines a nationally representative sample. NHANES is a CDC-sponsored series of studies that began in the early 1960s and became a continuous program in 1999.

Using the NHANES data, the study also found that ten-year weight gain was significantly greater in women than in men, with women gaining about twice as much weight: 12lbs on average for women compared to 6lbs for men.

Weight gain also differed across races, with Black women experiencing the greatest average weight gain over the ten-year period (19.4lbs) and Asian men experiencing the least (2.9lbs).

As far as age goes, the greatest gains in weight were found in young and middle-aged adults; less weight is gained as age increases. According to the data, on average Americans gain the following weight (Table 1):

• 17.6lbs between their 20s and 30s

• 14.3lbs between their 30s and 40s

• 9.5lbs between their 40s and 50s

• 4.6lbs between their 50s and 60s

Table 1: Mean differences in 10-year weight gain across age categories in US women and men, after adjusting for the covariates

Table : 10-year weight gain is the average amount of weight gained over the previous 10 years, expressed in kg or as a percentage of initial body weight. Means on the same row with different superscript letters (a,b,c,d,e) are significantly different (p<0.05). SE represents the standard error of the mean. Means have been adjusted for differences in race for the women only and men only analyses, and sex and race when the analysis used the entire sample. The mean difference between 10-year weight gain (kg) for those in the 36–39 and 40–49 age categories, using the combined sample, was significant at the p=0.0854 level. Across the five categories of age, the sample size percentages (%) and sample size numbers (n), when combined, were 36–39 years (10.3%, n = 1347), 40–49 years (26.8%, n = 3415), 50–59 years (28.3%, n = 3425), 60–69 years (22.2%, n = 3578), and 70–79 years (12.4%, n = 2037). Because NHANES sample weights were applied to each individual, differences in the sample size of each category should be interpreted based on the percentages (%), not the raw number (n). The sample size percentages (%) can be generalized to the US adult population, but the sample numbers (n) cannot.

If adults gain the average amount of weight during each decade of adult life, they will have gained more than 45lbs, which would push many of them into the obese category. According to the Department of Health and Human Services and the CDC, 42.4% of US adults are currently living with obesity - up substantially from the 30.5% measured in 2000.

"In roughly 20 years, the prevalence of obesity increased by approximately 40% and severe obesity almost doubled," added Tucker. "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."

Further information

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