Rates of obesity in the U.S. and around the world have more than doubled over the past three decades, according to a new study in The Lancet.

Why it matters: More than 1 billion people worldwide now have obesity, a sign of worsening nutrition that's also raising the risk of leading causes of death and disease such as high blood pressure, cancer and diabetes.

What they found: The global rate of obesity more than doubled among women, from 8.8% to 18.5%, and nearly tripled in men, from 4.8% to 14.0%, between 1990 and 2022, according to research that pulls from over 3,600 studies.

• The obesity rate among children and adolescents increased by roughly four times, from 1.7% to 6.9% in girls and 2.1% to 9.3% in boys.
• Just over 4 in 10 adults and 2 in 5 kids in the U.S. are obese.
• The U.S. now has the world's 10th-highest male obesity rate and 36th-highest female obesity rate. In 1990, the U.S. had the world's 17th-highest male obesity rate and the 41st-highest female obesity rate.

The big picture: Tonga and American Samoa had the highest rates of obesity among women, and American Samoa and Nauru had the highest rates of obesity among men, with more than 60% of the adult population living with obesity.

• Vietnam had the lowest female obesity rate and Ethiopia had the lowest rate among men.
• Island nations in the Pacific and the Caribbean and countries in the Middle East and North Africa had the highest combined rates of both underweight and obesity.

What they're saying: Reversing the increase in global obesity will not only require action from governments but also from the private sector, "which must be accountable for the health impacts of their products," World Health Organization director-general Tedros Adhanom Ghebreyesus said in a statement.