People who are extremely obese, or weighing 45 kilograms more than what's deemed healthy for a person's height, die 6.5 to 13.7 years earlier than peers with a healthy weight, researchers said in an article published in PLOS Medicine. In comparison, normal-weight smokers lost an average of 8.9 years of life.
The study analyzed data from 20 similar researches of people in the United States, Sweden and Australia, which had been conducted by scientists at the U.S. National Cancer Institute.
The final sample included 9,564 extremely-obese adults and 304,001 healthy-weight adults, making it the largest-ever study of its kind.
Compared with their normal-weight peers, extremely-obese people are more likely to succumb early to heart disease, cancer and diabetes, the researchers said.
It's unclear whether losing weight would extend a person's lifespan, but not becoming obese in the first place surely will, lead investigator Cari Kitahara, a research fellow at the National Cancer Institute, told Philly.com.