In the early days of the pandemic, doctors noticed something about the people severely ill from COVID-19: Many were obese. The link became more apparent as coronavirus swept across the globe and data mounted, and researchers are still trying to figure out why. Excess weight increases the chances of developing a number of health problems, including heart disease and diabetes. And those are among the conditions that can make COVID-19 patients more likely to get very sick. But there’s some evidence that obesity itself can increase the likelihood of serious complications from a coronavirus infection.