Serena Williams is championing GLP-1 drugs for weight loss after having trouble shedding pounds following the birth of her two children. The tennis legend is a paid spokesperson for Ro, which makes a version of the drugs. On Ro’s website she says she lost 31 pounds in eight months.

Serena Williams posed in a yellow swimsuit for a series of photos shared on Instagram shortly after opening up to PEOPLE exclusively about using a GLP-1 medication to help with weight loss and has since lost over 31 lbs.