The phrase comes from Ronnie Coleman, the eight-time Mr Olympia whose intense training videos made Yeah Buddy and Lightweight Baby part of gym language. Clips of Coleman shouting the line while lifting enormous weights circulated among bodybuilding fans before spreading to social media edits, where creators reused it as shorthand for effortless strength. It remains popular because it is short, instantly recognisable to fitness audiences, and works as both genuine motivation and playful exaggeration when someone makes a hard task look easy.