Social media commentators noted that Kennedy appeared the least enthusiastic of the diners as he gingerly held an opened burger box, with fries and a bottle of Coca-Cola in front of him.
The 70-year-old, a conspiracy theorist and anti-vaccine campaigner, has long argued that the United States needs to curb its obesity epidemic by reducing the high levels of sugar, fat and high-additive processed food in the national diet.
In a podcast posted last week, he was scathing about Trump’s diet, saying “the stuff that he eats is really bad”.
“Campaign food is always bad, but the food that goes onto (Trump’s) airplane is just poison,” he told the Joe Polish podcast. “You don’t have a choice, you’re either given KFC or Big Macs.”
Trump has never made a secret of his love of fast food and Diet Coke, even briefly stopping to work at a McDonald’s in Pennsylvania during his campaign in October.
“I love salt!” he told workers there.
Kennedy will need confirmation by the Senate to take up his job as health secretary, with some senior Republicans voicing concerns about his suitability for the position.