“This is what we look like on Day 1 of taking beetroot every day. This is Day 50.” They look like the kind of wellness influencers you see every day on social media. “This is Day 77, girl.” But none of them are real. They are A.I.- generated and designed to sell health supplements on social media. The Times reviewed hundreds of these ads to understand how A.I. video tools are helping a loosely regulated industry target American consumers and profit off of disinformation about their health. “They’re targeting us…