Charlotte McKinney -- I Really Do Eat Carl's Jr, But ...

Charlotte McKinney's Super Bowl commercial for Carl's Jr. is awesome for sure ... although just about everyone is calling BS on her testimonial, because how can THAT chick eat a big fat burger?

McKinney was out Thursday at Matsuhisa in Beverly Hills (the exact opposite of Carl's Jr) where it seemed the buxom blonde had a little sake with dinner. Or a lot.

Anyway when it came time to ask if she's a fan of Carl's ... she stayed on message like a pro.

Kate Upton, you've got a real challenger to your throne.