How do I handle a friend making subtle putdowns?

We have been friends for many years. When we go out to dinner with our group of friends I have noticed the last two times we’ve gone out she’s made comments such as “are you even eating your food, it looks like you didn’t even touch it” which irritates me as have my meal was finished, I played it off saying “Look” everytime I took a bite, but it’s still on my mind. I don’t know what her issue is with my eating habits, the pervious time I finished my meal to which she pointed out and said “WOW I can’t believe it” I am a healthy weight, I eat lots of carbs so I don’t understand, anyone have any insight of what I should say or do? or why she’s doing this