While it's a pretty dumb sounding initial tweet, she does go on to say:  I’m not sure which to believe/which to use in practice. Of course, it’s situational but I’ve always been taught to use calories. How do I move away from that or why should I move away from calories?  It may actually be the case that she's inundated with stupid people screaming that 'calories don't matter', and she's just trying to get clarification and solid evidence before deciding that the stupid people are stupid, which would make her not stupid. Alternately, she may truly not understand how calories work, hence the 'I've always been taught...' part, in which case she may be stupid. In any case, a calorie is just a calorie, as she should know, but where we get those calories from can influence our health and ability to limit those calories in healthful ways. Eating crap all of the time and never feeling satisfied with what you've eaten just leads to eating more crap and then finding your picture here. :)