For about 2 weeks my dd has been bringing her packed lunch home with most of it uneaten - I haven't commented beyond the fact if trying to find out what she would prefer to eat. However today she has come back with nothing bar a banana eaten. She has been at gym training all day and there is no way she can keep up the level of exercise on so little food.
I asked her direct and she says its cos she is scared of getting fat!
Apparently they have been doing healthy eating in school and she has decided she shouldn't be eating any fats and very little carbohydrates 
I explained that our bodies need to have fuel to work properly and what is a good healthy diet. She has gone off to bed in tears saying I don't understand!
Wtf do I do now? We eat healthily, we all have an active lifestyle doing sports, outside activities and body weight has never been discussed. ( I like my food too much to have issues with dieting hence the exercise)
How do I deal with this?