I have a bone to pick with people.

This may be a touchy subject but hear me out.

I have this friend who's a heavyset girl and she wants to lose weight. I have no qualms about this except one:

How she's doing it.

She's saying she's trying a new diet. The "diet" consists of:

• Not eating in the morning, and eating basically an apple at night 
• No lunch
• Exercising to death
• Eating in the morning, no lunch, and no dinner

I'm sorry, but it seems to me that what she's doing doesn't really constitute as a diet. In fact, it kind of worries me. You can still eat a well-portioned meal and exercise after. You can also still eat 3 meals a day and exercise. 

As I said, it kind of  worries me, and I don't know if I should be or how I should come about telling her (she's a very...sensitive person, to say the least.) Any advice?