Get her to focus on bodyfat not pounds. Even if she just trades 5 fat pounds for 5 muscle pounds, she'll weigh the same, but have a trimmer tighter body, because muscle is denser than fat. She should just avoid the scale and have her bodyfat tested periodically to measure progress.
For carbs, limit the simple carbs like breads/pastas, etc. and eat mostly complex carbs like oatmeal, brown rice, sweet potato, and fibrous carbs like vegatables. It helps me to cycle carbs. Higher some days, like before heavy training like leg day, and lower other days. That way I never feel deprived and it keeps my body guessing.
Eating multiple small meals a day like 5-6x helps me a lot. I feel like I have more energy and don't worry about getting hungry because I know my next meal's not far off. Each meal should include protein.
Her diet should also include some healthy fats - omega-3's like flaxseed oil, salmon, tuna. Omega-6's are good in small portions, from olive oil, avocado, nuts. Healthy fats help the body to burn fat. Drink lots of water too.