I have a friend that is losing too much weight and is in denial. I try to help but she will not listen how can I approach her?

What is your definition of too much weight? What did she weigh before, what does she weigh now? How is she losing the weight?

She has lost about 15-20 pounds by not eating certain meals like breakfast or lunch, eating only salads, and has tried to vomit.

So she is eating better and losing weight? That a good idea. Did she tell you that she has vomited? Or do you assume this?

She told me. But she said that she will not do it again.

So she's eating good, and she made a mistake and learned from it. It doesn't sound like anything you need to be worried about. She is replacing meals with healthy food. That's a great start. Is she working out?

If she's missing major meals especially breakfast this is not a good diet! Breakfast is the most important meals because your body has been with anu nutrition throughout the night, so something as simple as yogurt or fruit, milk, and wheat toast, all low in calories would be the thing for her to do. She can cut calories by eating all the meals necessary, but try and convenience her salads are great, fruits, veggies, whole grains. But your body needs certain nutrients every day in order to stay healthy. Losing weight can be achieved even when you eat throughout the day, by eating smart, smaller portions, but include all food groups.