Loosing weight needs to include exercise as well as reducing the number of calories you eat. Dieting alone will not work and what she needs is a change in lifestyle not a diet otherwise when the diet comes to an end, she will simply return to her old eating habits and put the weight back on making her feel worse in the long run. My mother yo-yo diets this way constantly and it does her no good whatsoever.
One of the "tricks" I have found is to re-educate the mind that being hungry is not actually something negative (unless it is keeping me awake in the middle of the night). Drinking a glass of water when you feel hungry outside of meal times is a good way of working out if you are actually hungry or simply thirsty. If the hunger goes away, you were actually thirsty, not hungry. If it comes back very quickly, you are genuinely hungry, but this does not mean you necessarily need to actually eat - you will only loose weight if your body uses the fat reserves up instead of the food in your stomach, but your friend should also talk to her doctor and make sure that there are not underlying medical issues first.
When I need to loose weight, I don't go for the low fat option, I don't go with the cut sugars out completely, I don't go with the no chocolate whatsoever options... these don't work for me. I simply eat smaller quantities of what I like rather than stuff I don't like the taste of. (I don't need to exercise more - I already do way more than most people cycling 150-200 miles a week.)
Keeping track of her calorie intake is also quite useful - my fitness pal works to an extent. I tried it last year when I needed to track my potassium intake, but it didn't work very well for me because of a number of issues. The main issue being I cook virtually everything from scratch and this meant each and every new recipe had to be entered by hand for me. Another issue was that there would be multiple entries of the same things, but with different calorific values entered or people who can't tell the difference between sodium and salt or milligrams (mg) and grams (g) and often muddled the 2. However, if your friend eats everything pre-packed and ready made, and has a smartphone with a camera, then tracking calories would be easy for her because the myfitnesspal app has the ability to scan barcodes and enter the details for you, you simply say how many portions and for what meal it was.