Listen to your mum - dieting is faddish. Instead, improve the "quite" to "all" healthy and eat only nutritionally balanced, healthy foods. Cut out all sweets and junk foods, apart from an occasional treat, as humans would have always done till recent times. The exercise is important, and include plenty of stealth exercise, such as taking the stairs instead of the elevator and cycling to the shops instead of driving, etc.
Avoid Junk Food – While you are at it, make sure that you do not eat junk food by any chance. By eating junk food, you are creating your chances of getting slim, very slim. Junk food like fries and burgers and flavored sodas are the worst enemy when you are aiming to lose weight. Instead of snacking on these, you must eat nuts, and fruits when feeling hungry. https://www.youtube.com/watch?v=TyXnVTALGM0