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.
Many people chew gum as a way to stifle cravings or prevent mindless eating but this tactic may have an unfortunate side effect: belly bloat. Everyone naturally swallows a small amount of air when they chew but it’s magnified for people who chew gum, which causes gas and bloating. In addition, some artificial sweeteners have been shown to increase your appetite for junk food, so gum could be increasing your waistline on two fronts.