Once your body adapts to the stress you put on it, it's time to change the stress. Personally, I'd only run for a long distance if I were being chased by a hungry lion, so it's unlikely you'd catch me on the treadmill. I prefer to do weight training circuits combined with calisthenics, sprints, and jumps to keep things interesting. You can mix things however you wish, as long as you find it challenging.
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.
Eat More Produce. Eating lots of low-calorie, high-volume fruits and vegetables crowds out other foods that are higher in fat and calories. Move the meat off the center of your plate and pile on the vegetables. Or try starting lunch or dinner with a vegetable salad or bowl of broth-based soup, suggests Barbara Rolls, PhD, author of The Volumetrics Eating Plan. The U.S. government's 2005 Dietary Guidelines suggest that adults get 7-13 cups of produce daily. Ward says that's not really so difficult: "Stock your kitchen with plenty of fruits and vegetables and at every meal and snack, include a few servings," she says. "Your diet will be enriched with vitamins, minerals, phytonutrients, fiber, and if you fill up on super-nutritious produce, you won't be reaching for the cookie jar."
At its core, burning fat comes down to the process of lipolysis—the breaking down of fat lipids, explains Seedman. This happens in the mitochondria of the muscles, or the powerhouses of the cells, responsible for generating the energy our cells need to do their jobs. Exercise has been shown to improve mitochondria function, which then promotes fat breakdown, Seedman adds. Plus, working out helps regulate pretty much all the hormones that optimize fat loss.