Although Hilary Duff always looks great, she's amped up her workouts with celebrity trainer Harley Pasternak to prep for her upcoming nuptials to NHL player Mike Comrie. Pasternak, author of the 5-Factor Diet, told PeopleStyleWatch.com that "the key is to have amazing shoulders, amazing arms. Posture is really important. But it's also important to have a really tight midsection, you really want it lean and tight." So what does that entail? Ramping up her cardio, for starters. "Instead of a five-minute cardio warm-up and a five minute cardio cool-down, we extend those phases to 15 minutes," Pasternak. But diet is also key to Duff's "toned and tight look," adds Pasternak.Each day consists of small five meals: a breakfast burrito, a mid-morning snack (usually a berrie smoothie), a chopped salad for lunch, an apple cinnamon oatmeal cookie for a snack, and then usually Japanese for dinner. Duff's been working hard, and it's paid off: She showed off her figure in a green Herve Leger bandage dress at the Teen Choice Awards this week. "I'm really proud of her, she looks fantastic," Pasternak said.