Jessica Simpson's Weight br Loss Secrets Revealed The singer went up to 240 lbs when br she was pregnant with her daughter, Birdie. She managed to get back to her pre-baby weight in six months thanks to some help from her trainer, Harley Pasternak. The star lost 100 lbs br by changing her diet. Harley Pasternak, br to 'Us Weekly' Harley Pasternak, br to 'Us Weekly' Pasternak also revealed that Simpson br follows the principles of his 2013 book, br 'The Body Reset Diet.' She had three meals and two snacks a day with protein, fiber and healthy fat.