I cut out meat (for sat fats) and found a healthier protein alternative (Quorn), halved my sugar intake, halved my portion sizes, and lost over thirty pounds in two years. It worked for me, and it was very safe. I'm doing it again right now, and feel great. Oh, I missed out a huge part of it: I completely cut out chocolate, desserts, and candy also.
Everyone is different. A dietitian is always the best first step, however.