Oprah's Trainer Bob Greene Offers 6 No-Fail Tips on How to Stay Motivated With Your Fitness and Weight Loss Goals By Kathleen Doheny Reviewed by Louise Chang, MD Fitness guru Bob Greene knows staying motivated and staying in shape can be a challenge, even if you've got solid fitness and weight loss goals -- and a wildly popular television show. As Oprah's trainer, he helped her slim down and stay motivated. It paid off -- she was a svelte 160 pounds when she appeared on the cover of O, The Oprah Magazine, in January 2005. But life and a thyroid problem intervened, and she got back up to the dreaded 200-pound mark. So come January, Greene and Oprah are back to work, determined to stay motivated and drop the weight once and for all. Greene is scheduled to be the first guest Jan. 5 on "Oprah's Best Life Week" series designed to help kick-start viewers' fitness, weight loss, and other goals. The next week, Greene will be on the Oprah.com live webcasts. Also, G