Oprah Winfrey recently flaunted her svelte figure in Idaho after attending a conference, showcasing her incredible weight loss transformation in a chic belted ensemble, RadarOnline.com has learned. The media mogul was spotted out and about earlier this week in her white monochromatic outfit consisting of a long-sleeved top, high-waisted cargo pants and sneakers, sporting an over-the-shoulder purse and sunglasses as she chatted with news correspondent Van Jones and longtime pal Gayle King. Winfrey was in good spirits while leaving the Allen & Company Sun Valley event, smiling from ear to ear as…