Kimberly "Kim" Lyons (born May 5, 1973) is an American athlete, personal trainer, nutritionist, and fitness model who has appeared on the covers of many health and fitness magazines and has also starred in the US version of the makeover-reality TV show The Biggest Loser. She originally replaced fellow trainer Jillian Michaels in season 3, but competed against her in season 4. She did not return for season 5, but may return for future seasons. She instead appeared at the 2008 Miss America pageant as a panelist, and .