Fat March is based on a British format called Too Big To Walk?, The show focused on twelve individuals walking from the starting line of the Boston Marathon, over 500 miles to Washington, D.C. for a grand prize of $1.2 million.
The show focused on teamwork by starting with the initial prize of $1.2 million, meaning each contestant will receive $100,000 upon completion. However, at the end of each episode, contestants have an opportunity to nominate any of their team for removal from the walk. Anytime someone is voted out, is physically unable to continue or chooses to stop, each remaining individual's share is cut by $10,000. Participants can choose to vote for no one. It only takes one vote for a person to be ejected; if eleven people vote for no one, but one person votes for someone, that one person who received one vote is eliminated.
- The show had received mixed reactions from fitness experts.
- The original format under the title Too Big To Walk? aired on the British television network Channel Four in 2006.