[header] How to host a weight loss contest [title] Set the dates for the competition. [step] Anywhere between 6 and 8 weeks is the shortest duration you should attempt for a weight loss challenge. Shorter challenges will have the least drastic results in the end, but they can also be the most productive because there's a slight sense of urgency throughout the competition. 
[substeps] Between 8 and 10 weeks is the most commonly used time frame for a weight loss challenge. Give the challenge a catchy name that references the duration of the event, like the " 10-week lifestyle reboot " or something else similarly motivating.