You weigt less at the Equator because of the lower gravity

This does not seem like much, but the effects on the acceleration due to gravity are significant. On a personal note, you would weigh more at the Mid Latitudes or poles than at the equator. So if you want to lose weight, go the Equator. If you want to lose more weight, run, don’t walk!

http://www.roncuster.com/ESaM.htm