Just a collection of links / resources I'll be using to seed some content.

Working out

How to get started working out?

If you're starting out (read: don't yet know what you're doing) then optimize for not getting injured. If you haven't done any weight lifting then you'll get results even if you start out slowly.

Optimize for likelihood of you not quitting. If you manage to stick to whatever plan you make you can always make adjustments where necessary. Risk of quitting is the #1 bottleneck.
Make sure it's enjoyable.

Personally, I think you shouldn't look for supplements until you feel you're reached a ceiling with regular workouts. Starting with a strict diet (measure everything) is a good idea if you're serious about this.

How to improve working out?

Start measuring

Articles

Romeo Stevens:

• http://lesswrong.com/lw/juc/optimal_exercise/
• http://lesswrong.com/lw/d7h/minimum_viable_workout_routine/
• Reply: http://lesswrong.com/lw/d9f/minimum_viable_workout_routine_is_dangerously/

http://www.bodybyscience.net/home.html/

Books

Tim Ferriss' "4 hour body" another vote for "Starting Strength" by Mark Rippetoe (2 recommendations) "5/3/1" by Jim Wendler. Available here: http://www.flexcart.com/members/elitefts/default.asp?pid=2976

Diet

http://www.gwern.net/intermittent-fasting
http://slatestarcodex.com/2015/01/12/the-physics-diet/
http://slatestarcodex.com/2014/03/04/book-review-the-perfect-health-diet/
http://slatestarcodex.com/2014/03/30/wheat-much-more-than-you-wanted-to-know/
http://slatestarcodex.com/2013/06/03/hasta-la-victorians-siempre/