Two years ago, when Los Angeles' Louis DeMenthon was trying to bulk up, he encountered the ubiquitous challenge faced by those seeking physique changes: meal planning.

In vain, DeMenthon searched for an online planner that would tell him exactly what foods to eat in order to pack on muscle. When he came up empty-handed, DeMenthon says, "I decided I would just create it myself."

The 23-year-old recently launched Eat This Much, a free meal-planning website that plays the part of a virtual nutritionist.