Steve's idea is that many JMT hikers use instead of one last resupply at MTR. Depending on how many miles you're planning on per day, some just push out from MTR. Besides the climb up Forrester, the section from the Kearsarge Pass trail cut off to Guitar is pretty tame.
Also, many find a loss of appetite at elevation. If you're hiking out after the Whitney summit, shoot for the tarn about 15 minutes past Guitar Lake. A lot less people there and the water source is a creek west of the trail. Whitney was really a great experience, but honestly Forrester was breath taking. Once you're on the south side of the pass and walking on that trail, it's unbelievable. Way better than the summit of Whitney.
