Have you been tested for Diabetes??

I'm a diabetic (type II) and ride for the diet and exercise thing---I'm on no medications right now will ride my rear end off to avoid the "needle".

If I eat a high carb lunch--I'll be tired for several hours---part of the going high with blood sugar levels.

Go get yourself checked---its easy and usually free.

If you're that overweight--its a real possibility that you are diabetic.