We calculate the proton distribution function due to heating by subsonic, Alfvenic turbulence in a weakly magnetized collisionless plasma. The distribution function is nonthermal. For nonrelativistic energies it is an exponential of the magnitude of the proton velocity. For ultrarelativistic energies, it can be characterized as a power law with a momentum-dependent slope. We briefly discuss the implications of this work for gamma-ray emission (via pion decay) from hot accretion flows.