And I would probably use a rocker knife or a rolling pizza knife to facilitate better cutting with the prosthesis.
But this is really about cutting the food. I hold the fork in a similar fashion when I'm cutting my meat. The difference is that I face the fork downward and use it to spear the food.
I use a similar technique with my Adept,
If I am not using a prosthesis (I admit, that's rare! -I wear my prosthesis typically 15-18 hours per day.), I grasp the fork in the crook of my elbow (residual limb side, of course)