I thought the same thing too because I heard that it makes them constipated. I looked for hours and I couldn't find anything that says it isn't good for them. Jack hasn't been constipated yet. I don't feed Jack table scraps while we are eating. What I do is buy fat free low calorie string cheese and cut into little round pieces (on the thinner side) then I cut those round pieces into quarters. They are bite sized and we have not had any problems with him begging for food while we are eating. Otherwise, you can always try to find treats that are small that that he may like and keep them as something special. We use Lil Bil Little Jacs for other training. They are soft and are chicken liver flavor.
I need to get Jack to training class so I need to get going. Good luck and keep us posted with his progress.