As my puppy gets older I'm finding it harder to get engagement with food. He's gotten to the point where he's not even interested in steak. Do you have any advice?

Thanks for taking the time to read this email. Your previous responses to my questions have really helped. I just finished placing my order for some training videos; retrieve, tug, puppy bite work, and some equipment.

I have a question regarding engagement. I have been training my dog with Michael Ellis' The Power of Training Dogs with Food. It has been a few months now and my pup is doing great. My problem, I have noticed, is that it is harder to keep his engagement with food. Before, I would run around and he was all over me really engaged in what we were doing. I still run around trying to keep his attention and such. Is it normal for a 6 month old puppy not to be very motivated by food? I have used all kinds of treats mostly all natural treats, all beef hot dogs, chicken, and pieces of steak. It has gotten to the point where not even the steak will really interest him. I'm really hoping that teaching him tug will reignite his obedience drive. Any advice would be helpful. Thanks again.