
Best thing to do is to break the habit before it forms at his age - pretty much what you're doing now, although if you could hold it yourself so you can supervise the first toilet break of the day you'll stand the best chance. Or, if he can hold it a few moments longer so you can go!
You've rightly got the idea that you don't want to make a big deal of it - and of course punishment is a huge no-no, he'd just start waiting til your back was turned. Distract then reward when he's come away, and if you aren't already, get about training a good 'leave' - or even a poo-specific cue to not eat it (I used 'no eating!' as my cue for Soli when I saw her about to do it).
Tablets can be hit and miss - never made a jot of difference to Soli, nothing did except training that cue and cleaning up regularly. They do work brilliantly for some dogs though. But, she'd already formed an almost unbreakable habit of it by the time I got her at 5yrs - she did improve but I had to manage it for the nearly 5 years I had her. So if you can stop him now, it'll be best for the long run! It can be done - Opi did it for a while at about Nando's age, I just made sure I cleared it up as soon as she did it without fuss, and it stopped as quickly as it began. Just some random puppy phase for her I think.
Another possibility if it's only his that he's eating is to add pineapple to his food - fresh works best apparently, something to do with taste.
Health-wise it's unlikely to do harm - Soli did it all her 10 years, my lab does it now out of hunger (on a diet) and my oldie does it for some unknown reason, probably nutritional and it has eased off now I've changed their food.
That's another angle - some foods make some dogs do it, so might be worth looking at that as well.