Hi guys.  I've looked at other posts and found them useful but none are specifically about what our dog is doing, so hope you can offer advice....
We have a 2 year old male Dalmatian and my partner, for some reason, bent down near him whilst feeding just before Christmas and he growled at him.  His feeding habit is routined, twice a day (dry food with water) and we make him sit and wait before we instruct him it's "OK" to eat.  You can even command him to leave halfway through and he will stop and sit down until you tell him "OK" again.
We've tried to rectify the problem by holding the bowl whilst he eats - which he does with no problem (and has done countless times in the past).  You can also touch his food whilst eating, which he's fine with.  We've also got him used to being stroked whilst eating, which again is fine now (we used to do this as a pup, but admit we've been a bit slack with this one).  The real problem he has is if you make a body movement downwards in the vicinity of him NOT the bowl.  When he growls, we've told him leave and take the bowl away for approx. 60 seconds then put it back.  The problem is I think we might be doing more harm than good as he seems to now be quite apprehensive about eating and keeps an eye on you whenever he eats and is almost expecting conflict so he's ready to growl when you get near him.  We've now stopped this to see if we can get some better ideas. 
Both me and my partner have nieces and nephews so you can imagine we want to get the dal out of this bevaviour sharpish.
Thanks guys!

Dalmatians are very bright dogs, but don't think the way we do! You're quite right - he's got it into his head that his dinner (a very precious resource) is at risk of being taken away, and of course every time that it is taken away, for however short a time, reinforces that view. In his mind he was right - you came near his dinner and it was taken away, despite him asking you not to. I'd get a bit miffed if someone took away my food every mealtime! ;)

There are several ways to 'unteach' this. One is by simply put his bowl down and again let him alone to eat - for a couple of weeks I wouldn't even be in the same room. Or you can hold his bowl at a comfortable height for him while he eats, then put it down and leave him be; but I personally wouldn't do that yet. He needs to relax and feel that his dinner is safe - that he doesn't need to guard it. This will also make him less likely to bolt his dinner quickly, which puts him at risk of bloat.

At all costs you want to avoid the situation escalating. If he finds that growling to guard his dinner doesn't protect it, it's possible he'll move on to the next stage of guarding - the snap, then the bite. As I say, they're not stupid - but they don't have human logic. He needs to relearn that humans are the givers of all Good Things, not the takers-away.

Hope this helps.

Would it not be easier to teach people, children etc that when the dog is eating, the dog is to be left in peace?

I dont want to have a go here, but this problem is one you have created. Your dog has lovely manners, will respect your command to leave in the middle of his dinner..... yet its not enough.

Just try and sit and eat a meal with someones hands in your food, petting your hair, stroking you, groping your bum.

If you DONT honestly feel like telling them to sod off and leave you alone then id be very very surprised, you would be more tolerant than I!

As JG said, leave him be now. Give him a chance to settle down and relax a bit around his food. Food is a BIG event for a dog, its not much to ask for food to happen without harrassment for 10 minutes twice a day.

NOW you do need to teach him that people near food bowls = good. Start with an EMPTY bowl. Walk by, drop in a treat.

Carry on that for a few weeks, leave him alone when he is eating food.

When hes finished his dinner, the next stage is to drop in a treat to the empty bowl. Ooh, people = food.

People must ONLY approach the food bowl to give, never to take. Even TAKING the bowl to put more in is taking in his eyes, its the taking that happens first, thats what he will react to first.

If you want him safe around kids, its kids who have to handle him. Put him on a lead, let a kid drop a treat into his bowl when hes already sure the bowl is empty.

Beyond this though, i would strongly advise leaving him in peace to eat his meals.