Sorry if this is a really stupid question but I'm really curious about feeding puppies.

I've read quite a bit, especially about raw feeding as I've changed to this for both my small pup and 9yr old, medium girl.
What I'm confused about is the different requirements for small and large breeds. 
Commercial foods have different ones for different size dogs/puppies yet in raw there is just a % of body-weight given.  Why is this?

I've also frequently read not to overfeed large breed pups as growing too quickly has an adverse effect on their development.  Why would it be different for different sizes to grow too quickly? Surely they will only grow at their appropriate rate?  Also, if amounts of food affect their growth rate, how can some puppies get fat, some small, thin, lanky, solid etc? 
If I don't feed my pup as much, will he stay smaller rather than get thinner?  If I've fed him too much (more than recommended), and he’s a good shape (waistline and ribs appropriate) how will I know I've overfed him and caused him to grow too fast?

I think I’ve got information overload and can’t sort it all out :B

Most of it to be honest is a sales thing.

Most of the foods contain minimum nutritional levels of animal based proteins filled out with carbohydrate which is cheaper.

Pups fed this would not have optimum body building nutrients (protein).  Carbs and protein calorie wise are about the same, so a pup wouldn't get any fatter or thinner, except for the fat levels in the food.

Raw food will be all species appropriate nutrients to provide both body building and energy, and the amounts eaten will determine the levels they get.

You have probably noticed that dogs fed a better quality food 9better ingredients as in animal proteins) tend to have better muscle tone and coat, that those fed on almost completely cereal based diets, which may just be adequate rather than optimum.

I've forgotten how to quote Grrgh

I've definitely seen a difference in muscle etc, (even with older girl) as you said, since feeding raw.  It makes sense about the bulking agents used in the commercial foods.  They just seem to want to scare you into buying the 'specialised' foods at 2-3 times the price!

But, what about the not overfeeding large breeds bit? {If you overfeed them they will grow too quickly, which is bad for their bones} I'm probably being really simple but, to me, if you overfeed a dog/pup it will get fat not grow too quickly, which is a warning I've read many times in many places(growing too quickly not getting fat lol).

Greedy pups can grow too quickly, but it should not be a problem with either of your dogs, which are small to medium.

I wasn't really asking for my dogs, just the general principle.  I still don't get it I'm afraid Why dogs can grow too fast rather than get fat, that is. Though I'm now getting an image of overfeeding plants that then become tall and spindly,if they're not cut back. Can't do that with dogs though lol

> Though I'm now getting an image of overfeeding plants that then become tall and spindly,

That's exactly the principle

With my breed (leonberger) you would aim at less than 2kg/week weight gain... any more and you are likely to start having issues with legs, go down on pastetns etc... as bones /ligaments can't keep up. It is partly of being fat/too heavy but also extra energy will be put towards growth. The puppy will not end up taller than what it's genes say but incorrect feeding can defiantly make them try get there quicker, bendy legs/ligaments struggling can then damage the growth plates meaning actual structural issues with sceleton. slower the puppy grows better as all parts can keep up with ...
With raw feeding they seem to be able to regulate the growth better but if one over fed on raw, would still get issues as too much weight still would cause some of the same problems as kibble feeding.  Not sure if I've actually answered your question at all thinking about it :-)

Thanks I think I'm getting there - slowly.  I've re-read Brainless' posts too, and done more googling.
If I understand it correctly with commercial foods (especially cheaper ones) there's too many empty  calories. In raw, feeding much of the calories comes from protein which doesn't have the same effect, on bones in particular. Something to do with calcium balance I think.
If a pup eats too much, (easier for a large breed as they have bigger stomach) they will put on fat that will then be converted to create the problems -you've described, Noora.
I've also read smaller dogs have greater bone density than big dogs so they are better able to support the extra, if needed.
Thanks for your replies.
Leonbergers are gorgeous.

Getting the correct ratio of meat to bone is crucial - especially in puppies. As well as the obvious problem of too much bone causing compaction  you also have to consider that adult dogs are able to excrete excess  calcium whereas puppies are not able to do so at a young age.

Thanks Harley, Yet something else I didn't know.
  I take it the 80:10:10 ratio is correct for puppies? One of the 10% being calcium.
How long would you say they are puppies for?  I've read small breeds - 10 months, medium - 12 months and large 18months. 
My pup is Jack Russell size.

Have a look at this link - scroll down to the part about calcium absorbtion and excretion

http://dogcathomeprepareddiet.com/dietrelated_skeletal_and_joint.html

That link is really informative, thanks so much for sharing it. 

There's a lot to take in, I'll have to reread it several more times.  What I think I'm beginning to grasp is:

Other than before weaning, a pup should be the same shape, or as lean as, an adult dog.  There shouldn't be 'puppy fat' after a week or two after taking a new pup home.

Overfeeding leads to fat, which leads to pup's bones growing too fast, which leads to bone damage. This is worst for large dogs but can still have negative effects on even toy breeds.

Even in raw feeding (which doesn't have the extra calories from carbs/fillers, which can lead to pups being overweight) great care needs to be taken over bone (&/or calcium) intake.  Too much calcium (can) cause/s bone abnormalities, deficiencies, weaknesses etc leading to lameness and pain.

Puppies can't get rid of excess calcium/bone as well as adults, so greater care is needed with them.

I really appreciate your help.