Mollie is a funny dog she really doesn't like walking very far, 10-15 minutes and she is over it and wants to go home, But give her a ball and she will fetch for hours !

Duncan is the opposite give him a ball and he is just uninterested but he will walk and sniff and mark territory for a couple of hours easily.

Well I guess depends on the breed / dog. My dogs wouldn't fetch for 5 minutes let alone an hour!!! its not a setter thing. they'll do in the garden for a few goes but out on a walk - forget it!

So it would be a hours walk for my guys - no contest. Quartering round the fields in and out of the bushes - much more fun for them than chasing a ball that I threw and they bought back only for me to through again! Those with setters will understand!

I know what you mean Rach, even Codee the Pointer won't do the fetching on a walk, she wants to be in and out of the undergrowth, chasing birds and squirrels, pointing etc... You throw a ball for the setters, they watch it, look at you as if to say "And????"

I would agree with a mix. It's always a good idea to warm your dog up before playing fetch too - if you have to walk to a park or field to play fetch then this should do, but if you're lucky enough like me to have a field on your doorstep, or you drive to your walking location, do remember to let the dog have a walk around to warm up their muscles before they start running around. I tend to potter around the field initially, the dogs sniff around and then I throw their ball/toy short distances before I build up to throwing it further.
Kiki loves fetch and would play it all day if I let her but I am aware of joint problems, especially in her two breeds, so I do mix it up a bit - sometimes we'll have a potter around the field and a good game of fetch, sometimes we'll play a little fetch then head around the other fields where she gets to have a good sniff of where all the rabbits have been sitting (part of the pottering around is so that the rabbits hear we're on our way and head off sharpish, otherwise Kiki would spend all day chasing them!), sometimes I'll walk them into town for a change but I don't like to do too much pavement pounding with them. And now the weather is cooler, I can drive a bit further afield without worrying about the car being too hot, so we've got to new places and on group walks which gives them a change (they amuse themselves of group walks, I never take a toy along as you can sometimes get possessive issues, but to be honest they don't need toys as the other dogs are entertaining enough)
If you want the dog to lose weight then I would just up the walking length slowly and perhaps gradually move to tougher terrain - e.g. if you walk on flat lands, try to find a place with slightly more hill-y areas, don't push the dog too far at once but it'll wear it out a bit more than a flat walk

I think it depends even more on teh dog than the breed. I have a dog who's a mix of Border collie and a retriever. She has almost no interest in fetch.

Our walks are a mix of walking, playing tug, and stopping for belly rubs, as those are what she likes the most.

I would say fetch.

For Flynn, fetch is part of his work and something he absolutely adores but I wouldnt play a simple game of fetch solidly for an hour. My game of fetch sometimes lasts 1.5 hours but it's a more complicated game than simply throwing something and him bringing it back. This kind of thing tires him out far more than a lead walk ever could.

I usually walk with a wanger in my hand and chuck the ball a couple of times about every 5 minutes. The rest of the time Ollie is stalking me, waiting for me to change my grip on the wanger from "carrying grip" to "wanging grip". He would happily fetch the ball until he collapsed and walks beside me inhaling tennis ball fumes, just waiting, waiting.....

I Would get arrested if i did that

Haha...

We are very broad minded here.