but not much impact compared to rural area
Collection of food waste for feeding pigs used to be a fairly widespread thing - restaurants would have a ‘slops bin’ into which post-customer leftovers, peelings, trimmings, unsold and expired food would all be thrown and this would be collected and fed to livestock.
I think this stopped happening when prion diseases started to be better understood and it was resolved that feeding (for example) leftover pork to pigs might not be a great idea.
There are still industries where waste streams do get diverted to animal fodder, but typically only when it’s all one kind of thing, like whey from making cheese, pomace from pressed fruit, or trimmings and misshapes from an industrial cake bakery.
And also cause famine whenever there’s a bad harvest and “just enough food” becomes “not enough food”.
I believe some restaurants still do that, but the waste is composted rather than fed to pigs.
The local trash haulers here also collect food waste from households for composting. They even distributed buckets for people to collect their food waste and then dump into the yard debris bin. I do this, although we rarely have yard debris. I don’t generate much food waste, less than one bucketful every two weeks. It still gets put out for collection in a mostly empty bin.
Yeah, I think commercial food waste here generally goes off to the biogas digesters, so it’s not exactly wasted, except in the sense that those things could run on grass clippings and hungry people could eat the food if we could solve for that.
Let them eat grass?
BTW, did one of your parents ever give you the old guilt-trip, “Finish your food; there are starving people in [whatever country or continent].” That of course never made sense; whether or not you eat what’s on your plate doesn’t affect what’s available elsewhere.
Hungry people in one place vs food being carelessly wasted in another are not necessarily causally linked, but is it decent that this happens?
Decent versus indecent?
Those being antonyms, yeah, I suppose.
Isn’t it indecent that there are people who are desperately hungry and other people who are casually tossing good food in the waste?
In theory, yes, it’s indecent that some are hungry while others waste food or overeat, but how far do you take it? Do you only eat the cheapest, most minimal amount and donate what remains of your food budget to hunger relief? Do you give up your nice residence, move to a flophouse and use the difference for housing for the poor?
You’re right - if were to say that nobody gets to eat until everybody can eat, the result would be that everybody starves, so that’s obviously no good, and taken to the extreme, if it’s bad for one person to have more than another, then when you feed one hungry person, you have elevated them to a bad position, which can’t be right.
I think maybe the best we can do is not to just accept that this is inevitable and unfixable, because that normalises it and lets us off the hook of feeling any responsibility or concern. Whilst we may never completely solve this, I feel like there probably is more we could be doing - and being offended by the imbalance is perhaps a good way to keep that fresh in mind.
I would not consider food given to animals, whether pets, zoo animals, wildlife, etc. to be wasteful. Better that than the landfill, unless something genuinely belongs there.
Definitely better than landfill, but worse than it could be - since by the time something is food for humans, it has already consumed resources in production and distribution and added packaging and other things to the waste stream.
But almost all of my compost is things like peels, seeds, coffee grounds, and the cut off ends of vegetables. Very little of it is actual waste.
As for the general topic, I wonder how much waste there is in places like Chinese restaurants. They seem to have large menus based on combinations of relatively few ingredients. It would seem to be something that would cut down on waste - that pork can go into ten different dishes.
Some of my compost is stuff like that, or egg shells but it’s also the French fries that were more than I could eat, or the omelet I couldn’t finish for breakfast. Between the compost pail and the recycling bin, my regular trash bin is dry, smell-free and takes weeks to fill.
I just read the Dunkin Donuts here throws out not only dozens of donuts at closing time, but pans of eggs and bacon and bagels that they use to make sandwiches. 
They will give it away if you buy something and just ask, but … I once got a slice of Sbarro pizza at the food court just before closing. I didn’t even finish it while I watched the worker throw three whole unsold pizzas left over into the trash.
I always hated that when I worked in restaurants. I mean, if we could have taken that food home, there would have been times where we would never have needed to buy groceries.