How to stop my dog from eating grass, sticks, and leaves on walks?

What a cutie! Consistency is key here - each time he picks something up remove it from his mouth - you may need to bribe him with a treat to get him to release the item. You could also work on a cue like 'look at me' to teach him to make eye contact with you, and if you can anticipate when he's about to pick something up ask him to look at you instead: https://www.akc.org/expert-advice/training/watch-me-command-grab-dogs-attention/

Try keeping a toy or something that makes noise with you (you can put some pennies or pebbles into an empty soda or tin can and tape it closed to make a shake can that you can rattle or drop next to her to startle her into stopping) when you go outside with her. When she starts to eat weeds, squeak the toy or clap your hands to make noise to distract her from what she is doing and tell her 'drop it' or 'leave it'. As soon as she stops what she's doing give her a treat or the toy to play with. Over time this should give her the idea that she gets a nice treat when she listens to you when you ask her to stop. If she does not stop you may need to take her outside only on a leash so you can control her trying to eat weeds until you can break her of the habit. Some species of plants can be highly toxic to dogs (lilies, sago palm are two common toxic landscape plants) so teaching her to stop is a good thing.

If it is that big of an issue, I would look into teaching Snowball "Leave it". You can find various tutorials on YouTube that will walk you through it. Basically, it teaches Snowball that it isn't OK to just pick things up off the ground and eat them, and that she'll be rewarded for leaving it behind instead. Teaching other things such as drop/trading what's in her mouth for a reward, may also help. You should still be walking her, but you can keep an eye on her during your walks, and if you see her start to eat something, move her to another area, or remove the item from her mouth. If she's very mouthy and likes to carry toys, you can also bring a toy along on your walks for her to keep in her mouth and potentially deter on other things. If she does get into something she shouldn't and is ill, having your local vet's number on hand is always best as even the most vigilant of owners and well-trained of dogs can sometimes get into things they shouldn't.

IF there is a generalised increase in appetite and/or weight loss a full health check would be recommended to rule out medical causes of increasing appetite such as diabetes or poor digestion/absorption of food. Otherwise I recommend clicker training at home focusing on the words 'drop it' and I would also consider walking her with a muzzle on to prevent her from consuming anything dangerous

This is a common problem with puppies! They eat everything! There's not much you can do to stop the behavior other than stay by her side at all times and try to stop the behavior. You could try bring high value treats out with you and treat her when she is not eating the grass. This process may work but will take a while to train her. Eventually she will learn to pay attention to you. The good news is, she will likely outgrow the behavior. I hope this helps! Please feel free to post any other questions!

Yes, that is a tough one! It is important for King not to consume sticks, and not to eat a lot of grass. What about bringing out one his toys, and playing with it outside? Maybe he will enjoy being outside without obsessing about the grass and sticks? People even try sometimes using a basket-type muzzle, to prevent their pets from ingesting unwanted objects! This is not to be a punishment, just a prevention against eating unwanted objects! Hope this helps!

This is a common problem for many dogs! For starters, I would recommend not letting her off-leash until you have worked on her training a bit more - you can use a long line (a long, light-weight leash up to 50 feet long) to give her some freedom at the park while still having her under control. To teach her to come, first practice at home in a very boring environment. Use very tasty treats that she doesn't get any other time - things like chicken, roast beef, or cheese work well for many dogs. Call her name, and say "come!" in an excited voice. In the beginning, you can also show her the treats if you need to. As soon as she comes to you, give her a handful of treats and lots of praise. When she can do this in the house, try it outside in your yard on-leash. Work up to practicing at the park on her long line, always making sure that you have yummy treats to reward her with. Once she's reliable, you can begin letting her off-leash for short periods, as long as she always comes back for her treat when you call her.