Why do you need level 1 Pokemon to EV train?

[RedAlakazam]

Couldn't you just give them a bunch of EV reducing berries?
But how would you tell how many EV's they have? I guess that's the issue. There should be some way to track EV's.

I'm trying to figure out how to EV train. Figure out what pokemon gives what EV's and then I guess calculate on a sheet of paper? For each pokemon I beat, I add one of a certain EV unless holding whatever item to give +4 so I'll just trust that they will get +5 after each battle? Wish there was a way to know for sure instead of grinding my time away and end up doing it wrong. and still not being able to know I did it wrong because how do you know you EV trained right?

 

[Devalue]

Couldn't you just give them a bunch of EV reducing berries?
But how would you tell how many EV's they have? I guess that's the issue. There should be some way to track EV's.

I'm trying to figure out how to EV train. Figure out what pokemon gives what EV's and then I guess calculate on a sheet of paper? For each pokemon I beat, I add one of a certain EV unless holding whatever item to give +4 so I'll just trust that they will get +5 after each battle? Wish there was a way to know for sure instead of grinding my time away and end up doing it wrong. and still not being able to know I did it wrong because how do you know you EV trained right?

Moved this over to Pokemon Gaming Central. Deals with Pokemon game mechanics not restricted to a single generation.
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Usually begins with a level 1 Pokemon for two reasons:

1. Obtained a desired nature, ability, egg moves, and good IVs on a hatched Pokemon. Optimizes those much easier by breeding, generally.
2. Earned no EVs already. Takes a while to acquire berries, depending on the generation. Considers a freshly-caught Pokemon perfectly fine for EV training.

Some useful tips:

• Displays vague EV information in the summary page. Hit X on the stat screen with the hexagon. Should display rough information of its base stats in one color, and EVs in a second color. Sparkles if you maxed out the EVs in a stat.
  
  An example from Serebii:
  
  Used different colors in different games. Looks like Sun/Moon here. (Sort of sees some sparkles near Speed. Cannot easily screenshot it.)
  
  
• Feed EV-reducing berries to a Pokemon until it says the stat cannot be lowered any further.
• Tells you precise EV gains with Poke Jobs in Sword/Shield.
• Find the Effort Ribbon person. Awards a ribbon when you cannot gain any more EVs. Appears in Hammerlocke in Sword/Shield and the Battle Royale area in Sun/Moon, for example. Recalls an icon appearing in Super Training for fully trained Pokemon in X/Y/OR/AS.
• Recommends Serebii for Effort Value values. Go to the Pokedex for your game. Scroll down to "By Effort Values". Click on the stat you want. Sword/Shield example for Attack.

 

[Corveone]

Couldn't you just give them a bunch of EV reducing berries?
But how would you tell how many EV's they have? I guess that's the issue. There should be some way to track EV's.

There should. But since it's a poorly designed game mechanic with no appeal, they decide to hide it from players to not scare newcomers and casual players away. Sometimes in video games there are these kind of things that players are better off not knowing if they just want to play for fun.

You don't need level 1 Pokémon to EV train. Any caught or gift Pokémon will have zero EVs, so that's no issue. Level 1 is just what you'll end up with when you're breeding for Egg moves, IVs, Natures, etc.

 

[Sweet Serenity]

The absolute best way to keep track of EVs is to simply count them yourself when EV training. Make sure to take note of them whenever one of your Pokémon gains EVs. The best way to EV train if doing it the normal way is too complicated is to wait until post-game, breed and/or capture the Pokémon you wish to EV train, and simply give them vitamins.

 

[dewitlykefire]

Starting out with a Lv. 1 Pokemon is always the easiest because you're starting with a fresh default and basic set of stats. Depending on the Nature of your Pokemon, (which I always do), look at which stat is higher and start training that stat to the max first. In reality, it's just a simple and common idea of starting out fresh, regardless of nature. However, it's good to have a few extra of the same Pokemon just in case you find a certain Natured Pokemon a lot better.