Ian Somerhalder and Nikki Reed -- Happiest Healthy Couple

Ian Somerhalder and Nikki Reed don't just eat healthy ... they look damn happy doing it.

Ian and Nikki hit up the Farmer's Market in Los Angeles Sunday and the newly minted couple couldn't contain their happiness with fancy juice drinks in hand.

We're guessing it's because they both realize how hot their significant other is.

The couple's taking things to the next level ... attending the Creative Arts Emmys together Saturday -- and even adopting a horse.