My current diet:

it's flexible, and variant, yet very simple.
first and foremost, i eat local, seasonal, and organic as much as possible. Most of my produce is grown by myself or traded with friends, along with the animals products that either come from the 17 acres i inhabit on or sourced from near by. I have come to very much appreciate watching the seasons change (especially now that i am in north carolina where there are seasons!) and watching my cravings change with them.

i do have a few exceptions to my locality:
i consume coconut products like we are already out of petroleum. however, i use sources that support sustainability in there production.

I was a huge fan of cacao, but that's on hiatus, along with coffee. i still have pounds of vanilla beans i brought back while in Bali, which i have made tons of extract from that i use in baking and yummy drink concoctions.

fish: i buy vital choice sardines, and sometimes salmon. when i can...

florida or california avocados...

seaweeds, salts, some oils...

other then those delights (which i will enjoy until petroleum actually does run out, then i will get a dang boat and horse) i consume such things as....

-lots of green non-starchy veggies. whatever is in season. lately i've been into blending them into soups...its the season. I like wild weeds/ greens because they actually have minerals
-sprouts when they are over 14 days old
-fermented everything. seriously. ill ferment anything that doesn't end up too gross
-lately i have gotten into making raw goat milk greek yogurt; high in protein, low in sugars, almost -devoid of lactose because i ferment it so long. it's amazing the difference between raw milk, organic pasteurized milk, and normal milks. its like life and disease.
-eggs ever morning from my lady hens or ducks
-local fish, mainly we've got trout around here, sometimes i get line caught flounder from the coast or scallops/ oysters
-my partner and i raise chickens, ducks, sheep and recently cows. we usually have something frozen but i still buy other peoples animal products from around me
-the odd bits from other creatures. liver, heart...stuff that most people don't want. i am getting into mammals, but slowly. road kill is quite sustainable...and ethical.
-the non-lean parts of animals. i <3 skin
-local grass fed butter that i turn into ghee (clarified butter) great cooking oil!
-soon this pigeon that is driving my cats mad
-i always have bone broth going
-herbal teas, spring water that straight from the mountain side 15 min away.
-green juices...not fruit juices

i still like to eat things raw, but only things that CAN be digested raw, not brassicas (broccoli and it's relatives) and plants with oxalic acid

also, i eat a diet that is very high in fat, usually between 50% of my calories are from fat.
i usually only have one meal that is flesh based a day.

everyone is different, and everyone needs their own diet, their own food pyramid, as long as it's not devoid of fat!

No fear Vegetarians! I do feel like you can follow a vegetarian diet and still be healthy and sustainable.