OT: what is the perfect snack?

If you are doing LCHF, a couple of things: (This is NOT the same as low calorie low fat approaches most people are used to!)

1. Fruit, especially the high glycemic fruits suggested (grapes, banana, pineapple) will make you hungrier because they mess with blood sugar. These may be considered ok for a standard diet but they are not good LCHF snacks. The OP stated she's following LCHF.

2. Snacks should consist of some protein, plenty of fat, and if you can "afford" some carbs, then a few non-starchy veggies too. Fat and protien satiate hunger and stabilize blod sugar.

Here's some examples--a few already suggested above--you can mix or match:
Hard boiled eggs (nature's perfect food!)
Celery with almond butter (peanuts are legumes, not nuts, and are less healthful than almonds, but ok if you choose. Sunbutter made of sunflower seeds is another option)
Roll slices of beef, chicken, or turkey around a pickle spear (ideally naturally fermented pickle)
Some cheese and whole almonds
Veggies dipped in full fat salad dressing
Half an avocado, or make some guacamole and dip veggies in it
Full fat Greek yogurt with a small handful of berries and some pumpkin and sunflower seeds
A cup of homemade broth
A cup of tea with some heavy cream or coconut oil (have a little protein too for best satiation)

If you are getting hungry and needing to snack regularly, consider increasing the fat in your meal, and make sure you're getting adequate protein. I rarely need a snack if I eat enough at meals--I can easily go 6 or more hours between meals because my blood sugars are stable, and I probably eat fewer calories overall without counting or hunger because my meals satisfy and don't spike my insulin.

Down 70 pounds and counting eating this way.

Excellent as usual, Janknitz. Thanks so much for the list--I needed that.

The reply about pineapple made me think - recently I had a serving of cole slaw with pineapple in it, and sweetened with pineapple juice - this may become my new favorite snack - how could it be any better for you than cabbage with pineapple?

Oh, forgot one of my favorites--sometime a snack, sometimes a meal (depending on volume):

Roll a slice of turkey or beef around a slice of avocado!

I also like to make a big, flat "pancake" of a beaten egg or two (with a squirt of fish sauce for flavor) and then mash avocado and roll it up in the egg pancake.

Pork rinds. No carbs; the rest is half fat and half protein. Just salty enough that I can't stand too many.
Kale chips: I tore dinosaur kale into pieces, shook with olive oil and a little salt, and baked on med/low until leathery.
After cooling, they crisp up. Mmmmm, kale.
Anything pickled--gardiniera, beets, cukes, especially Claussen Smalls. Yum!

Air popped Popcorn, no butter, super light salt... high in fiber and it digests easily. Almonds, pistachios in the shell plus any light oil content tree nut. Some fruits like fresh apples, pears and such are moderate in sugar (fructose) and high in fiber so they might be nice on the side with the above mentioned items. I used to like high protein stuff like tuna fish or unprocessed lunch meats with some RyeChisp crackers but lately I've been staying away from anything too heavy before bedtime. You might have a different view on that. Hope that helps.

I was told that most non-tropical fruits and berries is good.

If you're eating low carb, pork rinds can't be beat! The salt and vinegar flavor are great if you can find them.