Eggs and cheese. Nuts.
For variety, search up keto friendly recipes.
There are a lot of foods that can fit.
You can even get carb free bread and pasta that's different but pretty good.
Bread recipe if you want to make it yourself. There are many other recipes, but they pretty follow this idea.
https://www.dietdoctor.com/recipes/the-low-carb-bread
Ramen? Sure.
Use a veggie spiral cutter and run zucchini through it or find some carb free noodles.
http://mariamindbodyhealth.com/ramen-and-msg/
Waffles? Yep.
http://www.ditchthecarbs.com/2015/12/08/keto-waffles/
Snacks.
http://www.tasteaholics.com/keto-diet/30-low-carb-snacks-keto-snacks-to-enjoy/
I like this kind of thing:
https://www.franksredhot.com/recipes/zesty-party-nuts-RE0869-1
Pizza . Yes. Pizza, dammit!!
http://www.sugarfreemom.com/recipes/grain-free-nut-free-low-carb-pizza/
A bunch of different recipes
http://www.ketogenic-diet-resource.com/low-carb-recipes.html
BTW, all of those links are open tabs in my browser right now.
You'll find a ton more ideas on those sites.
Avocados are a great source of good fats and potassium.
Doing the low carb thing requires some awareness of what are referred to as macronutrients. For the most part that's the stuff that you see listed on nutrient labels on food. Make sure you get your salts, including sodium, potassium, and magnesium. Use supplements if you have to.
Also, don't over do the fluids. You'll wash all your electrolytes out of your system.
Try to be careful to not over rotate and eat tons of protein like chicken. It's good, but too much will require your kidneys to work harder. The scares around keto or paleo diets are usually due to too much protein, but the whole diet gets painted with scary brush.
I was borderline pre-diabetic - just about at the level to call it pre-diabetic. I did the 30 day Bacon Experiment and lost 30 pounds. I'm transitioning to a ketogenic diet and see it as a new lifestyle. I get my blood work done again in June.
My target is 20g carbs per DAY.