So what does an average Keto breakfast look like?
Generally speaking eating any meat (beef, pork, chicken, seafood, etc) and most vegetables (pretty much any green vegetables) is the simplest way to eat a keto diet
I think breakfast is probably the easiest meal to do keto. Eggs and breakfast meat (bacon, sausage, ham, etc) are great on keto. Cheese is cool so you can do omelets (my wife doesn't really like omelets). If you want to get a little more complex, there are a number of recipes for keto breads that usually use almond flour or coconut flour, so I'll sometimes make pancakes, waffles, or bread for breakfast sandwiches from almond flour.
I know you didn't ask, but expanding beyond breakfast...
For other meals, like I said, meats and green veggies are the most straight forward meals. We usual try to cook stuff with a little oil to make sure we're getting enough fat. Full fat dairy is good so we cook with cream and cheese often. From there is just up to your imagination or your research (keto is super popular, so there are lots of recipes online).
Some of the tougher substitutions. Rutabaga is the best replacement that I've found for potatoes, but it's not quite the same. Radishes and turnips are also ok. For mashed potatoes, we'll often do cauliflower.
Cauliflower rice is an ok sub for rice depending on the recipe. There are companies that sell plant-based "rice" and "pasta" that are pretty good. Miracle Rice, Better Than Rice, PastaZero are a few brands that come to mind. But again, not the same. (Yes I know normal rice and pasta are already plant based, but that's often how they refer to their products) We experimented with making out own pasta from flour alternatives (almond, coconut, lupin, etc) but we haven't found a recipe that we liked.
When it comes to eating out, like I said, when in doubt, meat and green veg. Steak restaurants are pretty easy. Almost anywhere that sells a sandwich will sell it to you without the bread, and many will wrap it in lettuce instead. Sushi without the rice is one of our go-to takeout meals. Wings are good if you can find somewhere that doesn't put a breading on the wings. In general deep fried foods are good but no breading. BBQ can be ok if it's a dry rub and not cooked with the sauce already on it. (They do sell sugar free BBQ sauces.) But most BBQ places don't have compliant sides.
Salad can be great, but you have to be careful. A lot of fancier salads incorporate stuff that isn't compliant (e.g. beans, grains, fruit, carrots, croutons, tortillas strips, etc). For salad dressing you want either plain oil and vinegar or a cream based dressing (ranch, blue cheese, Caesar) but those can sometimes have some sugar in them. Lower fat dressings (Italian, Catalina, 1000 island, etc) usually have a lot of sugar.
Not many fruits that you can eat, but in small quantites, berries are ok. They have less sugar than other fruits and are lower on the glycemic index.
There are lots of sugar free sweeteners and desserts that you can buy. It's been surprisingly east to satisfy my sweet tooth.
I REALLY miss Tex-Mex / Mexican food. Like so much.
Ok, this had made me hungry,