20g carbs is not easy and means you have to keep checking your intake all the time because a small change can make a difference. That's why I have the same food every day for a week. I use a lot of tofu (no carbs) and tvp (not too many carbs, especially if mixed with tofu. It is easier for vegetarians as opposed to vegans. Double cream, eggs, camembert cheese and mayo have negligeable or few carbs and make you feel full up.
My breakfast is 2 eggs, loads of fresh spinach and loads of mushrooms.
Lunch is 1 whole large avocado filled with mayo and 1/4 of a round camembert.
Evening meal is a tofu+tvp burger with a veggie Caesar's salad - very filling.
I also have 3 soy protein isolate drinks a day and tea and coffee made with soy milk.
I add flax seeds to one drink.
When I feel tempted to drop off the diet, I have a small piece of cheese or some olives.
I intend to increase my carbs next week - I might include a half glass of wine at the end of the day. You go high as a kite on half a glass of wine, if you are eating very low carbs.
I would like to be vegan but cannot achieve that on 20g carbs per day, so must wait till I can afford to raise the carbs level.
It's easy to get flax, sesame and sunflower seeds here. I haven't check on nutritional yeast as yet. The great thing about Spain is that everything grows here and it grows bigger and faster, because we have so much sunshine and warmth.
PS Gary Taubes' book is very interesting, if perhaps a bit repetitive. Thanks for the recommendation.