Ceviche is what happens when acid does the work heat usually does. Lime juice firms the surface of the salmon and changes its texture within about half an hour, and the result is bright and clean in a way cooked salmon never is.

One thing to be clear about: the lime is not cooking the fish in any food-safety sense. Citrus does not kill parasites. Use salmon that is already safe to eat raw, meaning sushi-grade or commercially frozen, and keep it cold the whole time.

Wild salmon brings the omega-3s, avocado brings the fat, and the whole thing lands at 2 g net carbs for a serving.