That's a good question, @Terry4. The answer, I suppose is complicated. For one, I think there is still some adjusting that will need to be done to it, especially if I want to achieve all the objectives I have with starting this in the first place, so I don't know absolutely how that will end. Beyond that, theoretically, it is sustainable -- mostly (as it stands now) a LC, moderate protein, moderate fat diet based primarily on "real, whole foods," and avoiding or minimizing some of the foods more likely to cause inflammation (though I'm not sure if that is really an issue for me). I've not been all that true to the full scope of the diet, in that I don't have enough of the fibrous veggies as directed, and deviate from the way of eating on weekends, but for the most part, I've been doing it.
The problems, for me, at least, are generally twofold: First, this way of eating, particularly if I do follow it completely, is proving to be a lot more expensive to me than my previous approach -- and, though I see some improvements, I do wonder, to borrow a business term, as to the real "return on investment" - am I getting enough gain for the cost? - as well as being unsure that I can financially sustain this approach. The other issue is that, at least at this point, I do find that I need to spend a lot more time thinking and planning meals -- and I'm not always satisfied. Not that I'm any more or less hungry than before (I still cannot use "hunger" as a measure of when or what to eat), just that I find that I don't always have choices that I want and don't always want the options that I have. I suppose that if the first of these two issues is resolved, the second will follow -- if I see affordable benefits or real value/improvement (which can result in lower other costs to help make things affordable), I could probably become acclimated to it all and find satisfaction that way.
Like I said - a complicated answer. During the dozen or so years before my Dx, I'd managed my weight, and supposedly, my health, with a diet of eating the foods I liked in moderation and exercise is ways that I enjoyed. THAT was clearly sustainable. I'm not yet sure this is.