Purists are very loosely defined around here as those who concentrate on getting most, if not all of their foods from natural sources, not from processed or convenience foods. They carefully observe their their body's reactions to things over time and adjust accordingly in the natural direction.
I would venture to say that those of us who have become purists also had no intention of doing so. The trouble making that particular decision in advance is that the results of that decision are not UP to you, they are up to your body. Each body is a little like a snowflake, and yes, it can take a lot of time to figure out your own personal snowflake.
And perhaps the most frustrating aspect of the process is that most of us have to acquire this individualized knowledge via lots of little tweaks and changes as we slowly peel off the layers of weight. In MOST people, the diet that takes off the first layer rarely works for the rest.
It's a little like saying I have no intention of becoming a diabetic, or an alcoholic. If your body decides to become a diabetic or an alcoholic, you can choose to address that or not—and ask any medical professional, plenty of people people "decide" not to. In these instances, doing it (or not doing it) is deciding it.
If your body goes only part-way on untweaked lowcarb, as I would say a good number of bodies do, then you get to decide whether to go on with some changes that will bring further weight loss progress, or you will need to learn to be content with the results that do not square with how you had this whole journey planned in your head.
You may have no intention of eating like a purist, and that absolutely MAY work for your body, that depends on a million variables, variables that can even change over time. But if you decide this now, you may also be deciding that you are gonna be content to weigh a lot more when you're "done" (changing) than you expected.
