As I said before - for almost two decades prior to diagnosis, as a result of concern over my mother's diagnosis of T2S, I did "everything" right -- I cut out most "refined sugar" from my diet - relegating those things to "occasional treats" - ate nuts and seeds, I ate probiotics (mostly in the form of yoghurt, which I HATE... ), I ate fish multiple times a week, exercised every day to varying degrees and mixing cardio with weight training. Yes, I fell into the low fat mentality to some degree, but supplemented with good protein mostly, rather than carbs. I lost just about all the excess weight I'd gained from my bachelor years - in a slow, methodical way, so as to make sure it was maintainable. I became accustomed to a fairly low-calorie diet of 1400-1600 calories a day - quite few, considering my activity level.
Like you, when I was diagnosed with, the dietitian wanted me to significantly INCREASE my food intake - all the was to 2750 calories, 40-50% of which should be carbs (75-80g per meal, plus two 25g snacks). I stood my ground there and refused to even touch that much food on a daily basis! She "compromised" at 2200 calories, though I walked away shaking my head. Even without increasing my intake at all or decreasing my activity level, once injected insulin became my treatment, the pounds piled back on. It's taking incredible effort to even make a dent in that weight gain -- and with no help at all from my physicians, who do not see it as a problem.
As to "healthy diet" -- that really depends. Over the last several weeks, I've been working with a functional medicine practitioner and trying to change things toward the more healthy direction; however, if it is true that the real culprits are the additives, antibiotics, pesticides and other contaminants in the food supply and the only answer is a purely natural, organic, whole foods, "clean protein" (as in grass-fed meat and pasture-fed chickens, for example) -- all things that I have been trying to follow, at least for the last 6 weeks (with some lapses along the way...), the problem will be economy. I currently do have a better-than-average income and access to many "healthy" options, but I can see that just over the last six weeks my food bill has MORE THAN DOUBLED, and my resources are being taxed to the breaking point. Granted that I have some additional challenges, as I keep Kosher. Where I live, grass-fed kosher beef FIVE TIMES the price of the other meat; paster-fed chicken is THREE TIMES the price, as are their eggs. Dairy from grass-fed cows is only double the price, but, for now in this program, I have been told to severely limit dairy. Organic produce is anywhere from double to four times the price -- and again, due to some esoteric Kosher considerations, not always readily available. The choices are simply NOT GOOD. I can see that, barring some significant change in my situation, I will not be able to sustain this way of eating for long. Sure, I can handle the macro-nutrient concerns (in fact, I am eating a lot more in this program than I did before), but not the specifics.
And this is on a 'high-middle-class" salary. I can't even imagine how someone of more moderate means, let alone a retired person on a fixed income, could handle it at all. And in the end... IS THIS REALLY THE ANSWER? Or is the whole thinking just another red herring from the "medical" or "alternate medical" community? I don't know. So far, my results don't seem to justify the cost or effort, in my opinion....