I have always thought that what you eat DOES make a difference, and have said so before in the face of the "calories-in/out" evidence. It's nice to see more and more medical evidence supporting the view that it does. (I haven't read the current all-the-rage book by Taubes, but I have followed various research articles that have come out before that support this conclusion. Will see if I can scare up a link where I mentioned a couple. My basic stance: nutrition is very complicated on the cellular level, but if you follow Michael Pollen's rules combined with No-S on the day-to-day level, you'll do fine.)
I also think that you
can "mess up" your body so that it functions less optimally than it would have otherwise - and that "than it would have otherwise" varies from person to person. In my case, I do think that years of No-S have restored some of the natural balance. I suspect that "good habits over time" would help other people heal/re-train their bodies, though it may take longer for more-damaged systems... and some people may never reach "normal" because of their own physiology.
Prior to No-S, I did a sugar de-tox every few months. When I was inhaling sugar, I needed about 3 days with no sugar or refined carbs before the cravings diminished. After that, I'd eat decently for a while, until the cravings came back. Lather, rinse, repeat.
With No-S, the sugar consumption never reaches the level where that's necessary. But... I've been doing it for years now.
So... keeping in mind that you are a beginner...
1) You may be confusing "sugar cravings" with "snack cravings" (particularly if you used to snack on sweets a lot, as I did.)
a. That's not important in terms of what you do - simply "be strict" until you retrain your hunger/craving. I recommend the "Strictness" podcast, which contains a lot of the rationale. If you're "starving," drink a glass of milk or distract yourself, and remember it does get better.
b. Even if technically this is a physical thing, I agree with Reinhard that using words like "addiction" or "craving" are generally not useful. (Major exception: If they help you release feelings of self-blame, which are even LESS useful, then go ahead.) In general, it's better to think in gentler terms, like a "tendency"... because it leaves you more open to your own ability to address these urgings. Which you can do, through willpower and habit. And can increase both through exercising them, just like a muscle.
2) There are two totally contradictory paths to reducing these cravings. Pick the one that works best given your personality/ability.
a. The "detox" or "jump in the deep water" approach - cleanse all carbs out the diet, like others have advised. Wait until you feel they're really out of your system, and gradually add back (starting with most complex) until you find your tolerance level.
b. The gradual approach. Limit the most egregious offenders (sugar, maybe refined flours) and GIVE IT TIME before you evaluate further. Cut back more only if needed after time. (In others words.... vanilla No-S, pretty much.)
"B" takes longer, but I think the changes you're looking for happen very naturally on No-S.
Also, I do think artificial sweeteners contribute HEAVILY to messing up your body.
(I acknowledge fully that this is a personal conclusion not shared by everyone - no need for anyone to jump in to disagree. Start a new thread if you must.) If you disagree, just ignore this idea. If you're open-minded about it, try cutting those too and see if there's any effect over time.
And "over time" is the key. If you have been overweight/dieting a long time, it may take years for your body to reset. The good news is that better habits will lead the way, and you can establish those better habits very quickly.
Good luck!
Edited to add this link, which mentions some of the research:
http://everydaysystems.com/bb/viewtopic.php?t=6977