I'm doing South Beach-ish style eating right now to lose the 12 pounds or so I gained over the holidays and also because I'm gluten intolerant and shouldn't be eating lovely, delicious breads and other gluten-filled things, anyway. I say South Beach-ish because in the 4 days since I've started, I've broken down and eating half a milk chocolate bar and have had 2 iced lattes from Peet's. So I haven't stuck to the no-sugar part. However, I have not had any grains and have been eating a lot of good protein and vegetables.
I don't buy fully into the restriction of "healthy" fats in the South Beach diet... I have no problem with full-fat cheeses and dairy or olive oil and even some butter. I also prefer limited real sugar rather than fake sugar-free sweeteners. One thing the South Beach diet does get right is LOTS of vegetables and eating low-glycemic foods in general. So, I have been having vegetables with breakfast. As snacks. As sides. It's a much better way of eating than what I have been doing the past few months at least, which involved a lot of convenience food full of gluten.
Example of what I'm eating lately-
Breakfast: Asparagus and goat cheese omelette
Lunch: Baked cod and roasted cauliflower
Dinner: Chicken fajitas with onion and bell peppers
Snacks: Pistachios, celery with peanut butter (no salt, no sugar, just nuts peanut butter)
I feel pretty good physically eating this way and while I won't be grain-free for more than a couple of weeks, I will add back in whole gluten-free grains and fruit eventually, it is helping me to break habits of excessive sugar intake and promote eating more vegetables.