I've had three experiences with low-carb diets, one after I left active duty, one while I was trying to get back on active duty, and the third one is the one I'm having now.
Most people, when they hear the phrase "low-carb diet" immediately think of the Atkins Diet, which is correct in the sense that the Atkins Diet is very definitely built on cutting down on your carbohydrate intake, but absolutely wrong in the assumption that Atkins is the only way to do this. As Gary Taubes pointed out in his book Good Calories, Bad Calories, low-carbohydrate dieting goes way back, back to the early 19th century, and for decades was considered the definitive way to lose weight. World-famous fatbodies like Chancellor Bismarck, for whom both jelly doughnuts and the capital of North Dakota were named, took up "banting", as it was called then, in order to drop excess pounds, and did a good job of it. I won't get into the history of why dieticians and other witlings got off on the wrong track and started pushing less practical and more mortifying diets, since Taubes does a good enough job of that on his own, but by the time the 1960s started fading into the 1970s, the conventional wisdom in the medical field was that only calorie restriction and exercise, preferably with a low-fat, high-carbohydrate diet, would do to get those unsightly, unhealthy pounds off. And if that didn't work for you, well, you must not really want to lose the weight. Still, even while this theory dominated the medical field, there was a continuing stream of booklets and diet plans built around the seemingly insane notion that in order to lose weight, the answer was more red meat, more butter, and less starches and sugars on your menu.
I well remember being handed a little blue booklet by my father in the spring of 1983. He'd dropped quite a bit of weight by cutting down on his carbs, and suggested I might be able to do the same. I didn't stick to it very well, but at least I didn't gain any weight while farting around with it.
That made it easier for me to try something a bit more hardcore in the winter of that year. I was newly married, the economy sucked, and my bride talked me into going on a "protein fast". This was basically a low-carb diet without the fat, and I dropped about twenty pounds in a month eating pretty much nothing but eggs and water-packed tuna, enough to get me under the weight limit to get back on active duty. That failed for reasons I'll go into elsewhere, but the doctor at the Minneapolis MEPS warned me to knock the diet off before I screwed up my kidneys with ketosis.
So I did.
Almost thirty years passed, and what with one thing and another I packed on the weight until in 2009 I weighed 440 pounds. A year later, after having left the hospital with the third serious infection in two years, my friends and family sat me down and read me the riot act. Part of the intervention had to do with my aimless drifting, careerwise; the other and arguably more important part was dietary counseling. Two of my friends were doing the low-carbohydrate diet and strongly recommended it; readings were recommended (including Hjalmur Stefansson's The Fat Of The Land) and support systems put in place. After one year, I'd dropped fifty pounds (I'd lost twenty pounds due to some minor surgery and a couple other stints in the hospital hooked up to intravenous drips) so that I'd lost seventy pounds off my peak weight. And that was taking into account three months where I hadn't done a very good job of sticking to the diet. I owe a lot of it to online tools like Fitday.com and Google Docs, which help my friends keep an eye on me and help me keep track of what I'm eating and how it contributes to the fat/carbs/protein mix. These days I'm eating a 65/10/25% mix of those, mostly meat, eggs and cheese, with the occasional non-starchy vegetable. If I cut out the cream in my coffee, Greek yogurt, and sour cream, I could probably get close to zero carbs, but keeping the carbs under 30g a day -that's about two slices of bread, for those of you scoring at home- is doing a good enough job of keeping my blood sugar in line and taking the weight off.
Do I miss the sweets? Not nearly as much as I used to. There are low-carb substitutes for a lot of things, and I'm fairly used to eating a monotonous diet anyway. Along with the support from my friends, there's an online support group at the Something Awful forums which contains a fair amount of useful recipes, food porn, successes (with pics) and exhortations from various denizens of the Low Carb Megathread. Good stuff, and I recommend it.
If you take away anything from this, take this: I am a not terribly well-disciplined guy who weighs far too much and is prone to falling out of dietary discipline when nobody is watching. Yet it works for me, and it will work for you if you need it to. On this diet, I managed to drop seventy pounds and get my fat ass off insulin, off blood pressure meds, and cut back on the glipizide; nothing else I tried, be it Slimfast or Weight Watchers, did me this much good for this long. Your mileage may vary - but I really doubt it.