A low-carb (I prefer to call it "normal-carb") diet only works if the diet is properly followed and that exercise is a major component of the program. At least that is my experience.
I went from 300 pounds last April 1 to 199 pounds presently, which puts me in the normal weight range for my 6'3" height. I would still like to get to 190 but those last few pounds are proving to be stubborn! Nevertheless, I have gone from size 48 "relaxed-fit-elastic-waistband" trousers to having size 34 trousers fit comfortably and I feel great.
But exercise is key. I walk several miles a day and even in the current cold snap, I get out there and walk. Yesterday, it was -8 degree but I still went for my usual Saturday morning 2.5 hour walk (about 10 miles). During the week, I walk at least five miles a day - more when I can.
Also, I never bought into the Atkins plan as written. I elected to go on what pretty much amounts to a "whole food" diet. A whole food diet consists of mostly meat, vegetables, fish, berries, nuts, yogurt, olive oil, eggs, cheese, etc. If it is a "whole" food or made from "whole foods" (such as cheese), I eat it. If it comes in a package at the supermarket with a bunch of weird ingredients like "high fructose corn syrup" and "hydrogenated vegetable oil" then I avoid it.
The only problem I have with the Atkins diet is that they promote these low-carb "candy bars" and other junky stuff like that. Also, a lot of low-carbers want to literally "have their cake and eat it too." I am not convinced that Splenda-flavored cakes and pies is the way to go. In my opinion, things like cakes and pies should be eliminated from your diet whether they have a lot of carbs or not. (Perhaps they can be an occasional treat once you have reached your weight goal.)
As for the Subway sandwich, I did try one this week (without the ranch dressing which I refuse to eat because it has a bunch of artificial ingredients) and it was pretty good. I would like to see more restaurants offer this kind of fare as I'm getting tired of bringing a can of sardines or a bag of nuts to work with me everyday.