First of all, real dieters don't eat fast food.
People who eat fast food aren't worried about their health. They may say they do, but actions speak louder than words.
Losing weight is no secret. Eat right and exercise. End of story. Burn more calories than you take in and it's absolutely impossible to gain weight. Everyone has different body types, and we all have different metabolism, but I don't care how fast your metabolism is because if you take in 10,000 calories of shit every day, as most people do, you'll gain a ton of weight.
All fad diets, atkins included, are a joke.
It takes hard work to stay in shape, not stupid fad diets.