The problem with most Americans is two-fold. First, they're uninformed about how to make healthy food choices in the first place. Some people think white rice is healthy! Others think granola bars aren't really candy bars. And most believe that cow's milk will somehow help you lose weight! These are just some of the many examples of nutritional myths held by most Americans.
Secondly, most Americans want instant results that require no effort on their part. So any advice that asks them to avoid certain foods, alter their tastes for foods, or engage in physical exercise is likely to be ignored.
Americans want magic results: diet pills, prescription drugs and surgical procedures that help them "automatically" lose weight while, presumably, they keep on eating all the garbage that got them fat in the first place. And what happens with the Atkins diet is that most people will pig out on bacon, cheese, steaks, milk and other low-carb foods for two or three days. Then they'll get a carb craving and have a "cheat" day where they pig out on white bread, breakfast cereals, soft drinks, candy and desserts. Then they're back on the Atkins diet for two or three more days. This pattern very closely resembles the sort of diets followed by Sumo wrestlers who are trying to pack on 200+ pounds of body fat: it's a cycle of carb starvation and carb indulgence that's guaranteed to make you fat. No wonder so many people fail on Atkins!
However, if people would actually follow the Atkins Diet as described in the Atkins Food Guide Pyramid, they'd lose weight rapidly, and they'd keep it off for life. The fact remains that people who fail on the Atkins Diet simply aren't following it. They're cheating in subtle ways that really add up, like eating pizza but not counting the white flour crust as carbs.
Regardless of the long-term popularity of the Atkins Diet, it has done tremendous good in raising awareness about the dangers of eating refined carbohydrates, added sugars and disease-promoting ingredients like high-fructose corn syrup. And that will be long remembered by the American people who are already causing major upheavals in the food industry by avoiding processed foods containing refined carbohydrates.