Americans are fat. True. Americans are capable of making intelligent decisions with regard to their health when presented with all the facts. False to the power of 100. The FDA has suggested that restaurants provide healthier foods and more nutritional information to their customers. The idea being that, when presented with better options and knowledge, people will chose differently and eat fewer calories saying, "If companies don't tell them, people have no way of knowing how many calories they are being served at restaurants. And chances are, they are being served a lot more than they realize." (I'll wait for the laughter to die down now.)
Every box of twinkies and ho-ho's has nutritional information printed right on them. Trans fat info has even been added to the mix recently. Are people not purchasing that junk food anymore? Of course not. Even people who never eat out are not likely to know how many calories or fat they consume because people just don't check. Even those that do look don't likely follow the recommended serving sizes. Most looking is more along these lines: "Wow, when I finish these three burritos I will have consumed my saturated fat for, like, the whole week, and my salt for a month! Cool." People do not portion correctly. They don't keep mental totals. Making these changes at restaurants will not do anything to change how fat Americans are.
Three things: first, yes, some people do pay attention and portion correctly. They also don't eat out much, and when they do they have a fair idea about what they are consuming. Also, they aren't fat. Second, while people eating more food (# of calories) is a problem, the larger problem is people getting less exercise. The crazies who compete in ironman triathalons can consume 10,000 calories a day and not gain fat. Someone who works from home and gets out once a week to go to the grocery store for ding dongs and butter may be getting fatter even if they eat less than 2000 cal/day (yes, this depends on body size/type & even the type of work).
Third, homeostasis. The human body is a rather amazing thing. A really nifty thing that it does is regulation to maintain homeostasis. Basically this means if you eat 2000 cal/day you will burn 2000 cal/day regardless of exercise. It also means that if you happen to eat less or more on a given day you will burn less or more to accomodate it. This happens through several pathways including nervous twitching and heat production. One of the extentions of this is that fat on body does not necessarily = unhealthy. Losing weight (specifically fat) is something your body fights. You must exercise to (properly) lose fat. Fat burning starts only after all the readily available sugars have been burned, typically ~30 min aerobic workout, which means that exercise for 1 hr straight every other day actually burns more fat than 30 min/day (#'s vary somewhat person to person). If someone starts exercising daily (less than 30 min at a time) and eating more healthy foods, then that person may not lose a single cm from their waist, but he/she is getting healthier.
The homeostatis thing is also why dieters frequently yo-yo. When eating less, the body lowers calorie burning to accomodate as well as it can, below that it must burn the reserves (fat, then protein...the latter of which is bad). When coming off the diet and eating normally, the body will react by...not burning more calories until it has replenished its reserves, meaning building fat. Fat reserves will actually build up faster than they were depleted, making the dieter sad, and resulting in another diet. Over time this will reek havoc with the body and the dieter will die earlier.