I'm all for this.
Consumers can make more informed decisions if they understand the health content of their meals.
Most people I know who are health conscious eat at home.
The government required labeling on all food sold in grocery stores more than a decade ago. This allows consumers to make better choices.
The market should be allowed to work. But as every student in the first class of Economics 101 knows, the market works best when people have as much information as they need to make an informed decision. The market works less well when one party to the transaction has asymmetric information over the other. There is too much regulation, but the best government regulation is regulation that makes the market work better. Food labeling is an example.
When people buy food, they often aren't making rational choices since choices are often driven by deep-rooted physiological and psychological impulses. That's why food companies spend tens of billions of dollars a year on marketing and product-testing, often at the detriment to our health. Giving people more information helps them make more rational and better choices.
As I stated before the issue is one of proper calculation, Packaged/canned food is created via mechanization, where they can be confident the exact same amount of each ingredient is added and their label information is accurate.
Asking a restaurant to weigh every single thing they put in, then weigh each portion as it is served is kind of ridiculous.
And this is coming form someone on weight watchers, who needs to know these things to track accurately. The thing is I know some places are doing the best they can, and I don't hold them to some high crazy standard.
The problem is we are a country of litigious assholes, and you know someone is going to sue these companies/establishments the second one of their calorie counts is off.