The hypothesis that people on average will cut the calories in their orders when the amount of calories is labeled looks very non-obvious. I can see several opposing factors that might be in play when the restaurant starts to make nutrition information available:

• some people see that they should be eating less and order less
• some people see that they should be eating more and order more (but maybe they will eat less in other places?)
• some people see that they should be eating something else and order something else
• some people decide that this restaurant is unhealthy and come there less often (other less conscious replace them)
• some people decide to order less but come more often because they become more hungry
• etc.
• some people don't care

I think it's presumptuous to conclude that labeling the amount of calories in food "totally fails to change people's eating behaviors at all", but rather that measuring the average calories in the orders is not enough and more thorough investigation is needed.