It's usual for me to ask for the main meal later in the flight so I can immediately sleep at the start of the flight (usually already full from HKG Pier F / JFK First Dining / etc). On the topic of multiple entrees, I have had crew practically force me to take a second entree because they think the first wasn't enough. (I guess I need to hit the gym more). That's most likely due to getting lucky with typically half-full F flights (other benefit is getting a second seat set up for your bed).