Maybe not definitive but here's my 2¢:
It depends on the situation.
I would say that if you're stuck in a life raft, not expending much energy, and not sure of a rescue timeframe it would be a good time to ration.
If your scenario involves cold weather and/or increased activity (like fuel gathering) rationing may not be in your best interest.
Another determining factor is your available resources. How much food do you to start with and can you augment your supplies from the environment? Also, how long will it be before somebody comes looking for you? What kind of weather conditions are you facing?
IMHO you can only have an initial plan and be aware that you may need to deviate from it. You have to know your options and when to implement them.
I tend to agree with your line of reasoning.
In a situation such as the life raft you mention above, there has been some debate here whether it's better to:
a) Eat your food (relatively) normally and then let your body go into
total starvation mode.
or b) Ration your food, stretching it out over a longer time period.
I've always generally thought option "B" was the way to go, but some here have argued that the body will actually do better under option "A."
Anyone have any linkable info on this?