Why doesn't Ender have to eat all of his food?

Question

In Ender's Shadow Bean is informed that everyone in Battle School must eat all of their given food:

Your portions are scientifically calibrated to meet your dietary needs, and in the future you will finish every bit of what you are served."

However, in Ender's Game we learn that Ender "always" leaves food over after each meal:

Ender laughed. "I'll setup a system for you."

"Now?"

"Can I finish eating?"

"You never finish eating."

It was true. Ender's tray always had food on it after a meal. Ender looked at the plate and decided he was through. "Let's go then."

What makes Ender special? If anything, wouldn't the school be more on top of what Ender eats?

Answer 1

This isn't directly addressed in canon, however:

• Bean is extremely small. This is due both to

  • his young age - he was sent to Battle School at 5YO

  • his Amsterdam street upbringing. He lagged in sufficient nourishment for 5 years which makes humans grow up stunted even in subsequent years

  • and {{spoiler alert for sequel books}}

    because Anton's gene that was turned on in him makes his growth pattern to differ from baseline human child.

  At age 4 he was listed to look (size wise) as a normal 2.5 year old.

  This size issue would definitely necessitate the adults running the Battle School to be intent on feeding Bean up, because he clearly lagged what his mass and size percentile would have been for a normal child, and undernourishment is scientifically demonstrated to cause delays in both physical and mental development. So it was highly important as far as Bean was concerned, from their point of view.

  Bean agreed that this was the reason:

  Bean soon found out that his size was going to get official attention. When he brought his half-finished tray to the disposal unit, an electronic chiming sound brought the on-duty nutritionist to speak to him. "It's your first day, so we aren't going to be rigid about it. But your portions are scientifically calibrated to meet your dietary needs, and in the future you will finish every bit of what you are served."

  ...

  And he would have to start exploring soon. His exercise was making him stronger, and he was staying lean by not overeating -- it was unbelievable how much food they tried to force on him, and they kept increasing his portions, probably because the previous servings hadn't caused him to gain as much weight as they wanted him to gain.

• Bean was tagged for leaving half of his food on the plate (see quote above).

  It's not clarified, but it's possible the automated system doesn't flag if only a little food is left.

  And we aren't told how much Ender leaves - it's quite possible he simply never finishes because he's thinking; and leaves a little - not enough for automated system to flag him, and not enough to impede his physical growth.

• Bean is still a younger child. By that time, Ender is older (Bean is ~5, Ender is {hat/tip to ibid for correction} almost 7); so Ender is allowed more leeway in his food as is generally befitting their age differences in real world.

Answer 2

The difference is that Ender is already obedient, so no one care if he breaks small rules. Bean is rebellious, so he gets harassed about everything.

The difference between Ender and Beans is that Ender is the best at everything, but Bean can avoid the problem in the first place.

Here are some examples.

Ender beats a much larger boy in a fist fight. Bean traps a boy using a mob.

Ender beats the Giant's drink Bean does not play the game, to not have his psychology profiled

Ender is the best at the zero G game Bean figures out there is no reason to care if he wins or looses. He also just cheats

Ender beats the "simulation" with impossible odds Bean figures out it's not a simulation

So at the end of the day the academy needs to teach the two characters different things. Ender needs to learn to be tough. That only he can save himself. He is treated with hostility, put in bad situations, and is overall hardened.

Bean does not need to be hardened. The streets did that already. Instead Bean needs to learn to respect the chain of command. To do this they try to make him follow every rule to the letter. This includes eating his food.