Meager means small and often applies to portions. Meager is the serving of chocolate cake your mother will allows you––or the amount of vegetables you actually want to eat before getting to that cake.
Meager doesn't mean adequate––it means not enough. People with a limited supply of food may try to subsist on meager portions. People who make a meager amount of money probably have a hard time making rent. Meager and emaciated both derive from the Old French maigre. If you can remember that you will look emaciated if your diet is meager, you’ll use the word correctly.
