Some people think that eating really light can keep you young. It is true that eating a third less then “normal” may make your life a full third longer! (based on scientific Calorie Restriction research).
But I think you can take it too far. If you reduce your eating by more than a third for long periods of time so that your lifestyle is about not eating enough calories, then it can actually age you.
Your cells are constantly dying off and new cells are constantly being formed. This keeps you looking young. If there isn’t sufficient material to build new cells from, your cells will get old, making you look older.
A rule of thumb from the Buddhist Monks: Fill 1/3rd of your stomach with food, leaving 1/3rd for the breath, and 1/3rd for the spirit. – This from a philosophy that embraces the power of emptiness.