It takes energy to digest food, and by the time evening comes around, we've already used up most of our energy — that's why it's best to eat a big meal in the morning, rather than the afternoon.
When Should I Have My Biggest Meal?
Ideally, it's best to eat your "heaviest" meal in the morning - carbs and protein are the best types of food to eat for breakfast, as they steadily release energy throughout the day.
If you make breakfast your largest meal, you'll have the rest of the day to burn off what you've eaten, and your stomach won't keep you awake at night by trying to digest your dinner.
It's important not to skip the evening meal entirely, though - your body does a lot of its healing when you sleep, and so you need to give it a bit of energy to help with that.
I usually have trouble getting to sleep (and very weird, unpleasant dreams when I do) if I go to bed without eating!
In Chinese Medicine
According to Chinese medicine, the stomach digests food best between 7am and 9am, and has the least energy to digest between 7pm and 9pm. You don't have to stick to those times exactly - I guess it varies, depending on your sleeping schedule - but the lighter your evening meal is, the better you'll feel.