What foods make you drowsy and what foods make you awake? I just had dinner and I can hardly stay awake even though I took a nap today. How can one eat to feel awake? Before going to sleep, what should one eat to become sleepy?
For not feeling tired after eating, try eating smaller meals.
For example at work, try having two lunches, (or morning tea, lunch, afternoon tea), rather than one big lunch.
Avoid sugar during the day.
I find something with carbohydrates is quite helpful at work (eg. sandwiches), but you might want to try a low-carb diet.
For feeling sleepy at night, the opposite isn't going to work. Don't try eating a large meal to put yourself to sleep - you won't get a particularly restful sleep.
Do have dessert, I find the sugar helps put me to sleep.
Also, avoid coffee in the afternoon, and get plenty of exercise.
Foods that help you sleep
My go-to sleeping pill food has always been the banana: "an excellent source of magnesium and potassium, which help to relax overstressed muscles. They also contain tryptophan, which convert to serotonin and melatonin, the brain’s key calming hormones." (Source.)
You may have heard the myth that turkey can send you to sleep because of the tryptophan - you actually need carbs as well, as they "stimulate the release of insulin. Insulin, in turn, makes it easier [indirectly] for tryptophan to enter the brain." (Source.) So a banana's ideal for this, as it contains both tryptophan and carbs. This may also explain another answerer's suggestion that sugar sends him to sleep.
(Warm milk probably does nothing but act as a placebo, by the way.)
Other suggestions I've seen (that you may wish to take with a proverbial pinch of salt) of sleep-inducing foods include almonds, miso soup, cherries, and oatmeal.
How to feel less sleepy after eating
Three articles that might be useful on this front:
Those articles' most useful tips for staying alert include:
The first two articles list a number of foodstuffs that they say contain certain nutrients that fight fatigue. I'm not convinced of the science behind them, but you may want to look for yourself and try things like dark chocolate, walnuts, whole grains (for both complex carbs and fibre), citrus fruits.
Personally, I think what's more important than looking to specific superfoods to wake you up, though, is eating light and nutritious lunch that's free of sodas, sugar and typical junk foods that will spike your insulin massively and send you into a food coma.
In general: why we get tired after eating
(Because a bit of background info might help you find your own tips!)
There are three main physiological reasons one can feel sleepy after eating (from the Wikipedia article for postprandial somnolence):