The title of this post is a Zen saying. And that is what mindfulness is in a nutshell.
I have read most of the posts under the mindfulness tag in this forum- but actually have not found a single mention of a mindful eating advice.

Mindful eating the way I was taught can be summarised like this:

Look at your food
Observe the colours, the texture, the smells.
When you pick up your fork or spoon, notice the intention of picking it up.
Pay attention to your arm moving, to your finger grasping it, to the sensations arising at the touch of the fork (metal, cold, warm, smooth…)
Notice the intention of picking up the food.
Again notice the movements of your body while you do that.
Smell the food, and when you bring it to your mouth taste it – feel the texture, the taste, chew slowly, notice the moment you intend to swallow.
Notice how often the next forkful is ready to go into your mouth immediately after it has come out of it! When you become aware of this, place your fork on the plate. Wait until the first mouthful has been chewed and swallowed before picking up the fork again.
While eating do not read, watch TV , text …

If you find that your mind starts thinking or planning or worrying, bring your awareness back to the food.

And going beyond mindfulness, here are more thoughts that are changing the way I personally relate to food – probably too slowly and I still find myself binging every so often – but I still would like to share it.
Some posts have mentioned connectedness and how so many people have not enough food – and this something that reaches far beyond the act of eating mindfully: I think about the person that has prepared the food, about all the people that have made it possible for this food to arrive on my table, of the ones that have tilled the soil, planted the seed, watered and harvested, of the bees pollinating, the birds spreading seeds… I think of the person that harvested the rice I’m eating, and that maybe today they did not have a bowl of rice to put on their childrens table, and I’m grateful and saddened.

“to see a world in a grain of sand…”