what you eat can affect your life Think about it. Caffeine wake people up. For me caffeine is a no no. I flip out, get irritable, and want to scream, I also have very negative thoughts after drinking coffee. Some people can not function without caffeine. they become too dependent on it. So if you are eating something that makes you have a reaction like this, then it can affect your meditation. Other foods can affect your moods as well. Turkey has something in it that makes you feel sleepy. I can't remember what it is, but that is why people feel sleepy at Thanksgiving. So, in short, yes food can affect you. I read that you shouldn't be hungry or full while meditating, so that it does not affect you.
For me, the better I eat the better I feel. So in that, my meditation is better. As mentioned above, anything that stimulates or slows you down will directly effect your meditation. As one meditates more and becomes more in tune will all parts of his/her body, there is more of a desire to treat the body better.
what you eat affects everything. most foods are drugs to some degree, also proper nourishment affects your body chemistry. Some people find meats and heavy foods are a hindrance to meditation. The more you meditate the more you will be in touch with how minor changes in your diet affect you.
caffeine chocolate meat tobacco cola sweets they all effect your energy, prana, chi, or Ki These are not laws or commandments, you're not a sinner if you eat chocolate. but all these things will have an influance on everything you do.
I am 98% vegan (rough guesstimate), trying to get to 100%, been a vegetarian for 12 years. My diet is pretty good. I eat practically no junk food, eat out seldomly, and cook most of my own food from scratch as to be without all the chemical preservatives. No cola, no potato chips, no fast food. I don't eat a lot of bread or pasta - mostly brown rice, oats, nuts, beans of all sorts, tofu, and a wide variety of fruits and veggies. I've been off caffeine for years, although I will eat a small piece of ultra dark chocolate once in a while. I've never really had problems with meditation that I felt were diet related, although I try to meditate on a totally empty stomach, or no less than 3 hours after I eat.
If meat is presented to me, that I did not kill, and it's time for me to eat. I will eat. Otherwise, I seek to avoid meat as it kills the seed of compassion.