Many religions of the world have something to say about food, possibly also alcohol depending upon how you want to classify it. The objective of the thread is to look at the various ones around, and there are several choices and even more interpretations, and contemplate what it might be like if you tried to follow it. If you want to figure out whether you also don't want to wear leather if you are not supposed to be killing animals (or certain animals) then go for it.
Similarly we can ignore holidays as that would make things a bit complex. If you want to consider big ones like Ramadan (lunar calendar so varies a bit as the years go on, no eating or drinking or possibly smoking during daylight hours) and lent (forgoing a certain food, or perhaps booze or perhaps smoking for a month earlier in the year) then feel free to consider what goes.
Links to various ones.
Short overview of the bigger ones
http://www.chewfo.com/philosophical-reasons-for-food-choices/religious-dietary-restrictions/
Also good for some things
http://www.wsh.nhs.uk/ServicesAtoZ/...ofInformationonFaithsandCultures/Summary.aspx
Jainism
Probably the most strict of any here. lacto-vegetarianism for a start and possibly full vegan, however on top of that things which kill a plant to make (eating a grape is fine, digging up a bulb of garlic not to much. This does mean potatoes, onions and other tubers are out).
Eating at night (fires attract insects which is not good as they tend to fly into it) is discouraged. You may also have to variously filter or boil your water.
No fermented foods. Whether you can create vinegar and booze via chemical means and dodge the issues with killing yeasts and such I do not know.
No honey (counts as violence against bees)
Possibly always cooking fresh and avoiding anything that has started to turn (Americans might do better here, personally I will scrape the mould off cheese and carry on with my day).
Depending upon how you want to play it you may have to filter your water.
http://www.jainfoodie.com/jain-food-restrictions/
Hinduism
Definitely no cow based meats. Often some flavour of vegetarian. The calendar is quite complex if you want to go that way as well.
Buddhism
No specific rules, however if you are going to try not to harm living things as part of it all then vegetarianism is a popular theme.
Islam
Halal being a useful term here. It goes quite in depth and covers slaughter methods and protocols, however I will ignore that here as it ends up dead and ultimately tastes the same.
http://halalfoodauthority.com/definition-of-halal/
For most it would boil down to no pig products, no booze. Some sects view smoking as forbidden as well if you want to go that way.
Judaism
Kosher being a useful term here, though kashrut would probably be the more specific one. The Hasidic variation on the theme has differing and generally more strict interpretations.
No blood, no bugs, no pork, no hare, no rock badger, no camel (hooves is one of the common themes), no birds of prey/scavengers, no swan according to some.
No mixing meat and dairy.
Grape products not made by other Jews (kosher wine exists basically), not sure what goes for non grape booze. If you would consider missing your favourite type of wine to be a problem then OK, if any booze as long as it is booze works then so be it.
This can go on for a while, and that is before you get into food preparation (specifically the meat and dairy mixing stuff in the same pan/using the same pan, and mixing kosher and non kosher) but we can ignore that here.
http://www.koshercertification.org.uk/whatdoe.html
http://www.jewfaq.org/kashrut.htm
Rasta Ital is a term that works but not as well as the ones for Islam and Judaism.
Caffeine not being allowed is one of the bigger ones for most people here. Whether the mandatory marijuana is enough to settle the coffee withdrawal.
Some followers are fully vegetarian, others might do fish, others might do old testament style stuff against shellfish and pork and the like.
You may also be encouraged to watch your "food miles" and only do local stuff that is in season.
http://inityweekly.com/how-to-eat-the-ital-way-the-rastafarian-diet/
Sikh
Nothing particular but vegetarianism is a popular theme and even among those that might eat meat then beef and pork might be avoided. Curiously I think it is also one of the few religions that avoids halal -- halal will tend to accept food prepared by other religious rites but apparently not the reverse here.
Christianity itself has very little. Technically there is a thing about shellfish in there somewhere but nobody cares (it tending to only come up when someone says but the bible says) for the most part. A few of the offshoots have some things, some of the Mormon sects tend to frown upon caffeine for example. Equally if you go back a few decades there are some things that some still observed, things like fish on Friday ( http://www.npr.org/sections/thesalt...e-the-fishy-tale-behind-eating-fish-on-friday ).
http://www.nutrition411.com/articles/seventh-day-adventist-diet-0 has some stuff from the seventh day adventists (vegetarian for the most part).
Jehovah's Witnesses would have nothing but not eating blood, also smoking and drinking would be frowned upon rather seriously.
Quite a few things that fall under the umbrella of Christian emphasise trying not to be a fat bastard, it falling under gluttony if you fancy terms worth searching using, and it has some interesting implications for those places that practice it more strictly.
Baha'i
Mostly no alcohol, even as a cooking ingredient where it gets burned off.
Myself. Pork seems to be a popular one on the lists and I don't much care for it, doubly so for bacon which I actually dislike, so I can leave it out. The not mixing meat and dairy is right out though as I quite like a cheese sauce with some dead thing in pasta, or some dead thing topped with mashed potato, or some salad cream on top of dead thing in a wrap or sandwich.
I am a determined carnivore in most instances. It can be a long time between meat if I am on the road or being poor or something but I am not inclined to forgo it entirely. Meat with every meal is a marketing term as far as I am aware.
One of the links says some flavours of Vietnamese might not eat lamb which I could not handle. Love me some lamb, lamb liver and most things lamb actually.
The hindu (and some other Indian subcontinent) thing against beef I guess I could handle, however I do like a steak from time to time and it is usually readily available so I am quite used to having it.
No booze and no caffeine would be fine as well. I don't do well with the latter and though I have no objection to the former I don't bother with it these days so no worries there either.
