A paleo how-to like everybody else... Anyway, it's a simple game of Don't Eat That But Do Eat This. Here's the strict version which is the one where you learn about yourself and shit. Do that. 80/20 becomes 75/25, becomes 60/40, becomes useless.
Disclaimer: When I started eating paleo, I didn't say "Okay, 30 days of strict paleo", I just decided to eat that way and worked out compromises and problems on the go. Right now I'm doing a full month of no treats and non-paleo foods because I didn't feel like I was in control of my compromises and it really isn't much fun and I can see how people end up binging on crap when the strict period is over. I want some food reward up in here but to be honest I will probably just make some paleo banana pancakes when September rolls round.
Don't Eat sugar, sirup, artificial sweeteners, natural sweeteners, juices, dried fruit. Grapes, plums, cherries (really easy to overeat and contain mild laxatives).
Do Eat fresh fruit, (unsalted) nuts, carbonated water.
Don't Eat grains, flours, rice, corn, legumes (including peanuts and anything with soy), white potatoes.
Do Eat vegetables, leaves, stems, roots, tubers, mushrooms (I cannot emphasize these things enough - also they are often expensive so look for cheap stuff e.g. cabbages and chard).
Don't Eat oils from any of the above (I have no idea how you make oil from corn but apparently that's possible) or the other hexane extracted oils.
Do Eat ghee/clarified butter or fat (e.g. goose fat) from pastured/grass-fed animals, olive oil, coconut oil.
Don't Eat dairy or dairy replacements (soy cheese, rice milk etc). Don't replace almond milk or "coconut milk" for glasses of milk or in lattes (coffee-flavoured milk, mmm).
Do Eat coconut milk in food or as a coffee/tea creamer.
Don't Eat processed meat like bacon or pretty much anything else cut in thin slices (except for carpaccio which isn't processed). You don't have any sandwiches to stuff them in anyway. Canned meat. Supermarket ground/minced meat - throw something nice-looking in the food processor yourself when you need some (or you get it from a butcher that you really, really trust).
Do Eat all sorts of animals, marine and land, and maybe try out some different kinds of offal (if you can eat brain you can skip fatty fish/fish oil/fish roe - just saying). Eggs.
Don't Eat preservatives.
Do Eat spices, herbs, and vinegars.
Don't Eat alcohol.
Do Eat fuck it, I don't think it's worth the stress to completely cut it out. Stick to a max of one unit of alcohol in a day. That's 3 cl (1 oz) of distilled alcohol like vodka. Shot or vodka soda.
If you are making a drink out of your booze remember to stick to water or carbonated water as your mixer (stick some lemon, cucumber, or herbs in there as well).
If you are (even undiagnosed) celiac beer is likely to fuck you over. Also wine and dirty spirits contain various irritants. Be aware!
Try to go without.
Do Eat (eat lots - much more than you expect - and don't let yourself go hungry).
Do it without cheating for 30 days (I would prefer you did it 6 weeks but I don't expect to ever get anyone to commit to that). If you do cheat then get back on the horse. Find out why you cheated and how to avoid it the next time you try to go 30 days (yeah, you have to do it again to get the full experience - don't go strict for a couple of months but use some paleo recipes, fats, etc then try). Don't add days in the end/start over immediately if you cheat, just complete it as originally planned.
Go here for more resources than I could ever be arsed to make in a lifetime: http://whole9life.com/2012/01/whole-30-v2012/
They have an e-book and a book-book but all the resources you need are available for free on their website (other great sites are http://www.marksdailyapple.com, http://www.theclothesmakethegirl.com/ and Google). Whole9 also has some guides on what to do after the 30 days strict paleo - I'll do a goals and evaluation of dietary changes post at some point hopefully. Maybe I'll even put a link here. In short it's about letting some things back in your life and see how you do then. Stuff like dairy, bacon, and for the more adventurous boiled/baked white potatoes (chips, crisps, and fries give me face zits and regular white potatoes give me arse zits so I tend to stay away from them - but different people are different). So you experiment with letting foods back in your life (basically the more calorie dense ones) when you've learned that you can live without them. And that you probably actually fare better without them.
Things that are different in my version:
I lump bacon and ground meat in the processed meat section - this is based on my own experiences when I was a paleo newbie. Today I am wary but I know approximately how much I can eat of it and from what sources.
Also based on my own experience too much fresh fruit can make your tummy a bit upset. But it's only really things like grapes where you are likely to inhale a pound in a sitting. They are very low in acidity so even if they don't have that much more sugar than other fruits you are more likely to overeat them. And they contain lots of tartaric acid, a mild laxative, and I want you to have normal poops.
Alcohol. Because otherwise I'd never get my parents' generation on board.
Adverse effects to look out for:
"Low carb flu", general lack of energy that lasts for about a 3-7 days often coupled with headaches (mostly women) or anger (mostly men - Finn Christo has a great post on it but you don't want to try paleo after reading it or reading this). Tips: 1) Be awesome like me and not have any problems or 2) Eats some fucking carbs. Various fruits, various pumpkins, carrots, sweet potatoes. There. Or just though it out.
Constipation. Yeah, avoid dying from that. Very rare and rarely serious and I think what happens is that yo-yo weightloss diets have decimated all semblance of muscle, even the smooth muscle surrounding the intestines so you can't move things forward normally. Or your gut flora was incredibly fucked up and has ended up in some weird dead end. If you haven't pooped in 3-5 days you should consider going back to parts of your old diet to get things moving or maybe try out some milk of magnesium (haven't tried it myself). Don't feel like a loser. Remember that I'm not a doctor - okay, I am but I'm not a medical doctor. So if you are sick of course you should contact your doctor but if they say that eating vegetables, fresh fruit, meat, seafood, and eggs is unhealthy and you should be eating grains and dairy by the fistful then consider a different GP. Especially if they don't mention soda and cakes.
tl;dr eat stuff that your ancestors ate 10'000 years ago
Extra reading: http://www.thepaleodrummer.com/2012/02/30-day-paleo-challenges-are-stupid.html stupid sometimes