For me and most meat only is a temporary thing to rebalance the body. It worked particularly well at eliminating gas producing bacteria and clearing up my gums. Post-meat only, I can eat vegetables that previously gave me gas and sugar cravings are lower.

I wouldn't worry about iodine if it's temporary. I did do "surf n. turf" for dinner which was seafood + steak/marrow and that took care of any DHA and some iodine requirements. I did surf n turf because most seafood is kind of lean and adding in the fatty meat really made it better. Salt and pepper are great seasonings, but other-non nightshade spices like cumin or coriander are great too.

Breakfast was eggs, lunch was LOTS of ground meat. Someone here was surprised I ate 300 grams bison, but on this diet I regularly did almost an entire lb a day (still do...).

I don't often have the foresight to marinate, but lime juice based marinades are great.

In my ZC days I basically ate the following:

breakfast (if I ate it at all, I'm skinny as hell so I don't fast very well) Hamburger or steak, unseasoned

lunch: steak

dinner: hamburger or steak

I quickly lost any desire for seasonings. I don't know if this is just me or a general thing but when all you're eating is a steak, salt and pepper quickly stop being compelling. Don't know why.

Cook it rare to preserve nutritional value (although that might just be superstition as some of the zeroing in on health folks claim/prove through eating only well done meat). Eat a lot of fat. Oh, LISTEN to your appetite! Don't eat unless you're hungry and when you do eat stop when you feel full.

You probably don't have to worry about iodine for a 3 week trial, or really much of anything given the short timeframes. The only warning I would have is that if you are not digestively used to a high fat diet, or are currently not firmly in ketosis, you might be in for a rough ride. This will pass as your body adjusts, providing you are otherwise normal, and it may persist for the entire three weeks of your experiment. I was ZC/VLC for about three months before my digestion came under control, but I also have Crohn's so I'm probably a bad barometer. Just be aware of the possibility.

Otherwise, have fun. ZC can be a liberating thing if you're the sort who just wants to refuel and move on with whatever else you were doing - you always know what you're going to eat, your body will tell you when to eat, and it's pretty easy (and quick!) to cook a decent rare steak with some practice.

edit: Comment reminded me to note this: http://www.dirtycarnivore.com/Lex.html

Lex Rooker has eaten nothing but raw beef parts for the better part of four years, and he ate cooked meat for a year before that.

The biggest danger you face is not having a health problem in three weeks on this diet. Your biggest danger is drawing incorrect conclusions due to three weeks not being enough time to really judge your response. As I mentioned, it took months for me to adapt, and I'm very glad that I stuck it out - if I had set out to do a three week experiment instead of a one year experiment, I would have failed rather than succeeded.

Skip the marinades and seasonings and just vary the meat. The best thing about eating large amounts of meat is actually getting the taste for it.

Try to buy all grass finished meats, and pastured chickens. They taste so freaking good you don't need any sauces.

If you must add flavor, use spices only. No salt. Recommendations: rosemary and black pepper for beef; oregano, basil, parsley and maybe some lemon peel for pork; black pepper and/or dill for chicken.

Make sure you include plenty of fat in your meat choices. Many cuts in the supermarkets are lean (even when organic), and you'll feel a lot better and more able to stick to your all meat diet if you include enough fat for satiety. I would think psychologically that quite a bit of variety would help you - plenty of different animals to eat. I find the meat juices themselves can quite easily be made into a basic sauce with a bit of water and if you're prepared to stray a bit, a few herbs and spices.

sea salt is rich in potasium, unlike other salts. Id use that. I make a bone marrow soup and render it down and use it when I cook. I still would carmelize some onions, garlic, etc- it is much better than any bottle crap which is the same thing and sugar.

The inuit do this successfully but keep in mind they eat all parts of the animal including organs. Muscle meat was typically considered the least healthy of all the meat parts and was giving to the dogs. They target the fat and nutrient laden parts for health. Most city folk probably would not want to eat the foods that the inuit eat regularly. In addition, finding healthy grassfed meats would also be an obstacle for some. I think it would be difficult, but not impossible, long term to be healthy on an all meat diet. For a short term trial, it probably would not be a problem provided your body, and especially your intestines, are able to adapt quickly to high protein and fat digestion.

Ordered a Quarter of natural grass finished moo cow. Going to all meat for 30 days and blog it I think, with photos. I'm already pretty lean, but I think it will take me from soft pack to 8 pack, we will see

I won't be eating offal, but fatty and lean cuts and cooking bones in crock pot

No multi, just some Salmon, Tuna, Forest Pig and Grass Beef

Spices just for flavor variety