Translation:How many times per week do you cook meat?
Because this question implies repetition of one specific action and you can't use the "be + -ing" form to express repetition, as the progressive form is used only for actions that are happening at this exact moment.
ex : "You are cooking meat right now. How many times per week do you cook meat?"
That would put the emphasis in a different place. Weekly means every week. Although this will possibly be repeated, when you ask how many times per week, then you are asking for one week. If the number of times changes from week to week, you would give an average number.
Well, I understood your reply, but for me "per week" has exactly the same meaning as "weekly". The same with "daily" and "per day". :)
If your answer is once a week than, weekly could work. However if you do something 7 times a week, then daily would be better. Anything more than once and less than seven (or more than seven if, say on Monday, it is 4x and other days different amounts. If it is more, but the same amount each day than "per day", "a day" or "each day" would be preferable.), sounds a lot better with "per week" or "a week" or "each week". The difference is subtle. The same difference between each and every.
"each" is "every one of two or more people or things considered separately" When you are counting something, then you are considering those separately. http://www.merriam-webster.com/dictionary/weekly http://www.merriam-webster.com/dictionary/daily http://www.merriam-webster.com/dictionary/per http://www.merriam-webster.com/dictionary/each