I'm going to answer the first (and possibly third) part of your question:
is knowing the persons age,bmi and allergy enough to make him a weekly
And to that I can quite easily say no, it isn't. Even if we were to take 'allery' to be all sort of food restrictions (eg, religious (Kosher, Halal), intolerances, vegan, etc.), and ignore the medical/nutritional issues, just some of the considerations that I can think of would be:
What sort of activities does this person do? A person who sits all day in an office is going to need a different caloric intake than a tradesman who's on their feet all day.
What are the person's skills? If you have a novice cook, you're not going to get them to cook complex things ... yet someone who loves to cook might be put off by things that are too simplistic. Even something as simple as dicing an onion ... someone unskilled with dull knives might take 10-20 min to do a bad job (from crying, etc.), then someone with with skill and good knives could get it done in under a minute.
What other resources are we dealing with? It could be appliances to work with (eg, not everyone has an oven, much less a food processor) ... or time, or money, etc.
What time of year is it, and where do they live? Not all places have access to fresh vegetables year round, and other places may not have access to canned or frozen. We tend to select 'lighter' foods and eat less when it's hot, and we may be more inclined to go with uncooked preparations, but cold meals aren't as desirable in the middle of winter.
What does the person like to eat? Someone who loves italian food might not like indian, and visa versa
And that's only scratching the surface.