With JC they take all your measurements and determine which caloric level fits in with your activity level. It is all done in a program based on your BMR and all sorts of things. I am on 6400kj cos i am very active - lots of people are on 5000kj and it works for them, perhaps they are smaller than me and have less to lose therefore their body needs less fuel?
There are three levels 5000, 6400 and 7200 i think. Food is very balanced, i.e you eat HEAPS of veges, salads, 2 serves fruit, lots of grains, yoghurt etc.. i wouldnt by any means say JC is "unhealthy" 1190 calories and 1200 calories is the same thing. I cant fault the program so far!