Question about nutrition analysis.

I have logged in all of my food for today and as I am very cautious of eating anything like cakes and biscuits, I logged in two slices of chocolate fudge cake just to try the analyser out. The calories of the cake added upto 800 more then required. But still the analyser gave me an A grade!!! how is that possible? can it not calculate that if i had eaten the chocolate cake I would have overate!!

The grade is simply an average of the foods you ate in the whole day.  If you ate a lot of vegetables and wholegrains as well as some cake then your average would still be good.  The grade does not reflect the total calories consumed.... that's something you have to judge for yourself, of course.