As a second year Nutrition student my experience here at Kings is very positive. I did IB before I came at Kings College. My grades were 37/45 but you can find all the specific entry requirements for both Nutrition and Nutrition and Dietetics online. It is a very interesting course as you gain an in-depth knowledge of all key aspects of nutrition, not only by doing nutrition specific modules but also endocrinology, physiology etc. The academic staff is very helpful and the tutors are always willing to help you. For almost each module (first year there are 6 modules) you will have to do a coursework that is separate from the exams, either a practical report or a small test. However, they will help you by giving you specific instructions and a reasonable amount of time to submit your coursework.
Hope I answered all your questions!