Purpose Our purpose was to inquire into the differences in the results produced on the effectiveness in learning by the structure of the contents of the lesson, with youth's nutrition, especially the decision of the required amount of nutrition, as the subject for our study. The experimental lessons were conducted in two groups ; one group used as the chief teaching material a textbook(T)which gave disconnected, insufficiently related explanations of the grounds for the decislon of the required amount of nutrition (Contrast Group), and the other group studied the lesson with the same textbook plus the well-arranged and better-related explanations of the grounds (G) for it (Experimental Group).
We also tried to make clear in what items of learning difficulty lay and why they were difficult in this lesson．
Method The four different types of experimental lessons were conducted as described below. They were all conducted at Junior High School attached to the Faculty of Education, Shimane University.
(OHP : an overhead projector ; bw : the blackboard writing ; oe : the oral explanations)
<tt>
Group Structure of the contents Learner
of the lesson

Contrast (a) T 21 girls of 1st Year, Class 1
┌(b) T + G (OHP) 21 girls of 1st Year, Class 2
Experimental｜(c) T + G (bw) 20 girls of 1st Year, Class 3
└(d) T + G (oe) 21 girls of 1st Year, Class 4
</tt>
No significant differences were noticed among the four groups in the differential in intelligence.
Results(1) In answer to the teacher's question none of the students in the Contrast Group gave the necessary grounds for the decision of the required amount of protein, while in the Experimental Group quite a few gave satisfactory answers. (2) The understanding about calorie and the amino acid seemed to be difficult for the first year students of junior high school.