Sentence 1: Jake had a weight problem. 
 Sentence 3: When, Jake's diet didn't work, he began to exercise 
 Sentence 4:  Jake lost all the weight he wanted to lose 
 Sentence 5:  All of his friends are proud of Jake 
 Option 1: Jake went on a diet to lose weight. 
 Option 2: Jake went on a diet to gain weight.