Sentence 1: My health began to slip as I got older. 
 Sentence 3: I began to follow his advice while eating 
 Sentence 4:  I ate healthy foods for months and felt a change 
 Sentence 5:  Even at an old age, I felt healthy again 
 Option 1: My doctor told me my diet was fine and the problem was elsewhere. 
 Option 2: My doctor told me to change my diet to eat less fat.