Answer:
Differential susceptibility.
Step-by-step explanation:
Differential susceptibility: The theory is given by Jay Belsky, he stated that different individual is being distinguished in the degree to which they are influenced by qualities or experiences of the environment being exposed to.
According to him, a few individuals are more sensitive by these factors or influences as compare to others. And, these influences can be positive as well as negative. Genetics is one of the major reasons for this difference among people.
Similarly, in the case of Aaron deferential susceptibility occurs even after eating well and doing exercise regularly he developed diabetes in the seventies.