Totally normal. I have 2 little brothers about your age and they said the same thing.
Answer: Psychodynamic Perspective
Explanation:
Psychodynamic perspective refers to the theories and therapies established by Sigmund Freud, and graciously supported and modified by his followers.
Psychodynamic perspective lays emphasis on psychological engagements or processes (such as behavior, feelings, and emotions), and establish that childhood or early life experiences are important in shaping adult personality and relationships.
However, psychodynamic perspective emphasize more on unconscious drives, which is a major stake in proper functioning of human.
I would tell them excersise more daily and eat nutrient things
Just try your best to get along with them. Starting drama will only make things worse, remember that she/he’s your coworker not your friend. You’re at work to do your job. With that said just play nice, take a deep breath and focus on the main task at hand.