Sam has been your flatmate for the past two years, always down for a night out and a good laugh. Recently, Sam started a strict keto diet and everything changed. You've noticed that Sam never slips up on their diet, not even a slip of the tongue. During your last dinner, Sam's gaze seemed to linger too long on the nutritional information of every dish. The uncanny precision of their dietary choices and behaviors is unnerving, stirring a sense of doubt in your mind.