Final answer:
Lipids are the macronutrient that is water insoluble due to having more carbon than oxygen atoms.
Step-by-step explanation:
The macronutrient that is water insoluble because it has more carbon than oxygen atoms is lipids. Lipids, also known as fats, consist of carbon, hydrogen, and oxygen atoms. However, the ratio of carbon to oxygen is higher in lipids compared to carbohydrates and proteins, making them water insoluble.