Weight loss is affected by the number of calories taken in: the fewer calories taken in, the more weight loss. which is the independent variable?

The independent variable would be calories taken in.

Step-by-step explanation:

The main reason why calories taken in is the independent variable is because the amount of calories you take in is not directly affected by anything in the problem. It is confusing I am sure because you personally can control your calorie intake in real life, but think of it in context of the problem at hand. In the problem, the amount of calories taken in can directly influence the amount of weight loss (or gain) occurring, but weight loss (or gain) can only be influenced by calories in context of the problem, and cannot influence anything else.