Really serious question regarding wasting money?

At school, I'm either pressured or hungry enough to go to the cafeteria during the break. In the cafeteria, we have cards that connect to our parents' credit card and each month they send how much money I spent the previous month.

Yesterday, my father noticed that I was spending a lot of money there (he doesn't usually look, and I spent about $70) and he demanded me to tell him what I bought there. I didn't want to anger him, so I tried to lie as much as I could, like saying I bought water when I actually bought a soft drink. Almost each day, I would go in the break to spend there $3 for a little snack made of a piece of cake and a drink. Twice a week I would buy there a meal, which go from $4.30 to $5.50. As an aftermath, he is telling me to give him an official paper stating exactly what I bought there the rest of the math.

Two things about this trouble me:

1. If he see's what I bought as too much (more than likely), I will have to pay for myself until the year ends.

2. He will probably want to see the whole year's statement of what I brought there, and if so, from what I know him, he will be upset.

What should I do now? Please answer seriously.