For each meal, Jeffrey eats either toast, cereal, or pancakes. How many different ways can Jeffrey choose his meals for the day?

The question isn't sufficiently specific.

 

For instance, if there are only three meals and each of the three choices can be eaten only once per day, there are  3 x 2 x 1  =  6  ways.

 

However, if there are three meals and each food can be eaten more than once per day, there are  3 x 3 x 3  =  27 ways.

 

If there are more than three meals, then each food must be eaten more than once per day and there will be a different answer.