According to the USCCB
Fasting on these days means we can have only one full, meatless meal. Some food can be taken at the other regular meal times if necessary, but combined they should be less than a full meal. Liquids are allowed at any time, but no solid food should be consumed between meals.
So, yes, fasting means that only one full meal is to be eaten. We are allowed essentially 2 small/partial meals that combined do not exceed one regular meal.