1. Press F2 to put your hands up.
2. While your hands are up, open the inventory.
3. Right click on the meal or beverage, then eat/drink all.
4. Immediately after that, right click again and "cancel current action".
5. Immediately right click and eat/drink all again.
6. Quickly press the red "x" once to remove the item from your hands.
7. Press ESC, wait until the animation is done, then you can repeat all over again.