Stat foods can be great buffs, especially at lower levels. I'm a big fan of Halas 10lb. Meat Pies (food) and Grobb Liquidized Meat (drink). But they are expensive, especially for non-twinks at lower levels! So, here is the best way to use them and stretch them as long as possible:
How your food "auto-eats"
Whichever food or drink is in the HIGHEST slot in your inventory will be consumed first. (Highest is determined from top to bottom, left column first, then right column, top to bottom). FORCE FEEDING WASTES FOOD! You will consume your food and drink slower if you allow yourself to "auto-eat" from your inventory. Having said that, I will later be telling you to force feed! Doesn't make sense now, but it will...
How do I get the Stats without force feeding?
You get the stats from your stat food when it is in a higher inventory slot than any regular food. You are now "auto-eating" your stat food. If you only have regular backpacks, this means your huge Halas Meat Pie will have to occupy a regular invetory slot. DO NOT FORCEFEED YOUR STAT FOODS! Make sure that when you are not going into battle, that you have stacks of regular food and water ABOVE your stat foods in Inventory!
Going into Battle: Force Feed your Regular Food then Swap!
Wait! Force feeding wastes food! Indeed. But your regular food is MUCH cheaper than your stat food! So, before you swap that first slot backpack that has your regular food for that expensive Meat Pie, FORCE FEED YOUR REGULAR FOOD AND WATER TILL YOU EXPLODE! That way, when you swap around your inventory to put the Stat food and drink above your regular food, you are already "Stuffed". This decreases the likelihood that you will actually CONSUME your stat food! When you are going to have downtime, swap them back. Downtime over, force-feed regular food and drink, and swap again.
Using this method you can really stretch those stat foods and drinks. I'm afraid that you Kat Bards will end up eating more. Also, drink tends to go much quicker, so it is harder to stretch those stat drinks. /shrug. What are you gonna do?
I hope this little guide is clear and understandable, and helps you to maximize your hard-earned cash.