Food for Thought – Is Costco Really Worth It?

I just finished a very interesting book. It’s called Mindful Eating by Brian Wansink. It’s a fascinating book, but then I love stuff like that. I am probably a frustrated psychologist because books about why we do the things we do fascinate me.

Brian Wansink is a famous food researcher. He runs the Food and Brands Lab at Cornell University and he spends all his time trying to figure out why people eat the foods they do, and why they eat so much of it, even when they know it isn’t healthy behavior and want desperately to change.

One series of experiments in the book really got me to thinking along financial lines. Over the last decade or so, the American public has developed a huge love affair with warehouse stores like Costco, Sam’s Club, etc. We love the idea that we are saving so much money by buying things in large bulk packages. However, Brian’s lab testing proves that this might not be the case.

He did a whole series of experiments based around portion sizes – trying different sizes of plates, containers, scoops, and utensils. In every case, when the subject was given a larger container of something, they found a way to use it up more quickly – a lot more quickly.

It didn’t matter if it was food, laundry soap, paper towels, or whatever, they would use it up to 20% more quickly than the same item in a smaller container. So, unless you saved 20% on the Costco item vs. the grocery store item (unlikely), you’ve just blown your savings and then some.

There is just something in the human brain that wants a “manageable” amount of a product on hand, and we will find any number of ways to make that happen, including eating up the excess. The only item the subjects didn’t do this with was bleach, apparently because they had experienced the negative effects of over-bleached clothing.

The most interesting experiment was one he pulled on his own colleagues – researchers with advanced degrees who study this sort of thing for their life’s work. And yet when he threw an ice cream party for them, they fell for his tactics just like anyone else. The table with the most flavors of ice cream and the largest bowls, scoops, and containers out-gobbled the table with normal portions by a significant percentage.

So how can you put this knowledge to work in your financial life? The answer may not be to stop shopping at your favorite warehouse store, but just be a little smarter about it. Here are some ideas that might help:

– Go ahead and buy the large box of pasta, but don’t keep the box on your shelf. Transfer about half of it into a Tupperware container and stash the rest out of sight.

– Don’t cook extra “for leftovers”. When you cook extra, your family just eats extra helpings without thinking, even if they aren’t necessarily hungry for them. Use trial and error to determine what the appropriate serving is and then write down the measurements for next time.

– If you buy large bags of chips or cookies, pre-portion them into baggies or other containers. Your family will appreciate the convenience of the grab & go bags, and the treats will last longer.

– When you cook, pre-plate the high calorie, high dollar foods (like meats) at the stove. Family members likely won’t travel back to the stove for extra helpings unless they are actually hungry.

– Conversely for foods you want your family to eat more of (fruits & vegetables), make larger servings, keep the serving dishes on the table, and put them towards the front of the fridge, or in a bowl near the TV.

– Prepare fewer varieties of food for a meal. We all know that M&M’s taste the same no matter what color they are, yet subjects ate significantly more of them when there were 10 colors than when there were 7 of them.

– For items like laundry soap, mark the desired amount clearly on the measuring cup, and consider keeping a smaller container for everyday use while stashing the large container out of sight. Out of sight, out of mind.


  1. Great tips. We LOVE Costco. I have no idea how much it saves us, but I know it is a TON!

  2. Adrian, it’s so funny that you posted this blog because we just renewed our Costco membership today after not having it for 2 years. 🙂
    I find it easier for a few different reasons; we make our daughters’ lunch every day. If we don’t buy bulk then I’m at the grocery store all of the time, and I like having a lot of produce in my house. When that runs out I start to snack on starchy foods that don’t sit well with me. Again, I don’t want to be at the grocery store all of the time.
    On the other hand…my husband had to remind me not to “get sucked in” to the extra goodies, blankets, jackets, rugs, dog beds, etc.

    Thanks for the post! 🙂

  3. I do enjoy shopping at Costco. We actually do break up the larger containers into smaller ones simply for storage reasons. But I’m glad to know it might also be helping us use it a little bit less!

  4. Adrian: Thought-provoking post.

    I wonder if people go for the heaping offerings so as to be polite …like not eating the last slice of pizza.

    Also: why do free samples taste so good? Costco is good at this technique. They give you a teeny taste and next thing you know, you’ve loaded your cart with a $40 box of whatever it is you tasted.

    Love your blog.

    Happy Home Companion

  5. Great tips. I’ll use some of them.

  6. Ah, so true. I buy some stuff “bulk” when we’re in the States and really struggle to make it last when we get back home. I’ve definitely seen that the big containers go faster. When I buy family-size containers of peanut butter, for instance, I can count on one jar lasting about 2 weeks. If I buy a case of 18oz jars, a jar still lasts about two weeks. Interesting that someone else actually documented this phenomenon!!! ;^)

    I’m enjoying reading around your blog! Have a great week!

  7. Great tips! I read several that I can use. Thanks.

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