Is There a Connection Between Credit Cards and Weight Gain?

There is an interesting phenomenon going on in the world that recently caught the clinical eye of researchers – as credit and debit card use is skyrocketing, so is the obesity epidemic.

Could one have anything to do with the other? Is there something about using credit cards for food purchases (a relatively recent trend) that contributes to weight gain? In 2006, nearly 40% of all purchases (including food) were made with a debit or credit card, and the percentage is growing, along with waistlines.

Researchers were intrigued, and devised a series of studies to look at various angles of the situation.

Before I get into the science of what was studied and the conclusions that were reached, I will tell you that this topic fascinated me. I decided to make my own hypothesis regarding the relationship between credit cards and obesity prior to reading the full study, just to see if I was correct.

I was not (I know, it surprised me, too, that I could ever be wrong!) but I won’t spoil it for you – think about the subject for a moment, and develop your own hypothesis. Let’s see if you got it right when we get to the end!

The research team had several points to cover in their multi-part study, but at the crux was the method of payment for food – cash or credit/debit cards. Using either form of card to pay for everything in life is becoming the rule rather than the exception, and cards are a somewhat painless way to pay. Paying with cash, on the other hand, can create more of a real “pain of payment” feeling.

Another aspect of consumer psychology that researchers factored in their study is that people tend to buy what are generally considered unhealthy foods such as cakes, pies, and cookies on impulse rather than pre-planned.

So, with the above information in mind, researchers asked: “Does how you pay make a difference in what you buy?” Will you automatically give in to the impulse to buy less healthy foods if you are using a credit card instead of cash? And if you use cash, is the reverse true: that you buy healthier foods and don’t give in to the unhealthy impulse buys?

And that leads us to the first part of the study.

Does How You Pay Impact What You Buy?

To study this part of the equation, researchers set up a 6-month observation of the grocery store buying habits of 1000 households. The data they collected had to do with the type of payment people used (card or cash) and the kind of food they purchased.

Researchers then tried to see if there is a relationship between these two. But in order to be able to objectively characterize the food as healthy/unhealthy and impulsive/non impulsive, researchers had one group of college students rate foods on a 1 to 9 scale of healthy to unhealthy, and a second group of college students rate foods as impulsive or not impulsive, also on a 1 to 9 scale.

When the responses were measured, the two separate groups had identified foods like cake, candy, and ice cream as both unhealthy and impulsive, while things like vegetables, whole grains, and fruits were ranked as not impulsive and as healthy.

The purchases made by the 1000 households were identified as being paid with cash, credit card or debit card, and then the contents of each shopping trip were analyzed using the scales of healthy/unhealthy and impulsive/planned that had already been determined.

Once the study was complete, researchers concluded that both debit and credit card purchases had a much higher percentage of “unhealthy/impulsive” foods, and that cash purchases had a much higher percentage of “healthy/planned” foods.

Interestingly, the time of the week when shopping is done also has an impact. When people go to the store during the week, they are more rushed and less organized, and have a higher rate of impulse purchasing and using credit and debit cards. On weekends when presumably they are less rushed, they plan their trip and list with more care and purchase less impulse items.

So now we have confirmation that there is indeed a relationship between buying unhealthy foods in an impulsive way and debit or credit cards as a from of payment. The fact that both types of cards led to the same levels of impulse and unhealthy purchases negates the idea that credit cards would produce that effect because it is a form delayed payment.

The money from debit card purchases comes out of your account right away, and is gone. Therefore, researchers conjectured that there is something else that can explain the relationship between the form of payment and the type of food people buy.

What was still very unclear is this: do people make those choices for impulse buys because they know they are using a credit or debit card before they ever start shopping? Or do they use a card after they’ve put a bunch of unhealthy impulse items in their cart? In other words, what causes what? Which comes first – the credit/debit card decision, or the donuts in the cart?

Does Paying With a Credit Card Automatically Mean You Will Buy “Diet Don’ts”?

To see if the use of credit cards causes unhealthy purchases researchers took 151 college students from Cornell University on a virtual, computer-based, food-shopping trip.

Half of them were told, before they started shopping, that they must pay with a credit card – and their shopping experience included seeing logos for the major credit cards to reinforce the concept.

The other half were told, before shopping, that they would have to pay in cash, there were no other payment options.

Then each participant was sent “shopping,” going page by page through pictures of 20 different foods that were clearly priced and titled. Their response time was tracked as well, and they had the option of putting something immediately into their cart or of just continuing to virtually browse. The menu consisted of 10 impulse/unhealthy items mixed with 10 healthy/planned items, and each item was viewed by itself on the screen.

When the purchases were analyzed, the results were interesting!

The group who knew they would be using credit cards had more of the impulse/unhealthy items, and took less time to decide on purchasing them. In contrast, the group who knew they would be paying cash had less of those impulse/unhealthy items. This finding gave strength to the idea that it is the form of payment that determines what kind of food buyers will purchase and not vice versa.

Researchers also noticed that both groups had the same amount of healthy/planned items! Payment form only impacted the diet-busting cart contents. Knowing they were using credit cards gave shoppers some kind of freedom to add things we all know cause us to gain more weight, but no matter what form of payment is decided on before the shopping starts, the same number of planned, healthier items will be purchased, suggesting that those purchases are less subject to emotion and impulse.

So what explains those findings? Why do people tend to buy more unhealthy food when they pay by card whereas they tend to focus on healthy food when they pay by cash? The theory among the researches was the idea of “pain of payment”, meaning that the physical act of taking money out of your wallet and handing it to someone else to make a purchase might really live up to that saying, “hits you in the wallet” by making the event more of an unpleasant sensation.

Does Paying in Cash Hurt?

To test the idea that paying in cash is actually more painful, the virtual shopping participants who paid cash responded in a combination of emoticon faces (yes, smiley to frowney!) and vocabulary words of negative feelings.

Sure enough, it hurts to fork over that cash! Participant responses confirmed that the act of paying in cash leaves much more room for regret of having spent the money. And who doesn’t regret spending money, taking away from their financial bottom line, when you know what you bought will be adding pounds to your, er, figurative bottom line?

If paying cash helps people maintain control because spending it is both memorable and painful, why does credit card use have a different effect?

Why Does Paying by Credit Card Hurt Less?

I’ll confess right now, this is the area of my own hypothesis that failed. I assumed that of course, people using credit cards don’t pay attention to how much they are even spending.

Why not supersize the fries and drink? Why not throw a few boxes of yummy looking cookies into your cart that aren’t on your grocery list but seem to be calling to you? You don’t need to know how much money you have to spend in cash – you are using plastic.


The participants who used credit cards were given a random recall quiz on items, and surprisingly they all knew the general prices and were very accurate in how much they were spending.

So the answer was not what I thought. Credit cards don’t insulate you from the amount you are spending, you are still relatively aware of the total cost of your shopping spree.

Why Can Paying With Cash be a Way to Control Fattening Impulse Spending?

Here’s where the study gets flattering! It turns out that it is a certain personality type that can leverage on the “pain of payment” effect of cash, and avoid giving in to impulse purchasing of foodie temptations that credit cards seem to facilitate.

What is the personality type you ask? Tightwads. That’s right – the scientific terms used were “Tightwads” and “Spendthrifts.” If you’ve never heard those terms before, in short it means this: a tightwad is much more particular about how and when they spend money for anything, whereas a spendthrift will buy just for gratifying the feeling of buying as the concept of sticking to a budget is not in their mindset.

So researchers used some control questions for the same participants in the virtual shopping study to determine who was a Tightwad, and who was a Spendthrift, to validate their theories.

And sure enough, that “pain of payment” idea was very real for the Tightwad group. They were able to control impulses that lead to unhealthy food purchases when they used cash. But when they used cards, the payment pain was numbed, and they tended to buy more things that will pack on the pounds.

Spendthrifts did not experience the “pain of payment” and so they purchased similar amounts of unhealthy foods regardless of the form of payment.

Why do credit cards seem to give us permission to buy impulsively, particularly those calorie-laden treats?

The researchers concluded that it might all come down to the perception in your mind. Using a credit card is sort of an emotionally uninvolved event. You hand over your card and it is charged, and even though you may be aware of the total cost, it is still not triggering emotional parts of your brain. So paying $150 by credit card doesn’t “feel” like paying that same $150 in cash.

Handling $150 in cash, watching it leave your hands and become someone else’s property makes it very real, and triggers more emotions and recall that you are spending the money. And that leads to more awareness of what you are spending the money on, and more possibility for regret – it all weaves together.

People tend to watch their dollars more closely when they are real dollars; and when they are real, they analyze what they are willing to spend them on more closely, leading to better impulse control.

So the entire study was thorough, and interesting – how did you do with your own hypothesis? No, don’t tell me, I’ll be upset if you were right all along.

But knowing all of this means what?

How Does Rhat all Relate to Weight Loss?

Impulse control. Sometimes you might think of it more as willpower, but it is in essence a very similar thing.

If you can control your shopping impulses, it strengthens your ability to control your eating impulses. We’ve all been there, you have your diet menu planned out for the day, you know the calories you plan to consume, and bam!

A slice of cheesecake comes out of nowhere and shoves itself into your mouth! Well, in reality you made the mistake of looking at the dessert counter and it led to a bad and diet-penalizing decision.

The same is true of shopping. If you can control the impulse urge to just toss a naughty little fattening something into the cart, then you are helping yourself not have it in the house at home to sabotage your weight loss efforts.

And the way you can control those impulses is to pay with cash. If you have any sort of “pain of payment” response, it will help. And that should probably be your policy for purchasing any sort of food, from the store or from a restaurant. Enable that pain, and pay cash – and help yourself lose weight in the process.

But I LIKE to Use Credit/Debit Cards!

The reality of the world is that using credit or debit cards is easy and often desirable for consumers. So how do you balance all you have learned about impulse buying and still use your handy plastic cards to go shopping?

Planning and awareness are key. And honesty. Even though we all like to think that being aware means we can beat the system, that is not generally the case.

Plan to use your credit or debit card for the things you know you need, the things that keep you healthy and keep your diet on track. Remember that planned, healthy purchases were not impacted by form of payment.

But also take some cash when you go shopping, and make it your rule to only pay cash when you spot a luscious chocolate cake as you pass by the bakery and it ends up in your cart. Let that pain of payment pinch you as you walk to the checkout stand.

Do you really want it? Then you have to hand over the cash for it. That fiendish chocolate cake may have conned its way into the cart, but it doesn’t mean the sting of having to pay cash can’t salvage the situation and make you put it back.

And when you do put it back? Victory for your diet!

About the author: Matthew Denos offers online codes for Weight Watchers and Medifast promotions, two weight loss meal replacement programs. He is a credit card user with a conscious to help consumers understand the psychology of payment. As a biologist he often writes about weight loss programs, diets and healthy eating.