Episode 544: The M&M Anomaly : Planet Money One hungry reporter goes on a quest to find out why his package of Peanut Butter M&M's weighs 0.06 ounces less than a package of Milk Chocolate M&M's.

Episode 544: The M&M Anomaly

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Hey, PLANET MONEY listeners. If you're looking for other cool things to check out, NPR has a bunch of great podcasts - one we think you would like, Ask Me Another. Their latest show has John Turturro answering a bunch of trivia questions about Christopher Walken while doing impressions of Christopher Walken. And then Jonathan Coulton does a cover of "Walkin' In Memphis" - get it? "Walkin' In Memphis?" One of my favorite karaoke songs of all time. You can find Ask Me Another on iTunes along with a bunch of other great NPR podcasts.


The other day, I went down to the lobby of our building here to get a snack, and I decided on M&Ms. But I could not decide which kind. So I bought two packs - one regular M&Ms, one peanut butter-filled M&Ms. And in the elevator back up to the office, you know, there's like never anything to do in the elevator. I actually started reading the labels on these packages, and I found something really strange. Here - I have one here. A pack of regular M&Ms weighs 1.69 ounces. A pack of peanut butter M&Ms slightly less - 1.63 ounces. They were the same price - a dollar each, but you get slightly less of the peanut butter M&Ms - 0.06 ounces less.

It's a tiny difference way down at the third decimal place. This is, of course, drove me crazy, so I started to look into it. That was a month ago. It turns out there is a whole weird world living down there at the third decimal place. When you pull on that little thread, lots of things start to unravel.

Hello and welcome to the Planet Money. I'm David Kestenbaum. Today, I'm going to take you down the M&M rabbit hole. I promise you'll never pop a piece of candy in your mouth and think about it the same way again. When I got back to my desk, I thought, you know, this is the kind of thing that someone probably has a whole blog post about. But I looked and there was nothing. I tried to look at the company's annual reports. Mars is the company that makes M&Ms, but there are no annual reports. Mars is a private company owned by the Mars family for generations, and they are incredibly secretive, like a real life Willy Wonka.

JOEL GLENN BRENNER: I'm sure that they were hoping no one like you would ever come along to notice such a small, tiny difference.

KESTENBAUM: This is Joel Glenn Brenner. She used to work for The Washington Post, and she wrote a book called "The Emperors Of Chocolate: Inside The Secret World Of Hershey And Mars." She says she's the only journalist the Mars company has ever really let in, so I asked her, am I crazy? Does this tiny little weight difference mean something? Is it just an accident? She said whatever's going on, it is no accident.

BRENNER: To even have that difference, I can promise you something that was angst written for the company. They don't want consumers to have a question like that to ask them.

KESTENBAUM: The Mars family basically never ever gives interviews, but I put in a request. And I kept digging trying to find out why one pack was slightly lighter than the other. I decided to track down a competitor. After all, who studies M&Ms more closely than a rival company? And I found Bill Edwards. Bill used to work for one of Mars' main rivals, a company called Rowntree's. Rowntree's developed the British candy called Smarties which, I had to say, are a lot like M&Ms.

BILL EDWARDS: You should appreciate actually that surely the confectionary industry is incredibly secretive. I mean, more secrets have escaped from the places where they make nuclear weapons, and they've never escaped from the places - from the major to confectionary firms.

KESTENBAUM: Bill is a chemist by training. He spent a lot of time trying to reverse engineer competitors' products. He told me that he and his colleagues once did an extensive scientific analysis of Milky Way bars to try to figure out why they had a double layer of chocolate coating. When you're doing something like that, he says, even little things like the weight of a package can be a clue. In some industries, companies spell out stuff like that in their patent applications. But candy companies don't mess with patents, he says, consider, for instance, the Kit-Kat which his old employer invented.

EDWARDS: You know, I mean, been making Kit-Kats since about 1934. And there are certain things in that process, certainly, that would have been patentable. But if it had been patented, it would have been in the public domain in the 1950s. They're still secret.

KESTENBAUM: Do you know how Kit-Kats are made?

EDWARDS: I do know how Kit-Kats are made, yes.



KESTENBAUM: Can you tell me?

EDWARDS: I couldn't do that. No, no, it's a secret.

KESTENBAUM: (Laughter). If I knew the secret would I think, oh, that's so cool?

EDWARDS: The old Rowntree company used to have a rule that there had to be at least one difficult stage in each product. There are about half a dozen difficult ones in making the Kit-Kat.

KESTENBAUM: Bill had a theory about the M&M puzzle. It's possible, he said, that peanut butter M&Ms are more expensive to make. If that's true, you'd want to put less of them in the package as a way to keep the profit margin the same.

EDWARDS: You're not going to grow - you're not going to do wonders for your business if you bring out a new product that is less profitable than your existing ones.

KESTENBAUM: Oh, so if like if you had M&Ms that were out there, there's a certain profit margin, you're going to introduce peanut butter M&Ms, you would never want to introduce that where you're going to make less money on each pack?

EDWARDS: No, no, no.

KESTENBAUM: I like this explanation. It's actually what my sister who's an MBA told me she thought was going on also. It made sense because imagine you introduce your exciting new peanut butter-filled M&Ms and people like them so much that they stop buying the original milk chocolate M&Ms, and they switch to the peanut butter ones. If you're making less money per pack on the peanut butter ones, congratulations, your wonderful new product just lost you money. Of course, Mars could keep the profit margin the same by just charging a little more than a dollar for the peanut butter M&Ms instead of putting less in the package. But John Gourville, professor of marketing at Harvard, says that is a really dumb idea, and companies almost never do that.

JOHN GOURVILLE: Imagine (laughter) if you did this with something like yogurt, where, you know, the peach yogurt is 79 cents, the blueberry yogurt is 89 cents and the strawberry yogurt is 99 cents. You now are getting people thinking, geez, how much do I like strawberry relative to peach?

KESTENBAUM: (Laughter).

GOURVILLE: Is it worth 20 cents? It's just - it's a layer of complexity that manufacturers would prefer not to get into. They want to make the decision-making simple.

KESTENBAUM: Companies would rather adjust the amount of stuff in each package, so they can keep everything the same price. So that when you go to buy, say, M&Ms, you're not doing math in your head comparing prices. You're just going, yum, M&Ms. They're all a dollar. Which one do I want? Even though the weights, if you look closely - they're slightly different. This was a beautiful theory. It explained everything - the dollar price, the lighter peanut butter M&M pack.

It turns out, unfortunately, there's a problem with it. In order for it to be right, peanut butter M&Ms have to be more expensive to make. Remember that's why you get less in a package. But Bill Edwards the chemist told me that upon reflection, he's pretty sure peanut butter is cheaper than chocolate. I did some checking at bulk suppliers, and that seems to be right. So much for the economic explanation. Maybe there was a scientific one.

Is it OK if I buy a lot of M&Ms?

I went back down to the little store in the lobby of our building, and I bought what scientists would call a statistically significant sample size.

Ten of these, should be 10 of these. I took the M&Ms up to Columbia University to a guy who had a really, really precise scale - Sanat Kumar. He's chair of the chemical engineering department.

SANAT KUMAR: You know, this is a tenth of a gram, and this is going to tenth of a milligram, so a thousand times smaller than what you're looking for.

KESTENBAUM: This is a thousand times more accurate than we need?

KUMAR: That's right. (Laughter) Talk about a little bit of an overkill, right? So let's zero that...

KESTENBAUM: Sanat had a different theory. What if, he said, each bag gets filled by a machine that drops a precise number of M&Ms in each bag - the same number in each bag? Then if the peanut butter M&Ms turn out to be a little bit lighter, that could explain why the package came out lighter. So we started counting.

KUMAR: Ten, 12, 14, 16...

KESTENBAUM: One bag had 27, another had 28. Twenty-seven. OK - so 27, 28. So they're not keeping the number constant.

KUMAR: It's all over the map. This is truly amazing. I have no idea what they're doing.

KESTENBAUM: Another beautiful theory destroyed by data. We did discover something weird, though, that would turn out to be a critical clue, something that somehow I had never realized when I was shoving these things in my mouth. And it's that the peanut butter M&Ms and the regular M&Ms are totally different species. The original milk chocolate Eminem's are these small, very precise candies with very precise weights. The peanut butter M&Ms by comparison are monsters, lumpier, larger. We measured with the fancy scale, and the larger size turns out to be key to the whole puzzle. I eventually got an email back from the Mars company declining our interview request, but it did include a statement which I think explains the whole mystery. It has nothing to do with the price of peanuts, compared to cocoa or the number of M&Ms that get dropped into little bags.

It was a different number that mattered - calories. The statement said that for health and nutrition reasons, all Mars products are designed to be 250 calories or less per portion. Sanat and I did the math, and it turns out because the peanut butter-filled M&Ms are so big, if you added just one more of them to these little packages, it would push the calorie count over 250. This more seems to be saying is why the package weighs a little bit less. I ran this by Joel Glenn Brenner, who wrote the book on Mars and Hershey. The only outsider who'd been allowed in.

Do you believe this? Does that sound right to you?

BRENNER: Absolutely.

KESTENBAUM: She says the 250-calorie thing - that's become a kind of maximum, a line that the candy companies don't want to cross.

BRENNER: An acceptable snack calorie size.

KESTENBAUM: Anything larger than that, you're talking like hamburger territory or...

BRENNER: Yeah. You're talking - that's just too big. That's a meal. That's not a snack.

KESTENBAUM: There was one other little thing that still bugged me, though. Why were the peanut butter M&Ms so big? Joel had an answer for this, too. The size, she thinks, has been a longstanding problem for Mars. Mars' big breakthrough was that the filling for its peanut butter M&Ms was actual peanut butter. Reese's Pieces, she says, actually contain something called penuche. It's peanut meal, which is easier to work with and coat. True peanut butter, she says, is softer, lumpier and harder to work with.

BRENNER: I am certain that they did a considerable amount of engineering research to see if there was any way possible to reduce the overall size of that peanut butter M&M so they could avoid this dilemma.

KESTENBAUM: They could avoid me calling them.

BRENNER: Absolutely. But they must have hit some wall where it just simply wasn't possible.

KESTENBAUM: They couldn't get them any smaller.

BRENNER: They couldn't get them any smaller.

KESTENBAUM: I sent Mars a follow up email asking why the peanut butter M&Ms were so much larger than the regular ones. The next day I got a one sentence answer, quote, "because of proprietary reasons, we are unable to elaborate on the size of peanut butter M&Ms."


69 BOYZ: (Singing) Cotton candy, sweetie, go. Let me see the tootsee roll.

KESTENBAUM: Let us know what you think. You can send us email planetmoney@npr.org. If you haven't seen it, you should check out the drone video that our colleague Steve Henn did. It was inspired by the show we just had about who owns the air. The video is of Steve talking in his backyard. It's shot by a drone that goes higher and higher into the sky, up to the very edge of legal drone airspace. You can find it at npr.org/money.

If you're looking for other things to listen to, NPR recommends Ask Me Another. You can find it on iTunes. Our show today was produced by Phia Bennen. Special thanks to Jennifer Pana and Jennifer Xiong, post-doc and student at Columbia University who helped with weighing all those M&Ms. I'm David Kestenbaum. Thanks for listening.


69 BOYZ: (Singing) Cotton candy, sweetie, go. Let me see the tootsee roll. I don't know what you've been told. It ain't the butterfly. It's the tootsee roll. A brand new dance so grab a partner and get on the dance floor and work them hips a little bit, then do that dip a little bit. Oh yeah, you got it...

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