# Why prefer “99% fat free” to “1% fat”?

In my experience I tend to find low-fat products labelled as "99% fat free" much more often than the equivalent "1% fat".*

Why is this so? To me it seems counter-intuitive, because it reminds me of psychological pricing, where retailers price things slightly less than round numbers, partly so that consumers under-perceive the price. If that same effect is happening with the "99% fat free" labeling, consumers would over-perceive the amount of fat.

Is it because the psychological pricing phenomenon doesn't apply in this case for whatever reason? Perhaps other phenomena are at play? Or perhaps it's something that doesn't have to do with the numbers?

*: I can't find a source for this unfortunately, and I'm aware that in some circumstances the "1% fat" form is the norm, for example with low-fat milk.

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@jeromy Thanks for digging up consumer-psych. I think neuromarketing is a good buzzword to attract future visitors, though. Maybe I'm out of touch. – Chuck Sherrington Jun 28 '13 at 3:15
@chuck Whatever you like. I wasn't sure whether we should have a plain "marketing" tag, but I figured "consumer-psychology" could probably be used on just about any marketing question. – Jeromy Anglim Jun 28 '13 at 3:19
@JeromyAnglim Eh, I'd like to try it out, if it's just noise we can send it to the tag graveyard eventually. – Chuck Sherrington Jun 28 '13 at 3:21
An interesting thing about milk is that the "fat" is generally left implied, it's not "1% fat" milk, usually just "1% milk", and "whole" milk instead of 3% fat – Ben Brocka Jun 28 '13 at 14:53
There are a few studies here that specifically look at fat statements: Sanford, A. J., Fay, N., Stewart, A., & Moxey, L. (2002). Perspective in statements of quantity, with implications for consumer psychology. Psychological Science, 13(2), 130-134. – Jeromy Anglim Jun 30 '13 at 3:54

If that same effect is happening with the "99% fat free" labeling, consumers would over-perceive the amount of fat

I think you are misunderstanding the desired effect here. I don't see how "99% fat free" would lead to the impression that a product contains a lot of fat. My read is, "This is 99% fat free! That's really good!" as opposed to "1% fat" which more emphasizes the fact that fat is still present than the fact that it's not. Said another way, because 99 is a far higher number than 1, the brain is more positive about getting something that is really good (much higher fat-free percentage) than something that is slightly bad (very small fat percentage)

The other thing you may be overlooking is that "fat free" is a marketing term in and of itself. Products claim to be "fat free" in order to attract dieters / those looking to eat healthy. When comparing products people may choose the ones which have actively tried to reduce the amount of fat; this is what the "fat free" term is intended to convey. Compare that with milk, where "1% fat" really means "1% milkfat", a technical description of how rich the milk is (where "whole milk" is 3.25% - 4% milkfat typically), so the terminology is not used as a means to advertise that product as being better than the competition but rather as a means to identify the content of the product itself.

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This is just an elaboration on my comment that Sanford et al (2002) might be relevant to the question. If you don't have access Tony Sanford indicates that "To obtain a copy of any of these papers, please email."

The study reports three experiments.

In experiment 2 they found experimentally that there was a preference for the "% fat free" format.

Twenty-four hypothetical products were used to create items of the following type: Sundown Supermarkets are selling a new brand of yogurt that {contains 5%/ 25% fat}/{is 95%/75% fat free}. Is this a healthy product?/Is this an unhealthy product?

They found that

the percentage-fat-free format led to stronger endorsements of healthiness than the percentage-fat format. This is particularly evident at the higher fat level. The results also suggest that the percentage-fat-free statements may have reduced the impact of world knowledge. Thus, the intuition that the fat-free format is a better way to portray product healthiness is borne out.

They concluded that

Some of these references might be worth pursuing (i.e., a Google scholar search of articles that cite Sanford et al and use the word "fat").

### References

• Sanford, A. J., Fay, N., Stewart, A., & Moxey, L. (2002). Perspective in statements of quantity, with implications for consumer psychology. Psychological Science, 13(2), 130-134.
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Great references Jeromy! Your answer has a lot more science than mine :-) – Josh Gitlin Jun 30 '13 at 14:25

It's called "accentuate the positive, eliminate the negative." Or put another way, it's easier to portray the glass as "half full" rather than "half empty."

Especially when the ratio is not 50-50, but 99- to -1. That is "99 percent good" sounds a lot better than "1 percent bad."

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