We’re Eating More than We Know

I’d like to share an interesting study from INSEAD – changes in packaging and portions have huge impacts on consumption patterns.

Of course, it’s been common knowledge for ages. We all know that we’re eating a lot more than we should when we opt to have supersized meals (most famously popularized by the movie Super Size Me – but do we know exactly how much?

The study notes the fact that when size increases are distributed over three dimensions, they are much less noticeable. The picture below demonstrates how dramatic the difference in perception can be.


This interested me because we studied the concept of Just Noticeable Difference in Consumer Behavior a few weeks ago. The JND is the level at which someone is aware of a change – say, for example, from the palest pink to a SLIGHTLY darker shade – the point at which a consumer is aware that a change has been made. The concept applies to both downsizing and upsizing.

When companies are reducing product volume/quantity, they use this concept and gradually decrease the volume in small portions over time. For example, cutting down on what is supposedly a 1L milk tetrapak to 990 mL. The 10 mL difference is under the JND, so no one will notice it. However, when they are INCREASING the volume (in special offers, for example: “15% free!”) companies always ALWAYS make sure that the size of the increment is ABOVE the JND.

Given the current example, what this means is that companies often make larger changes than necessary when upsizing meals so that consumers can notice the difference and believe the ‘more value for money’ claim. It was recommended that they make ‘1-dimensional’ changes to minimize wastage.

The study also found that when one has to evaluate the caloric content of a MEAL as a whole, rather than its individual elements, predictions are usually wrong. Chandon asked professional dietitians to estimate the number of calories in a given standard meal – sandwich, beverage, and side – and most of them got it wrong when estimating full meal values. However, they were much more accurate when asked to evaluate all three components separately. The implication is that in the presence of more than one food element, estimates go awry when we subconsciously compensate. What’s even more dangerous is that the study showed that as meal sizes grew larger, the difference between actual and estimated calories grew even more!

The holistic estimate for the given ‘regular’ meal was 474 calories, but the real size was 480 calories. 6 calories is more or less negligible, fair enough.

But for the ‘extra-large’ meal, the variation was much greater – 1429 estimated calories versus an actual 1920. That’s 492 calories, or more than an extra meal!

Another finding (again, many people know this, but not enough in my opinion) was that most of the time, people miscalculate how much they’re actually eating. When they eat ‘healthier’ meals, they often give themselves small ‘treats’ which effectively cancel out the discipline. Chandon explains it best:

When eating food that is labeled ‘low fat’, “you think that you’re getting a free lunch in terms of calories. And so you’ll be more likely to order cookies and a full-calorie cola and as a result the paradox is that you’ve had a bigger lunch but you think you’ve had a smaller one.”

So friends – if you’re health conscious, stick to regular meals and fill yourself up with fruits or water if your appetite is not satiated. Your body will thank you for it.

PS. Not something from the study, but another piece of common sense that REALLY makes a difference – use smaller plates and spoons when eating. Your perceptions of how much you eat will change – you will begin eating less. Guaranteed.

Note: The study (download) was conducted by INSEAD Associate Professor Pierre Chandon and PhD student Nailya Ordabayeva.


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