Peer Reviewed Speculation About Labeling Added Sugars

Disclosing how much added sugar is in a food product is a good idea. Claiming it “will save millions of lives and billions of dollars” is not. Wandering away from the truth never is. But in Circulation last month, Yue Huang et al are bold to say they only have one worry about the precision of their forecasts of lives and money saved by labeling added sugars:

Our estimates may be conservative and underestimate the full health and economic impacts.

Facts, Estimates, and Forecasts

Oxford defines research as systematic investigation to establish facts and reach new conclusions. However, estimates – in isolation – are not facts. Estimates depend upon a set of assumptions that may or may not be true. Forecasts are even more distant from facts because they are estimates of outcomes from events that have not yet occured.

Modeling is a useful tool for estimating what might happen as a result of a new policy. Huang et al use microsimulation modeling for their forecasts and this technique can be quite valuable. However, caution is important when interpreting the output from such modeling. Molly Richardson and colleagues explain:

Models offer projections of effects, not demonstrations of effects. Such projections can be heavily dependent on the input parameters (that is, assumptions) of the model, and some published modeling activities are so heavy on assumptions of efficacy of the policies considered that the modeling can be seen as an instance of petitio principii.

Forecasts Are Inevitably Wrong

Yogi Berra was absolutely right. “It’s tough to make predictions, especially about the future.”

So the most important thing to remember about forecasts is that they are always wrong. Sometimes by a little. Sometimes by a lot. And that’s OK – so long as you don’t try to make a forecast sound like a fact.

Labeling added sugars is a good thing to do. People want the information. They find it helpful. As a bonus, it might even lead to better health and economic benefits.

However, predictions of saving billions of dollars and millions of lives should not be presented as facts. They are forecasts – a peer reviewed form of speculation. If advocates wander away from the truth, they will inevitably hurt the cause they’re trying to help.

Click here for the study in Circulation, here for the press release from the American Heart Association, and here for an example of how it was reported. For a more measured discussion of food health labeling, click here.

Tall Tales, photograph © Andrew / flickr

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June 3, 2019