If you don't see the article's link to the research - https://www.pnas.org/doi/10.1073/pnas.2610287123 (yes, paywalled):
"Sugar rationing" is far too simplistic a description of the historical situation: https://en.wikipedia.org/wiki/Rationing_in_the_United_Kingdo...
I became immediately suspicious due to how complex the rationing schemes were.
Even the labels put on food like "margarine" aren't composed of what you'd normally expect, as they shifted to fish/whale oils due to availability.
Yeah the article doesn't mention how they account for all the other changes in people's diet, stress, environment and what not that happens during and after a war...