A Formal Mathematical Investigation on the Validity of Kellogg's Glaze Claims
11 comments
·May 19, 2025Jabrov
It’s so sad that he just got a formulaic templated response. No one at Kellogg’s read, appreciated, or understood his humour.
ToValueFunfetti
Is "Hoping to restore your faith in us" really part of their form letter? It fits right in with the melodrama of the complaint, but I guess it's plausible that's what they always say.
troymc
Thank you for your comment. We appreciate you taking the time to share your thoughts.
Sniffnoy
All this manual calculation rather than just invoking the isoperimetric inequality? I mean, manual calculation isn't bad, if you want to do it also as an additional demonstration, but I think the isoperimetric inequality is worth a mention here!
gus_massa
The isoperimetric inequality is correct but too short. You need a longer proof with more equations and integrals to convince people.
dreghgh
The calculation is somewhat bogus since comparing a sphere and a torus with the same radius isn't really valid.
The author should either compare the surface areas of spheres and toroi with the same volume, or vice versa.
jrichardshaw
The author does indeed do that via their definition of the volume equivalent sphere radius r_s.
throwawaymaths
the claim is that it's the perfect shape for delivering glaze. assuming the interior of a torus does not contact the tongue, i submit that a torus wastes glaze, and the spherical shape is indeed perfect for delivery.
thesuitonym
That holds if we assume a frictionless digestive tract that performs no action on the cereal. Since the cereal will be crushed in the mouth, and all parts mushed together, it's reasonable to assume that the inner radius of the torus will touch the tongue, and what's more, the original claim was never about touch the tongue, but delivering more glaze in the same volume.
d--b
Well well well.
The donut vs donut hole debate is a trap, though, that even the most brilliant breakfast-savvy mathematician fall into.
Truth is, the original flat flakes had infinitely more glaze than either the donut hole or the donut, mathematically speaking.
But because Kelloggs compared the donut hole to the donut, people are easily tricked into settling for the most optimal of these two shapes, while completely ignoring that either shape is a massive step backward for any cereal lover out there.
This is blatant case of enshittification, Kellogg's. It's not Grrrrrrrrrrrrrrreat.
Spheres optimize for minimum sogginess. Kellogg could change the marketing angle without changing anything else to be correct.
Maybe. I haven’t done the math.