Eat your carrots and you will see in the dark. Every child hears it. It is the most successful piece of nutritional advice in the English-speaking world.

It was manufactured by the British Air Ministry to hide the invention of radar.

The true part first, because there is one. Carrots contain beta-carotene, which the body converts to vitamin A, which is required to produce rhodopsin — the pigment in the rod cells of your retina that makes low-light vision possible. Severe vitamin A deficiency causes night blindness and eventually permanent damage, and it remains a serious problem in parts of the world with limited dietary variety.

If you are deficient, correcting the deficiency will restore your night vision.

If you are not deficient, more carrots do nothing at all. The relationship plateaus. You cannot load beyond sufficiency and get superhuman eyes.

Now the propaganda.

During the Blitz, the RAF’s night fighters began shooting down German bombers in the dark at rates that demanded an explanation. The actual explanation was airborne interception radar, which Britain very much wanted to keep to itself.

So the Air Ministry fed the press a different story. British pilots were eating enormous quantities of carrots, and their night vision had become exceptional. John Cunningham, a genuinely successful night fighter pilot, was nicknamed “Cat’s Eyes” and became the public face of it.

The story ran. Civilians, under rationing and encouraged to grow their own food, planted and ate a great deal of carrots — carrots being one of the few things not rationed and easy to grow. The Ministry of Food leaned in with cartoon characters and recipes.

Historians differ on how much the Germans actually believed it, and the campaign was probably aimed at least as much at getting British civilians to eat a surplus vegetable during blackouts. But it lodged in the culture, and it never left.

Eighty years later, in a country with no rationing and no blackout, parents still tell children that carrots will help them see in the dark.

Carrots are good for you. Fiber, potassium, beta-carotene, actual nutrition. Eat them.

Just understand that the specific claim attached to them was invented by a government to conceal a military technology, worked better than anyone intended, and outlived the war by four generations.

That is the part I find worth remembering. Not that the claim is false. That we know exactly who made it up, and why, and it is still working.

You’re Doing It Wrong: Dump the Myths, Misconceptions, and Bad Advice You Believe is here: https://amzn.to/4cX2M4U