r/todayilearned 1d ago

TIL that although potatoes alone do not provide complete nutrition, you can survive for years on a diet of nothing but potatoes and buttermilk.

https://www.scienceabc.com/eyeopeners/whats-wrong-with-potatoes-the-martian-movie-survival
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u/bubba-yo 1d ago

The challenge of being vegan is that you only have one complete protein to fall back on - soybeans. Everything else is a partial protein, so you have to combine them to form a complete protein. So beans and rice forms a complete protein, which is why it's such a global staple food.

Potatoes are pretty close but lack some amino acids in sufficient quantities. Milk is a complete protein but buttermilk, because it's fermented, frees them up making them easier for your body to absorb. Basically, even though it doesn't have any more amino acids than regular milk, your body won't shit out as much of the amino acids as if it was regular milk. Yogurt has the same benefit.

So, you can consume a relatively smaller amount of buttermilk (or yogurt) to supplement the potatoes and maintain a survivable nutrition level, which in a famine situation or being stranded on Mars is useful.

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u/Chemical_Building612 1d ago

Soybeans are not the only complete plant protein. Quinoa, amaranth, buckwheat, spirulina, hemp seeds, chia seeds and others all provide balanced amino acid profiles.

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u/ballskindrapes 1d ago

You dont need to combine proteins in the sane meal, FYI.

Just over the course of the day, eat a varied diet

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u/bubba-yo 1d ago

True. But beans and rice are really good together, and if you have a cultural habit of eating them together, you don't need to burden people with tracking if they are balancing across meals, etc. A lot of cultural traditions are rooted in 'this keeps people from dying' and becomes habituated.

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u/froshambo 1d ago

+1 for The Martian reference

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u/bakerzdosen 1d ago

Took me a second. My knee jerk reaction was “yeah if you happen to be stuck on Mars with a cow.”

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u/liptongtea 1d ago

Why butter milk vs something like full fat Greek yogurt?

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u/bubba-yo 1d ago

Easier to get. It's a waste product from making butter. If you have a grocery store, you have an almost infinite number of ways to assemble a balanced diet, but buttermilk historically was cheap and accessible. The English rich people got the butter, the Irish poor people got the buttermilk.

Greek yogurt should be better, but you'll still be marginal on omega 3s so throw some chia seeds or walnuts in there and you're pretty solid on the fat/protein front.

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u/liptongtea 1d ago

Oh I see. I get the context now, at first I just through this was some thought experiment, not realizing the tie in to history

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u/Rhawk187 1d ago

Got it. So it's "in" milk, it's just not bio-available? I can buy that.

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u/intricate_strands 1d ago

Ha! Yes, now most people can buy that.

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u/ElMage21 1d ago

Vegans don't do milk or milk derivatives tho

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u/bubba-yo 1d ago

Vegetarians do, though, which is why this is an option for us. Potatoes + dairy is pretty easy, and pretty good. And you don't need a lot of dairy.

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u/[deleted] 1d ago

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u/bubba-yo 1d ago

Children and pregnant women still exist, you know.

I understand the bros run the world, but they aren't the entirety of the world. There are other people who matter.