When you're trying to find a suitable monodiet, you're looking to meet certain nutritional needs, but there are few foods that can meet all nutritional needs. Maybe there's some you can draw down reserves of for a time. Maybe there's some that your body can make alternatives for, or synthesize through a costly path, or even just sort of blunder along without. Maybe you even reject the idea of certain nutrients being essential from diet as a matter of principle, or want to find an island of stability outside of mainstream nutrition.
We know that people do surprisingly well on potatoes, and I've written about trying to find potato diet monodiet (and duodiet) alternatives before, but how do you know whether something is functionally equivalent to potatoes in terms of its suitability for a monodiet? Potatoes are quite high in some things (potassium) and quite low in some things; one doesn't expect to get EPA/DHA from potatoes, say.
There are worse things to consider. What if you can find a diet which could provide the same essential nutrient profile, but only if a vastly larger quantity of energy were to be consumed? What if the diet meets all your needs, except that it comes in the form of 45kg of clam juice?
So you have to approximate at some point, and you are limited to the things you can measure, the things you choose to care about, and so on.
I want to find monodiets that approximately match the nutrient profile of a potato when eaten to around 2000 kilocalories. Why? Because you have to start somewhere. I'll talk about potatoes from here on in terms of 2000 kilocalories of potato. Because it's the dataset I know best, I'll be working consistently with the Canadian Nutrient File, which is a wonderful and wonderfully inadequate resource. It keeps me humble about my conclusions.
So, what nutrients shall we care about? We don't want to find things that are exactly the same as a potato, because that's just a potato. We probably want to treat some characteristics of potato as minimums, some as maximums, and just ignore others despite allowing for the possibility that they are consequential.
Let's say part of what makes potatoes work is something about their macronutrient profile. They have something like 50g of protein, 2g of fat, and 454g of carbohydrate (a pound, one might notice.) So I'd say that when we're looking for something comparable to potatoes, we want something with at least 40g of protein, but not more than 75g, less than 5g of fat, and no limit on carbohydrates. Seem like a reasonable start? Let's assume that the breakdown of the carbohydrate content isn't significant, too.
Potatoes have reasonable amounts of calcium (311mg), iron (20mg), magnesium (600mg), phosphorus (1500mg), sodium (155mg), zinc (8mg), copper (2.81mg), manganese (4mg), and selenium (60mg). We know they have heroic quantities of potassium (11g, as in 11000mg!)
I'm happy to say that we need round numbers of those as minimums, and no upper limits for the moment. I'll just round them all down to nice numbers, and not bother rehearsing all of them here. We want to find things roughly like potatoes, we're not looking for things that are better than potatoes, nor to experiment with potential alternative islands of stability. I don't think we need to treat any of those as limits, but there's a few where that could be sensible.
Let's assume we don't care about fatty acid composition because we're mostly limiting fats in looking for potato analogues. More problematically, I'd prefer to ignore amino acid profile for two reasons: (1) the ranges are hard to pin down; and (2) the data are especially unhelpful in missing these for a lot of foods.
We then have the problem of Vitamin A, retinol, carotenes, etc. I'm slightly reluctant to give them consideration, probably more out of laziness than anything else, so let's allow my laziness to flourish and ignore them. (I'm tempted to set upper limits, but, again, laziness.) I don't know any betaine stans, but it's a little tempting to include it as a carnitine precursor, but let's not. Choline, on the other hand, is relatively available in potatoes (315mg), so let's set a really modest need (200mg).
Folate is a really important one that I'm going to completely neglect again because of data problems. There are a lot of different ways folate can be computed and tracked, and their use is inconsistent, and so we would really need to have a more complex set of rules. This is a major problem. Luckily, none of this is nutritional advice, this is not dietary advice, this is definitely not medical advice. Data problems alone should be sufficient to be off-putting.
I will let us entertain the need for Vitamin C, though, because potatoes come in surprisingly strong (510mg), and we'll look for at least 400mg. We'll ignore the modest amount of Vitamin E, as it's not enough to be sufficient.
That leaves the B vitamins, and I am constantly at war with the B vitamins. Potatoes hit with 35mg of total niacin equivalent (we'll look for 30mg), 7mg of pantothenic acid (we'll look for 5mg), and 7mg of B6 (we'll look for 5mg).
With that, we've attended to or roundly ignored all of the nutrients in the Canadian Nutrient File for "Potato, flesh and skin, raw". Sounds delicious, doesn't it?
Clam juice comes in hard, with a mere 12.5kg being deficient only in Vitamin C and Vitamin B6, and not very deficient at that. Of course, that gets you all of 250 kilocalories, and I think we can do better. Honestly, I am starting to wonder if anyone sells dehydrated clam juice, because it seems like a great way to get a lot of things without having to think too hard.
Let's take a firm pragmatic turn and say that 3kg is the upper limit of mass for a monodiet in a day. It's tough to eat even that much, and we're not leaving ourselves a lot of room on the low end of our requirements, so if someone can't eat up to these levels, we have a problem.
This gives us two real contenders which are not just more potatoes, one of which I'm not even sure what it is. The first is "Balsam-pear (bitter gourd, bitter melon), leafy tips, boiled, drained" (and also a variant with salt), and while I like bitter melon a lot, I'm not actually sure what the leafy tips are. If that's the leaves, that's very interesting, but outside of when I grew bitter melon myself, and when I used to have access to a really fantastic small produce store, I haven't seen bitter melon leaves very often, so this is probably not viable. Still, at 600 kilocalories and a mere 1.8kg of drained leaves, this only comes up short on selenium (16mg, less than 40mg) and pantothenic acid (1mg, less than 5mg.)
Pantothenic acid, so-named because it's found in everything, is consistently slightly elusive when I go trying to craft monodiets. Go figure.
The other real contender is okra, which at 800 kilocalories and about 2.5kg of raw mass (the same as potatoes for 2000 kilocalories), comes up short on potassium (7g, less than 10g) and selenium (17mg, less than 40mg). Potatoes are really amazing in their potassium content, and selenium is another annoyingly scarce nutrient in sufficient quantity.
Something you may notice is that these are both fairly low energy monodiets. This is what nudges me more and more towards duodiets, so that you can have some food you eat for micronutrient needs, and another food you eat for energy needs. This seems like a pretty reasonable way to go, but given that potatoes provide both nutrients and energy in levels we find appealing, and with a density that more-or-less works, this is a bit daunting. It would be tough to eat 2.5kg of okra and then to have to top it off with many more calories, although a large quantity of okra fried in ghee, or cooked in a curry with a lot of fat, doesn't sound so bad to me.
Let's take one last crack at the thing, and knock out pantothenic acid and selenium. Can we do better?
You're going to hate me.
This only gives us one good potato alternative, which has no failures with those constraints. At 2000 kilocalories, you can eat around 2.2kg of cooked sweet potato flesh. Yep, you could maybe substitute sweet potatoes for potatoes.
It's kind of amazing what a singular thing the potato is in this particular island of stability, being high carbohydrate, overall energy-dense, low in fat, and low-moderate in protein, while providing useful amounts of some pretty desirable nutrients, even if you leave out whatever's going on with the very high potassium.
There are a lot of other good ways to formulate monodiets, especially if you're willing to make choices about meeting some needs entirely from supplements. There are a lot of things that all of our diets are deficient in, and other things that I know we just don't have great data on in this one dataset. I've played with a few others, and I dream of building a multi-source suite of tools that can aggregate all of this data in meaningful ways, but the Canadian Nutrient File represents an easily digested starting point, and prepares you for the kinds of problems you have with drawing conclusions from the data available to you.
I suppose, too, it helps one to appreciate the wonder of the humble potato.
No comments:
Post a Comment