Wednesday, December 9, 2015

Menu planner update - now with peanuts

{Update: values presented here are quite wrong thanks to a pair of errors recently discovered.}

 I spent a few hours cleaning up my menu spreadsheet. The biggest change is the addition of peanuts, oats and barley. I also changed the default settings to eliminate beef, pork and dairy in exchange for peanuts. Oats, it turns out, are a terrible choice for food production: an embarrassing 1.5 grams per m² per day and 1.1 kcal/m² per day. Sweet potatoes and squash achieve more than 90 times that calorie yield.

 The upshot is I have a much healthier reference diet, but it takes about 12.6m² (50.4m³) per person rather than a bit over 9m². That's still only a third of the usual assumed area, so I'll take it. One important consideration: I use 4-meter heights for my hydroponic areas. A 3-meter height requires about 16.7m² (50.1m³), while a 2.5-meter height requires about 22.6m² (56.5m³). Shorter spaces lead to inefficient packing of shelves, so improvements over my crude method could be made. These numbers could be verified using vertical farming techniques and facilities on Earth today. (I should write a grant proposal...)

 Peanuts have an incredible impact on a planned diet. They are high in protein, fiber and good fat. They have low mass yields (18 grams/m² per day) and calorie yields ( 107 kcal/m²/day), but the protein:fat:carb balance is overwhelmingly pointing in the right direction for a grain- and vegetable-heavy diet.
 Evidence shows that a diet that includes nuts (any kind, even peanuts which are technically legumes) improves heart health, lifespan and to a lesser extent quality of life overall. Using even a small amount (less than one serving per day) allowed me to eliminate beef and pork as protein sources, dramatically reducing saturated fat and improving overall macronutrient balance.
 On the other hand, due to low yields even a small amount of peanuts requires a large amount of space; about a third of the growing area would be peanuts and another fourth would be barley and wheat. I would like to see if peanuts can be trained for continuous production since they are indeterminate plants; this could significantly increase yields.
 For every 2kg of shelled peanuts, 1kg of shells is produced. These are ideal for hydroponic media (after crushing) for root crops like peanuts, carrots and potatoes, as well as for seed-starting plugs.

 Perhaps surprisingly, eliminating animal protein from the diet actually increases the area required to feed a person. This is because the animals are fed harvest waste; they may process their calories inefficiently, but they are calories that would otherwise have gone to waste. As a result I increased servings of eggs, chicken and fish somewhat to use the available biomass effectively. The overall efficiency was about 1 kg of edible meat per 5kg of biomass, with 1kg of biomass produced per 2kg of edible plant mass.

 It doesn't look a whole lot like my present diet. People would be eating a whopping ten to fourteen 100-gram servings of vegetables and leafy greens pretty much every day. Animal protein makes up about three servings per day, two of them as eggs. Grains make up about another three servings, while sweet potatoes and related starches weigh in around two servings per day. Overall the diet ranges between 1.75kg/day (children) and 2.38kg/day (men), lots of volume, lots of fiber. One can also see how much additional water is required: about 2.2L for men, 1.2L for women and 0.9L for children per day. It might become common to eat four meals per day, or at least the traditional three with frequent raw vegetable snacks.

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