[f-]

Well, potato is one of the higher-calorie crops, and one pound contains around 350 calories. If you produce 3,120 lbs a year, that gives you about a million calories.

Now, let's assume a family of three - an average person needs around 2,000 kcal a day. That's 2,000 * 365 * 3, or around 2,200,000 kcal a year. So, you come quite a bit short. And that's on a good year; you're gonna have bad years, too.

Also a function of climate and soil. In the 19th century, settlers in the plains - Nebraska, Wyoming, etc - often couldn't make it work on 640 acres granted by the government. In contrast, there are eastern states where 20 acres would be more than enough.

(Farming in the West is now much more viable thanks to deep wells and mechanical irrigation, but that's a capital-intensive and resource-intensive approach that works best at a scale.)

[owenversteeg]

As pointed out downthread, you can indeed feed a family on one acre of land, and many people do actually do this.

The problem with your math is that it assumes the 3k lb yield from gp comment is for potatoes. Your crop yield depends a lot on the crop. Aparently you can get between 10-30 tons of potatoes per acre (that range is from beginner yields to expert) which would be 7-21 million calories per year. Plenty of room, then, to grow a number of other crops to eat a balanced diet.

[noir_lord]

Potatoes (if you eat the skin) and milk would theoretically be a balanced diet, supplemented with fish/occasional meat it was pretty much the Irish diet pre-potato famine.

Boring as hell after a while but it'd keep you alive.

[marzell]

During the famine, ireland produced way more for/potatoes then it required to feed it's people; they were just taxed to all hell.

Currently the US produces about twice the calories it requires. There are so many calories produced in forms of corn that the industry has made huge efforts to find new ways to use those calories (hfcs, ethanol, etc) in order to justify corn industry practices. The one liner is that we need to be able to feed the people, but obesity is at an all time high. People need more nutrition, not more calories.

[bwilli123]

Taxes were not the main contributory factor. "Ireland continued to export large quantities of food, primarily to Great Britain, during the blight. In cases such as livestock and butter, research suggests that exports may have actually increased during the Potato Famine. In 1847 alone, records indicate that commodities such as peas, beans, rabbits, fish and honey continued to be exported from Ireland, even as the Great Hunger ravaged the countryside." https://www.history.com/topics/immigration/irish-potato-fami...

[marzell]

Thanks for the clarification. I was actually meaning that they were being "taxed" in terms of food sent to the rest of the UK and not in terms of money. Even with the article you linked, it's not clear to me if "exports" means they were forced/taxed into sending food, or if they were willingly exporting food for money in lieu of eating... Or something else

[Spooky23]

Most Irish didn’t own property and were tenants. They didn’t “export” in lieu of eating, the English landlord exported the fruits of their labor and left them to starve. The English were very concerned about the Irish and their moral fiber, so they allowed them to persevere rather than get hooked to charity.

Others couldn’t pay their rent and were evicted. Millions of Irish didn’t flee to the slums of NYC, etc for kicks.

[bitdizzy]

> they were willingly exporting food for money in lieu of eating...

The "they" who decided to export were not the "they" who starved.

[CryptoPunk]

Ireland could not affordably import food, due to the Corn Laws.

[bane]

You can also get pretty complete with potatoes and oatmeal.

[ed25519FUUU]

You can maybe keep a small family alive on an acre, but not really feed long term. With such little space you need to dedicate nearly the entire plot to high caloric crops such as corn.

[FlyMoreRockets]

Each year, I grow an increasing amount of my food from less than an acre. Corn is not an efficient way to get calories in an organic system, it requires too much nitrogen. As others have mentioned, potatoes are much better. And beans/peas, which require achieve their nitrogen requirements via bacterial symbosis. If you really want to go efficient, grow Azolla. I once calculated that a person in a temperate climate could produce most of their nutritional requireents with a plot roughly 25 square meters. Azolla doubles in mass every 2-3 days in ideal conditions and draws everything but trace minerals from the atmosphere.

[three14]

Wikipedia seems to think that Azolla might be neurotoxic.

[FlyMoreRockets]

Yes and no. When stressed, it produces a neurotoxin.

[phkahler]

You math is wrong. Way wrong. 70lb per week is 10 pounds per day. I'm not sure its feasible for a person to eat that much. Maybe a family could. Maybe.

[nkurz]

It's frequently claimed that the average Irish male just prior to the potato famine ate well over 10 lbs of potatoes per day:

On a typical day in 1844, the average adult Irishman ate about 13 pounds of potatoes. At five potatoes to the pound, that’s 65 potatoes a day. The average for all men, women, and children was a more modest 9 pounds, or 45 potatoes.

https://slate.com/culture/2001/03/putting-all-your-potatoes-...

While there are people who doubt these figures, eating 10 lbs of potatoes per day is definitely more plausible than your comment indicates.

[Vrondi]

I have lived almost exclusively on potatoes at several points in my life, and there's just no way. I've watched a bulky manual laborer live almost exclusively on potatoes as well, and still not near 10 lbs a day.

[ponker]

This is kind of inconceivable to me. Is it because I’ve never done enough manual labor to eat 65 potatoes in a day? I can’t imagine even finding the time to cook and eat them.

[nkurz]

Arguing against the article, 1/5 lb is a pretty small potato. I just weighed a baseball sized potato I dug last week, and it was 7.5 oz (~1/2 lb, 200 g). So if you are picturing an average baked potato, it's probably only 30 potatoes per day. Which, granted, is still a lot.

Cooking time doesn't strike me as a problem. Boiling 30 potatoes does take somewhat longer than boiling 1 potato because the mass is greater, but it's pretty much boil and forget. Also, the boiling can probably be done by one of those women or children who are only eating 10 potatoes a day!

[3131s]

Probably because they weren't getting enough protein. It's easy to eat carbs forever if you have nothing else because you'll still feel intensely hungry without protein.

[silveroriole]

And if the calorie count upthread is right, that’s 4550 calories per day purely from potato, not counting any added butter, milk, beans, meat etc! I know people did more manual labour back then, but something seems wrong with that figure.

[vram22]

They may not have had access to much of (barely) higher end foods. I read somewhere that the English, who had conquered them, took away a lot of that sell / use in England, including beef.

Update: Found where I read it - Wikipedia:

[ The Celtic grazing lands of ... Ireland had been used to pasture cows for centuries. The British colonised ... the Irish, transforming much of their countryside into an extended grazing land to raise cattle for a hungry consumer market at home ... The British taste for beef had a devastating impact on the impoverished and disenfranchised people of ... Ireland ... pushed off the best pasture land and forced to farm smaller plots of marginal land, the Irish turned to the potato, a crop that could be grown abundantly in less favorable soil. Eventually, cows took over much of Ireland, leaving the native population virtually dependent on the potato for survival.[41] ]

That quote is from the section:

Potato dependency

in:

https://en.m.wikipedia.org/wiki/Great_Famine_(Ireland)

[vkou]

Pre-industrial agricultural labour is incredibly calory-intensive. 4000-6000 calories sounds about right for a day of agricultural work.

[peterwoerner]

I used to eat about that much a day when I was running twice a day (and I was losing weight while doing so). Michael Phelps was known for eating 10,000 calories a day.

[James_Henry]

His math is correct. Also, it's really easy math to verify. It's not surprising either. With the stated yields, you could feed a person. You'd need more for a family.

Of course, the yields could probably be improved in order to get the 140 or so lbs needed to feed a family of 3

[commiefornian]

The math is correct but the calorie count per pound potato is way off. It is 350 kcal not 350 cal.

[1propionyl]

In the US, 1 Calorie = 1 kcal elsewhere.

We refer to kilocalories with capital-C "Calorie". I don't know why.

[Groxx]

Probably because lower-c calories are meaninglessly small for like 99% of the population. It'd be like doing all your cooking in milligrams.

[bane]

When I used to work heavy manual labor I was definitely able to easily put down around 7-8 pounds of food per day. One of my coworkers was into weight lifting and estimated we were burning between 3,000-5,000 calories per day depending on the job.

10 lbs of potatoes is only 3,500 calories. Which, while far in excess of a "normal" sedentary lifestyle, is completely reasonable for people working heavy labor jobs if that's their primary food source.

[jjk166]

A typical person eats 3 to 5 lbs of food per day, and that generally includes some very calorie rich meats, dairy, nuts and/or processed foods - not exactly the stuff you'll get in your backyard. You might be able to feed a family on an acre of beans, but not on an acre of generic greens.

[grawprog]

A 10lb bag of potatoes isn't really that big. If you take one of those bags, split into thirds, as in three meals a day, that's a bit more than 3lbs per meal. If that's your only source of food, that doesn't seem entirely unreasonable.

[bane]

Potatoes have great yield in terms of calorie per unit harvested. Other plants, not so much. Think about how much weight you might throw away with a pumpkin or a watermelon.

I have some family members who devoted about an acre and a half to a mix of crops, squashes mostly as they grow the best where they live, and for a family of 5 still had to supplement their diet pretty significantly.

At the same time, they ate more healthily than they ever had before, and often had too much of certain crops that they gave away or sold at the local farmer's market.

[ed25519FUUU]

The magic valley in Idaho (named after its transformation) is a great example of this. Modern irrigation has turned what is naturally a high dessert climate into a food producing powerhouse.