Why are Jerusalem artichokes low carb and a good source of calories?

Some people recommend planting Jerusalem artichokes as a low maintenance calorie crop, containing as many calories per pound as potatoes, while being easier to grow.

Others recommend them as food for dieters and diabetics, as they are not actually digestible.

How can these statements both be true?

Technically, they are not low carb, but low starch. Most of the food plants that humans like convert glucose, a sugar, into starch (by polymerization) and then in our gut, the starch is slowly broken down to glucose to provide our energy needs. But there is another class of plants that convert a different sugar, fructose, into inulin as their storage carbohydrate. These plants include Jerusalem artichokes and chicory, among others.

Human digestive systems, while they can process inulin, are not tuned up to do so efficiently. Foods that are high in inulin are good for diabetics because there is no glucose rush from all that starch breaking down. But if all that inulin passes through the digestive system into the lower intestine without much breakdown, once it hits the bacteria there, they may cause a strong and powerful wind.

I have this hypothesis, and I haven't seen much research into it, that if you eat high inulin foods, your digestive system will adapt to high inulin foods. The few times that I have eaten them, they did not particularly bother me. But then again I eat a lot of sauerkraut, yogurt, buttermilk and other fermented foods, so I was probably well prepared for it.

Apparently, slow-cooking can turn much of the inulin into fructose. This is the method recommended by Sally Fallon in Nourishing Traditions to prevent digestive upset, too.

Also, from http://paleohacks.com/questions/27639/converting-inulin-to-fructose-through-slow-cooking.html :

"The most dramatic reductions in inulin content, however, are obtained by slow cooking. Another inulin-rich plant, the camas lily (camassia spp.), was traditionally pit cooked by Native Americans. This involved burying the camas lily bulbs in a pit and covering them with dry wood and stones and, once the fire had been established, earth and grass. The food was cooked for 12 h to 36 h. This method was also possibly used for Jerasalem artichoke tubers, over a 12 h period. Cooking by this method eventually turns all the inulin to fructose, leaving a sweet and soft textured food." from Biology and Chemistry of Jerusalem Artichoke: helianthus tuberosus L. by Stanley Key and Stephen Nottingham, page. 108.

I converted inulin to sugars by harvesting in february and not october-december. Nobody here has many problems anymore. The first year, harvesting in october, was tragic. If you don't have problems with rats or mice getting to them, you can do that. I even had rats eating the compost on top and I still am going to have a huge crop this year.
William

I am ashamed to admit, I cannot help snickering like a 6th grade boy when you all describe the "tragic" incidence of "powerful wind." My favorite line of Nourishing Traditions is the description from 1617 of "a filthy, loathsome, stinking wind within the body." They are like nature's Sugar Free Gummy Bears.

Inulin is prebiotic - thus feed the healthy bacteria in your gut

Is there anyone here who can attest to their digestive systems becoming attuned to sunchokes? I grew a great deal of them in the garden this year and foresee months of meals. At first I saw a great bounty, however, after the first few meals, I am thinking I will have to plan to eat these on days in which I don't wish to socialize, or work, or go out in permies.... I have not tried to slow cook them as I imagine them being a very mushy mess after 12+ hours of cooking, and it seems like a great deal of energy to expend. It wouldn't be a problem for someone to cook on top of a wood stove because in winter it would be emitting heat regardless of whether you are cooking or not.

Is anyone aware of specific bacteria needed in the gut to break these down without creating copious amounts of gas and is there any way I can supplement these bacteria to help build populations in my gut? John Elliot mentioned he thinks that he is immune because of eating a lot of fermented food? I tried sauerkraut as a kid and was repulsed by the taste. The only other fermented food I eat is the occasional Greek yogurt.

Should I just "power through it" and eat fartichokes until I'm no longer affected? If it will take only a week or so to adjust, I'm ok with it, but much more than that and I will probably not have many friends left or coworkers who are willing to work near me. Luckily my kids find it amusing, and my wife took vows at our wedding: "in sickness and health..."

I would advise eating a small amount every day, then when you notice less gas, try a bit more.

You are building up a population of inulin digesting bacteria, ones that don't make lots of CO2 (and other things).

Do you have any suggestions about how best to prepare them while building up these bacteria? Or would a small raw tuber a day be best?

Well, raw is going to have the most inulin. Slow cooked the least. If you're taking a small amount every day, raw is probably the easiest and fastest.

This winter I am going to put the sunchokes into my sauerkraut. I can slice them and therefore not eat huge quantities at a time. In addition, the fermentation will partially digest them, and I will be able to use the enzymes and probiotics in the sauerkraut to help me pass a more gentle wind.
John S
PDX OR

Thank you Julia. I will try a daily bite or two. Even if it is as John Saltveit says, a "more gentle wind", I will be satisfied.

I have never before had a food that had such an immediate and predictable response on the gut. On the bright side, this last weekend my wife's midwife suggested that she eat something that causes a lot of movement and action in the gut to try and trigger labor to get our overdue baby out. Immediately we both said "fartichokes".

If you plan on using them for people-food, eat small quantities for their taste and texture. If you want to eat them a a sizable source of calories, I put them in a steamer basket, then set the basket in a slow cooker, always keeping some water in it, for ~ 24 hours. They come out a dark caramel color and taste sweet. No gas from eating them cooked that way.

But honestly, sweet potatoes are easier to cook, taste better, and are more flexible. If you want something with inulin(for its gut bacterial benefits) get some jicama instead. Feed your sunchokes to your pigs.

Gilbert Fritz wrote:Some people recommend planting Jerusalem artichokes as a low maintenance calorie crop, containing as many calories per pound as potatoes, while being easier to grow.

Others recommend them as food for dieters and diabetics, as they are not actually digestible.

How can these statements both be true?

As someone else mentioned: It's the innulin.
I grow these little gems and have to give some away!
Here are a few references you may want to read.

http://charodeizi-topinambur.com/topinambur-and-diabetes/?lang=en
https://www.nutrition-and-you.com/jerusalem-artichoke.html

or the ever popular Wiki:
https://en.wikipedia.org/wiki/Jerusalem_artichoke