A big part of why we all got this particular surgery over any of the others is the malabsorptive aspect. What I'd like to know is if anyone knows if there's an easy way to calculate approximately how many calories we actually absorb per... say, 100 calories.

Actually, a lot of literature says that modern bariatric surgery techniques don't really cause all that much malabsorption - unless of course you get the Duodenal switch. The caloric restriction is due to small pouch size and hormonal changes that turn off the appetite switch. We still need to take our vitamins and get tested, but I don't think the caloric malabsorption is all that much. I may be wrong, but that is what I have read.

I have the same result with the malabsorption as I did when I took alli so I'm definitely not absorbing fats

5 hours ago, NYCGAL000 said:

I have the same result with the malabsorption as I did when I took alli so I'm definitely not absorbing fats

i agree about the fat absorption. I definitely can tell I am not absorbing it all, so it begs the question of fat soluble vitamin absorption as well. However, I am pretty sure that if I ate sugar and carbs, I would absorb a great majority of the calories, because my weight would shoot right up.

56 minutes ago, AZhiker said:

i agree about the fat absorption. I definitely can tell I am not absorbing it all, so it begs the question of fat soluble Vitamin absorption as well. However, I am pretty sure that if I ate sugar and carbs, I would absorb a great majority of the calories, because my weight would shoot right up.

I don't think fat soluble vitamin deficiencies are a "thing" with gastric bypass. They ARE with the DS, though - those folks have to take supplements of those vitamins (A, E, etc)

"The internet" says the primary malabsorption is fats. And here is a really long article about it: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3571763/ and another https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5700383/

lol. I can't find a "figure" on what the fat malabsorption equates to in terms of calories, and I'm sure it is food-specific.

Found this article, though complicated.

https://academic.oup.com/ajcn/article/92/4/704/4597483

I do find it confusing trying to research the malabsorption aspect of RNY

“gastric bypass is known as a restrictive operation as it restricts both food intake and the amount of calories and nutrients the body absorbs.”

you’d think bypassing part of the small intestine would cause less absorption of calories.

yet I also see a quote which says:

”Mr James Ramus MD, FRCS - Consultant General, Upper GI and Bariatric Surgeon at Berkshire Independent Hospital in Reading comments on a common misunderstanding in modern Bariatric procedures. 'The gastric bypass is not meant to be a 'malabsorptive' procedure. i.e. you do not malabsorb calories. The bypass works partly as a restrictive procedure but perhaps the main benefits in the procedure are the changes in gut hormones that occur afterwards'

... but is that just one opinion? How much does anyone really understand how the procedure works? I mean they don’t really know the true mechanics of it. Especially since surgeons don’t seem to mention changes in things like how medications are absorbed Or utilized post op.

Another quote

“You had gastric bypass surgery. This surgery made your stomach smaller by closing off most of your stomach with staples. It changed the way your body handles the food you eat. You will eat less food, and your body will not absorb all the calories from the food you eat.”

im not sure there is a clear or simple answer out there

This is all confusing. If RNY doesn’t have the malabsorption component, why bother re-routing? Why take mega vitamins above those taken by vsg patients? I’ve googled, also, and it doesn’t make a lot of sense.

3 hours ago, pssk said:

This is all confusing. If RNY doesn’t have the malabsorption component, why bother re-routing? Why take mega Vitamins above those taken by vsg patients? I’ve googled, also, and it doesn’t make a lot of sense.

I don't think they really know for sure what all the surgery does - other than it works. It's definitely causing some sort of malabsorption because if you don't keep on top of your supplements, you can experience some serious deficiencies. I'm guessing these study results aren't consistent.

I don't think fat soluble vitamin deficiencies are a "thing" with gastric bypass. They ARE with the DS, though - those folks have to take supplements of those vitamins (A, E, etc)

I'm deficient in Vitamin A abd have to take extra over what is in my multivitamin, and I had bypass. Could just be my quirky body!

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I was thinking about this last night and what is the difference between RNY and duodenal switch? I actually researched both when I started this and all I could tell was that DS looks like a combination of a sleeve stomach with rerouting of RNY and gallbladder removal. I had my gallbladder out due to chronic inflammation and low function. I had RNY due to GERD. I understood RNY to be malabsorption and why we take all kinds of vitamins vs simply being sleeved. I don’t think it totally doesn't process fat. Otherwise fat soluble vitamins wouldn’t be effective. And carbs and sugars still have a impact.

The procedure bypasses a portion of the small intestine which means less of the food is absorbed and utilized by the body as calories and of course this means vitamins as well. So we supplement.

A lot of medicine is largely not understood and (I can’t think of the word) anecdotal? Based largely on personal accounts and not necessarily research. With bariatric surgery they get information from patients yet how much do they understand about the process of what happens in the body except that it works.

You have your risks but if it can battle obesity we accept these risks to have a tool to fight it. To say it’s not a malabsorption procedure when most doctors say it is, makes no sense to me. The sleeve procedure is a restrictive procedure but RNY is a combination of restriction and malabsorption bypassing part of the small intestine and alternating the body chemistry as well. How it’s altered exactly I don’t know. Except it alters the Ghrelin or hunger hormone. Ghrelin stimulates appetite while Leptin reduces appetite.