Wednesday, April 08, 2009

Does Gastric bypass lengthen lifespan?

I received a comment on an old blog today and the misunderstandings in it are so great that I felt the need to answer this comment because many others may have the same misconceptions.

First point... the writer whose name is Jason, maintains that gastric bypass lengthens lifespan and uses the Swedish Obesity study to prove his point. Here is the quote:

The fact of the matter is that having gastric bypass has dramatically reduced deaths in patients who had the surgery versus patients who didn't! These are in PEER REVIEWED studies, with many patients. Swedish Obesity study on longevity

First of all, 10 years post op is not very long and keep in mind that only 13 percent of the surgical patients had had RNY (gastric bypass)... the rest were some kind of gastric banding. In gastric banding of any kind, there is no intestinal bypass as there is in gastric bypass and also, there is normal digestion in the stomach (although long term data on these patients shows a high percentage of paralysis of the stomach etc after 25 or 30 years). So even if the death rate WAS lower among weight loss surgery patients, this study would NOT prove that the gastric bypass increases longevity!

Second, there were not a significantly higher number of deaths in the controls (those who did not have weight loss surgery) than in the patients. (only 1.3 percent more deaths in the non surgical patients - has to be 2.0 or more to be significant according to statisticians.)

But let's take a closer look at the Swedish Obesity study because I'm going to prove that there was actually a MUCH lower mortality rate in the non surgical group in reality than in the surgical group.

This is because the study was not "randomized" meaning they picked and chose their participants. Here's why NOT randomizing the study makes it flawed as far as comparison between surgical and non surgical patients:

Randomization, where study participants are randomly selected and grouped by chance, is the most important way to help ensure that intervention and control groups are comparable (even in ways researchers may not have considered) and that the participants haven’t been hand-chosen to manipulate the findings towards a predetermined conclusion. Randomization prevents stacking the deck, so to speak. Source: Was This Really Proof that bariatric surgery saves lives

In this study, those chosen for the non surgical group had 25 percent higher incidence of heart disease than the surgical patients. They also had 6 percent more diabetes than the surgical patients and they averaged 18 months older. All of which can raise their risk factors.

And even with all of that, the difference in deaths in the surgical and non surgical group... were 1.3 percent more deaths in the non surgical group... with 25 percent more heart disease in the non surgical group, on the contrary, the non surgical patients were living LONGER than the surgical patients! That is, to be even with the surgical patients, the non surgical group with 25 percent more heart disease coming into the study, should have had 25 percent more deaths but in fact there was only 1.3 percent more deaths in the non surgical group.

So the Swedish Obesity study did not prove that weight loss surgery increases lifespan at all. On the contrary... (ibid)

The second comment Jason made was providing "proof" that calorie restriction prolongs lifespan.

Because we cannot obviously easily study humans for this, all the research "proving" calorie restriction has been done with rats and mice. These small rodents, though handy for study because of their short life span, don't really resemble humans in many ways.

But even among rat and mouse studies, the results are inconclusive or actually against calorie restriction prolonging life.

The study Jason provided was one done at Harvard Medical School. According to the article on this:

Dr. C. Ronald Kahn of the Joslin Diabetes Center at Harvard Medical School and colleagues genetically engineered a mouse that lacked a gene called fat-specific insulin receptor. This change limited the action of insulin on fat cells.

I don't think these genetically altered mice which lived a 30 percent shorter lifespan than the unaltered mice are very relevant to any humans. But if we are to compare, we should compare them to genetically or surgically altered humans i.e. like gastric bypass patients... will they, like the surgically/genetically altered mice, live 30 percent shorter lifespans than non surgically altered humans? One very large lady who refers to herself at "supersized" (over 500 lbs) tells me that she has outlived 48 of her friends who had weight loss surgery!

And other rat studies have found the opposite - i.e. that calorie restricted animals not only don't live as long as those who ate their fill but got sick faster.

The results of the one study which found that rats fed less calories lived longer than rats allowed their fill, have never been repeated. The other researchers who tried this study, found that rats fed less food, died earlier and got sick before dying. (ref: Stewart, Douglas: "Solving the Aging Puzzle" reference to the studies of Dr Stephen Austad, "Smithsonian Magazine", vol 28, no. 10 Jan 10, 1998)

About those studies which suggested calorie restricted rats lived longer, the author pointed out that the conditions were not normal... rats usually exercise to catch their food but the unrestricted rats were allowed as much food as they wanted and generally didn't exercise much during the day. "In other words", he concluded, "those studies only proved that overfed - under exercised rats did not live as long as calorie restricted rats"

Jason concludes by pointing out that:

Also, you severely downplay the health problems of obesity. True you can be obese and be healthy, but if you continue to be morbidly obese you will not be healthy for long. You WILL get diabetes. You WILL have heart problems. These are indisputable.

Sorry Jason but wrong again. Your facts are VERY disputable!

1. diabetes is hereditary and not a disease of obesity, and although it is thought by some scientists, that the eating habits which can cause obesity in some people may be a factor in some cases of diabetes, evidence for this has been inconclusive so far. Also to note: According to the ADA, 33 percent of type II diabetics have never been fat. I know personally 6 type II diabetics who are very slim. Including my father-in-law.

2. heart problems are also not a given for any group of people, not even those with high cholesterol! Many studies have suggested that heart attacks happen, equally, in people of all weights, sizes and cholesterol levels. For example, a gent who bragged to me that being 71, he weighed 150 lbs which is the same he weighed in High School, and that he walked several miles each day and had done that for years, a non smoker with no risk issues, had a major heart attack and needed a quadruple heart bypass. Yet a very obese relative who is 73 years old (BMI over 60) has no heart problems at all!

In conclusion, Jason, you are believing the ads for the diet industry in the media which often say very different things from what science and medicine has observed!

And about calorie restriction, what evidence we have, tends to suggest that unless it is done very carefully the person not restricting too drastically, not wasting any calories in junk food and fast food and taking lots of supplements, calorie restriction can be very unhealthy.

So much for what the media tells us. We should remember that the TV and the mass media is "for entertainment only" although truly their rants about overweight people are often far from being very entertaining.

The following page has some more of what science says about obesity:

Article: Fat Factoids


wriggles said...

we enrolled obese patients into the study who had sought surgery and compared them to a similar group who were undergoing conventional treatment during the same time frame.

I'd love to know what those treatments are.

Also, why compare them with these people, why not compare them to those who accept that they are fat and embrace life and see how those who've had weight loss surgery make out?


the surgery group had a higher risk of death from accidents, suicides and other causes not related to disease.

This does not recommend calorie restriction.

Elmo Dukat said...

This is a terrific myth-busting article! Thank you very much for taking the time to research a comment that many of us FA bloggers has had lobbed at us in one form or is greatly appreciated. :)

Illiterate Primates said...


Question: You write, "diabetes is hereditary and not a disease of obesity, and although it is thought by some scientists, that the eating habits which can cause obesity in some people may be a factor in some cases of diabetes, evidence for this has been inconclusive so far."

Does the example from the ADA that you cite include children? I'd be very much interested in reading some information about genetic causes vs. possible dietary causes for increases in Type II diabetes among children. If you could point me in the right direction.


Kristie said...

Great post. I'll be saving this one. I arrived in the Fatosphere by way of doing research for gastric bypass. I was depressed and desperate for a solution to my weight "problem." But what I read in my research scared the hell out of me, and I thought "No way," and decided to look up fat acceptance instead.

My life has gotten a whole lot saner, in all senses of the word, since I did.

GSO said...

heart problems are also not a given for any group of people, not even those with high cholesterol! Many studies have suggested that heart attacks happen, equally, in people of all weights, sizes and cholesterol levels.

But not gender. I know of 6 people in and around the edges of my life who suddenly dropped dead of heart attacks in their 40's - a few barely in their 40's. All were men. Only 1 was fat.

Harpy said...

Those calorie-restriction people actually eat more than most people on weight-loss diets though! If you go to their website and look up exactly what they eat, they don't eat "starvation" levels, they eay "a bit below normal" levels. Such as 2000 calories a day for an average man and 1700-1800 for an average woman. They are also extremely careful with nutrition and plan out all their food to ensure they are getting enough fat, protein, carbs and vitamins. They are emphatic that they are not about weight loss and starvation levels, just about *restriction*. Even though I personally don't think there's a lot of evidence to support their premise.

Whereas the average weight loss diet seems to be 1500 calories or less per day, often 1200, or even 800 for people on those liquid VLC diets.

professional daydreamer said...

calorie restriction does seem like it might improve longevity at extreme, precision-balanced levels. maybe. but this isn't what the billions of "it's undeniable that rats live longer...." articles are talking about.

~Melissa~ said...

I applaud your courage and honesty. I have been amazed about how "socially unacceptable" within the "gastric bypass community" that it is to say anything that could be perceived as negative toward the surgery.

I really wonder about the reasons for this? When I first starting looking into the surgery, even the year after it, I found tons of patient forums where I found a lot of comfort and support.

Now, I have been unable to find an online or community support group that will allow me to talk about "the sensitive subjects."

I want to personally thank you for your courage, candor and thought provoking post. (:

It helped me to feel that I am not *completely alone*--thank you for that. You have no idea how much I needed that.

If any1 knows the song, "Plump" by Hole, it is like my "Anthem Song" when it comes to my BDD and ED issues.

I've dreamed for years of different ways to come up with a ways to finally end the war between "me" and my body. I thought I was so close...I was so wrong.

Thanks again. Many blessings to you...


SueW said...

@Melissa, thanks for your kind words about my blog! There are support groups where you can share:





Both are places where long termers hang out and folks are free to speak candidly about WLS.

On Renewed Reflections you can be pretty candid and there is a very nice physician there who is available to answer questions and a supportive family.

Hugs to you,