Summary: Hearing that some women choose to avoid meat [sort of] as part of a way to lose weight does not surprise me, but when certain facts and statistics are reported in a loose way, I feel the need to say something. When an article describes 52% as a great majority, I dissect what the actual study said, where it went wrong, and how the reporting of it went very wrong. Because that's the kind of thing I do.
BLOT: (01 Aug 2012 - 12:24:44 PM)
Study tests links between eating disorders and vegetarian diets. "News report" adds to the confusion over the statistics and findings. I dissect...
At first glance, an articled tittled "Great Majority of Women with Eating Disorders are Vegetarians" sounds like a definite statement. Then you find out that it was posted by the user "Eating Disorders Online" and its primary source is an article on eatingordersonline.com and that is sourced to an article on Examiner.com: "Vegetarianism five and a half times more likely with an active eating disorder". In the former article, you might be let down to find out that the so-called "great majority" was only 52%, which surely is much more likely to be a "slight majority" at best, but at least the "five and a half times more likely" of the second article sounds a bit more damning. Partially because we read such things wrong,1 and collude "what percentage of X is Y?" as being an equivalent exchange with "what percentage of Y is X?".2 Saying that a number of people with eating disorders (Ped) has experimented with vegetarianism (Pv) is not the same as saying that a number of Pv has experimented with eating disorders [see footnote 2]. Look at the word order and tell me if you would pick that combination if you were not trying to imply Y over X when you have X over Y. What would the real numbers say? Let's take a look.
There are about 120-ish million females in this country over the age of 18 [as calculated with an assumption of equal age distribution across genders from US Census Quickfacts]. About 7% of 18 and up females identify as vegetarian according to a recent Gallup poll [no definition specified]. That means about 8.5-ish million females in that age range are semi- to full-vegetarians. Another site estimates about 7 million women suffer from eating disorders. While there is no reason to assume this would be specifically 18-and-up, that comes to about (I'm going to assume 80% of women are old enough to be counted) 5.5% of women having an eating disorder.
To continue, let's go ahead and bring in numbers from the original article on study: "The Inter-Relationships between Vegetarianism and Eating Disorders among Females"3. According to the study, 6% of women with no eating disorder in their past are vegetarian. With that 6% of 120-ish million non-disorder-suffering women being vegetarian, we get 7.2 million in the country. By contrast, the article says that people with history of eating disorders are 23.7% likely to be an active vegetarian. I do not know if that 7 million above only included women who were actively suffering from an eating disorder or included those with a past, but let's go ahead and assume that the number is for "ever suffered". Since the total number of sufferers is around 7 million, that gives us 1.6-ish million women with past-or-present eating disorders that are active vegetarians.
Added up, it slightly exceeds our 8.5-ish million female vegetarians, above, but then I made a slight allowance to include younger females in the mix. This number then gives us about 18% of female vegetarians having either a past-or-present eating disorder, and roughly a third of those are either completely recovered or partially recovered. Claiming that dietician sorts should prod young women to find out why they are being vegetarian4 comes across as a slight-to-great slag against vegetarianism when the vast majority do not have eating issues (82% versus 18% really is a "great majority", note).
Other things to note:
- The article considered [presumably non-religious] meat-based restrictions in one catch-all category. In some cases, this would include those who merely abstained from red meat [the question as quoted in the article was: "Have you ever considered yourself a type of vegetarian (eg, not eating beef but eating other meat; not eating any meat at all)?"], hardly vegetarianism at all, even if that broad definition has been used "in the literature". Finding out that a percentage of women with self-image issues cut out red meat to lose weight seems a lot less spectacular than the article would claim.
- While all of the Ped came from a clinic, 3/4 of the control group came from the college doing the study, with some percentage being students doing the study in exchange for psychology lab credit. Presumably polling a health/nutrition class would have brought back more in-line results.
- Men are about roughly 4/7 as likely to be vegetarians as women but only roughly 1/7 as likely to have an eating disorder. There is strong potential that understanding this difference in ratio would help to actually identify the phenomenon being discussed.
I think it would be fascinating to redo the study, looking at strict vegetarianism versus self-image amongst both sexes, and how the two things correlate, and do it from the stance of "How many vegetarians developed that lifestyle, and maintain it, because of underlying eating disorders?," possibly with a bent towards linking it to extreme orthorexia nervosa [a shout out that will possibly earn me flack] as well as the standard eating disorder culprits since presumably a fear of "unhealthy" habits would be the real connected disorder here. For now, worried parents, since over 2/3s of those with an active-disorder are not actively vegetarian, you end up having to wonder what your daughter is doing with that steak, don't you? I mean, maybe she needs to be grilled [no pun intended] about her eating habits post-haste!
[There are enough assumptions and roundings in my math, and the research article had such a small sample, that feel free to discount my findings, but I'm going to guess [yes guess, not declare] them to be fairly accurate. If you have some better numbers, feel more than free to contact me and let me know.]
OTHER BLOTS THIS MONTH: August 2012