"Science" is supposed to be a product of the scientific method, and
this method is not particularly complicated in these kinds of
situations. In essence, any possible causative agent is controlled for
in an experiment, or series of experiments, in order to determine what
is responsible for the phenomenon in question. Today, it is common to
hear people who claim to be "nutritional experts" of one sort or
another to make statements as bold as "trans fat is very unhealthy."
Presumably, the believe that such a statement is scientific; thus, it
is appropriate to ask whether the scientific method was used to arrive
at these kinds of assertions. In this instance, it is at first
necessary to know exactly what the substance called "trans fat" is,
down to the molecular level, which is possible with current technology.
If this is not known, no experiment is can be conducted, and any claim
about "trans fat" is not within the realm of science.

Trans fatty acids are defined and known precisely, and occur naturally
in a number of foods that are very popular in many nations, but in
small amounts. Most "experts" seem to think that the hydrogenation
process is somehow to blame for the "ill health" they believe "trans
fat" causes. This makes experimentation simple; studies can be done on
lab animals commonly used in nutritional experiments of this sort. One
group would be fed a partially hydrogenated fat source (such as corn
oil) at levels considered significant while another group would be fed
a fully hydrogenated oil (such as coconut oil) and a third group would
be fed the oils without hydrogenation. The animals would be allowed to
live out their lives, and any outstanding effects would be noted, along
with the average mortality rates.

However, some on this newsgroup have argued that a fully hydrogenated
fat source can no longer be called a "trans fat." This is because there
are no trans fatty acids present, though the same hydrogenation process
was used. I agree that a distinction should be made, but this is not
what most "experts" are saying - their claim is that hydrogenation is
to blame for the supposed ill effects, and therefore a fully
hydrogenated oil should be at least as "bad" as the partially
hydrogenated oil. This is basic logic and no more needs to be said. The
results of the experiment proposed above should provide good evidence
in this context.

Now let us suppose that the fully hydrogenated oil generates no ill
effects and that the animals live at least as long as is considered
"normal." What, then, is to blame for the supposed ill effects of the
oil that is partially hydrogenated? Some "experts" (such as Mary Enig)
have claimed that the trans fatty acid molecules are "kinked" and cause
some sort of problem having to do with "cell membranes," but this is
speculation. Some make claims based upon various "markers," and not by
observing effects over the course of the lifetime of the animal, along
with recording mortality rates, and so this fails to meet the
requirements of the scientific method. Most of these kinds of
"researchers" simply assume that something that raises cholesterol
slightly, for example, is terribly dangerous, even though the "founding
father" of this notion, Ancel Keys, pointed out that the 200-220 total
cholesterol range was associated with the lowest mortality, and that it
is now known that only oxidized cholesterol is a problem, as AHA
spokesman Dr. Richard Stein pointed out about a year ago. In fact,
today, on sciencedaily.com, there was the following:

It is much more likely that the hydrogenation process destroys the
natural antioxidant protection that exists in the oil, and so is to
blame for the supposed ill effects, if indeed there are any, when
compared to the usual kinds of oils used to make partially hydrogenated
oil products. Therefore, it would make sense to add one more group of
animals to the experiment proposed above - this group would receive its
fat source as an corn oil (or safflower, sunflower, vegetable, etc. -
one typically used for making partially hydrogenated oils), only
instead of feeding it to the animals right from the bottle, it would be
spread thin and exposed to oxygen and sunlight for several days before
it was fed to the animal. In this way, it would not be hydrogenated,
and few trans fatty acids would be created, if any. However, the
antioxidants naturally occurring in the oil would be largely depleted,
and so the researcher would be controlling for the lipid peroxidation
factor in a direct way.

After the experiment was conducted, the results would likely "speak for
themselves." For example, if the fully hydrogenated coconut oil
appeared to be by far the healthiest fat source, then the only
reasonable interpretation would be that lipid peroxidation was the
causative agent.
The ambiguity over the phrase "trans fat" would no longer be
problematic. Instead, what is happening is disturbing; food companies
are creating new concoctions, ones that use fully hydrogenated fat,
which they can claim contains no "trans fatty acids," along with a
cheap and highly unsaturated oil, such as corn, sunflower, vegetable,
safflower, or soybean. If the real problem is not with what is being
called "trans fat," but instead with lipid peroxidation, then these new
fats will cause the same amount of ill health as equivalent "trans fat"
sources. Ironically, the "experts" who claim that the hydrogenation
process is to blame do not tell people to avoid these new concoctions,
which contain large amounts of a totally hydrogenated oil source,
though most if not all of them must be aware of it.

Lastly, I'll point out that one person who posts here as "MattLB"
claims that overall mortality is not especially important. However, if
a particular diet produces a great deal of ill health, the people or
animals consuming it will die at younger ages, so as is often the case
with this individual, his notion is unclear. I do agree that if a diet
is tasteless, unsatisfying, or causes intestinal upset, many people
will not follow it for very long. The diet I recommend, however, would
not fit this description. Moreover, after several years on this diet, I
have seen my "chronic" medical conditions, some of which I've had for
more than a decade, vanish (a tendonosis problem required more
protein). However, this "MattLB" person did not explain exactly what
criteria he/she would use to determine which diet was best, and until
he/she does so, there is no way to respond in a way that is consistent
with the scientific method. This person also claimed that the diet I
suggest is "abnormal," which demonstrates his subjectivity here.
Science is concerned with the results of controlled experiments, not
with what one person decides to classify as "abnormal." In fact, I do
not recommend eating any food that could not have been consumed a
couple of hundred years ago, and so this makes his/her claim
particularly absurd and difficult to comprehend.