"Auntie Em" Auntie wrote in message
...
How does genetics really figure in weight gain?

Genetics relates to weight in two ways :
- Losing or gaining weight is still a straight matter of calories in vs
calories out. But, how much you benefit from extra calories and how much you
lose from not enough calories seems to depend on genetics. Also, different
people will have different metabolism or will burn more or less calories for
the same amount of exercise. So, some active people will be stable on a 3000
calories diet, while others will gain weight on the same intake with the
same activity level. For instance, several experiences (Rose in 1961, Sobal
in 1989) have shown that there is no *direct* relationship between obesity
and caloric intake. The Sims' study has shown that when force-fed large
amount of food (around 10,000 calories/day), people gained weight in very
dissimilar fashion - some people in the study barely managed to gain 12
pounds in six months.
- It seems everyone has a genetical weight (or rather fat percentage)
set-point. This means your body is trying its best to keep a pretty stable
amount of fat (with seasonnal variations). That's great news if your
set-point happens to be within what is fashionable. That's good news if it's
within healthy BMI values. This means that eating according to your hunger
will let your body do the work for you. But sometimes, your set-point is at
overweight values. Usually, this is not unhealthy, especially in women where
the fat tends to go in healthy locations (bellow the belly).

It *seems* there are also inherited non-genetics factors. Some studies (IIRC
in Nothern Europe) have shown that people who had suffered from famine had a
tendency to have children with better adaptation to famine. This goes
against the Darwinian theory and seems to fit the Lamack theory. The idea is
that only part of our genetics is expressed. So, the hormones from the
mother can have an influence on the fetus, by strenghtening or reducing some
characteristics. It's possible that famine triggers a set of metabolical
changes in the mother's body, and that some of them are long term, and that
these changes triggers other changes in the fetus, as a way to be better
adapted to the envirronment. I would be curious to see what happens long
term to babies born from mothers under a ketogenic diet (starvation, diet,
local conditions...), especially when you can factor out the cultural issues
(like, babies adopted right after birth).

So, you can indeed have genetics factors. Up to fairly recently, your
familly members were survivors. In case of famine, they were the ones with
the best survival chances. As you point out, your grandmother was not
*unhealthy*. She was just fat - and strong. But this has turned out as a
disadvantage in recent years. However, genetics is only a factor. I don't
think it can explain real obesity (BMI30) by itself. In most cases, it is
merely a single factor among many others (cultural, psychological, non
genetics metabolical traits...). It's perfectly possible to become fat
without any genetics factor. It's also possible to lose weight despite a
genetic factor. It might just be a little harder than for other people.
It's also worth considering how *slim* you want to be. If your body wants
you to be on the overweight side, aiming for very slim is going to be a
permanent struggle against hunger. But aiming for the "healthy but with some
fat left" range and building some muscle (which you might have a genetic
advantage with, after all, your grand mother was not a wimp) might be a very
workable compromise.

As far as I can tell from my fathers description of their diets there
wasn't
much food and there sure wasn't much meat except for the odd rabbit now
and
then, a chicken or maybe a little potted pork. Meals consisted of a LOT
of
fresh vegetables in the summer and lot of canned vegetables in the winter.
Lots and lots of beans, eggs, and whatever was available.

Yet, this woman was very heavy. Solid as a rock, mind you, with stamina
that would put a mule to shame. But nevertheless FAT!

My dad has much the same build. He eats like the proverbial bird and yet
weighs a good 210 on his 5"9" frame. He has always been "big", as I
recall,
even when he had intensly physical jobs.

It's perfectly possible that he eats more than he thinks he does. The
people who knows you only in daytime probably think you eat like a bird too,
because they don't see you having dinner. It's also pretty reasonnable to
think that all that weight is not only fat. That's what we used to call
"strong men", both fat and muscular. That's a genetic body shape, and until
recently, it was the best one to be born with. Then, you have to decide what
you want to do with your genetics. I have the same kind of shape as a man,
and I know that aiming for fashion-model buttless slim would be
unreasonnable. But I can aim for a BMI around 24-25 and build enough muscles
to make it look good, since building muscles comes very easy to me, merely
walking does the job on my legs. Unfortunately, that's something men have an
easier time with, because bulky is still a somewhat fashionable option.