OH! Magazine - Australian Version December 2013 (Australian Version) | Page 15

www.getlean.com.au

DR JOANNA
MCMILLAN

THE CONS
common and our bodies no doubt adapted
to cope with this. The whole so-called
‘thrifty gene hypothesis’ is based on the
idea that those with efficient bodies, who
wasted little energy and conserved it well in
times of famine, are those who have
survived to pass on their genes. Today those
thrifty genes are contributing to our weight
problem in an environment of abundant
energy-dense food and little exercise.
So one way of looking at things is that
integrating regular fasting into our
routine
is
just
emanating
the
environment we evolved to survive in.
But can it help us to get lean?
The truth is we don’t really know yet.
What we certainly know from animal
studies is that kilojoule restriction leads
to longer lives and lower risk of many
chronic diseases including cancer. There
is pretty good evidence that this occurs in
humans too. It’s just more difficult to test
since getting people to survive on lower
kilojoule intakes is not easy. There is also
some evidence that fasting has benefits
from a health perspective. For example,
studies of people at the end of Ramadan
has shown improvements in markers of
heart disease risk, such as blood
cholesterol profiles and insulin sensitivity.
Whether this translates into long term
reductions in risk is not really known.
Neither do we know enough about what
differences there are between different
fasting regimes. And is there any harm
from fasting?
What will certainly not work is if you fast
on two days, but on the other days overeat
and more than make up for the spared
kilojoules. I am also concerned with the
idea of ‘eat whatever you like’ on the other
days. Nutrient intake matters and, at least
to me, is primary over any effect on weight.
We need micronutrients and phytochemicals
such as antioxidants for optimum health –
meaning, what we eat does matter; it’s not
just about the kilojoules.

I also have some concerns over the long
term effects on gene expression. What if,
by regularly fasting, we simply ramp up the
genes associated with preserving energy
and fuel when limited food is coming in,
then get really good at storing energy when
we do eat, ready to cope with the next fast?
If this were to happen you’d have to keep
up the fasting routine forever just to remain
a stable weight. But should you stop
fasting, then you risk gaining extra fat
ready for the next fast that never comes.
We need to wait for the research to catch
up with the popular diet books, to
understand more about these effects.
Watch this space – at least one group in
Adelaide have a study underway and I’m
sure many more will follow.
So where does that leave us? Well I’m
giving you my thoughts and then it’s up
to you to decide whether it’s something
you think you want to try.

THE PROS
• You learn to feel properly hungry
and be OK with that. Sounds
funny on first read, but so many
people tell me they are rarely
hungry, or they are scared of
being hungry. We can easily
cope with one day of little food.
• Many people say they feel full
of energy following a fast day
and almost euphoric. That may
be from a sense of pride at their
restraint, or there may be
physiological reasons such as
giving the gut a rest.
• Provided you don’t go crazy and
overeat on the other days, it can
be a means of lowering your
weekly kilojoule intake and
chipping away at your fat stores.
• Unlike most ‘diet’s, you only
have to practice strict restraint
on two out of seven days.

• We don’t know the effect on
gene expression – do you just get
better at coping with the fast?
• You may feel tired, cranky and
dizzy on the fast day, particularly if
you are prone to low blood glucose.
• Fasting interrupts normal routines
such as family dinner or an
invitation out with friends.
• You may find yourself overeating
on the day before or after the fast,
thereby replenishing the lost
kilojoules
and
potentially
overcompensating for the fast.
• I’m yet to be convinced it’s a
good long term strategy – I have
a feeling many people will
quickly tire of it and the appeal
of a delicious meal will be all too
much to restrain from.
So the bottom line is, for some people this
approach may well be valid, but for others
it may just lead to more disordered eating.
I a wait further research results with great
interest. If you do want to give it a shot,
my advice is to really focus on healthy,
balanced eating to boost your nutrient
intake on the five normal eating days.
Restrain from intense exercise on fast
days, and ensure you consume your low GI
carbs on the other days to top up glycogen
levels – these will easily be used up on the
fast day. And be sure to avoid overeating
on the days before and after your fast.

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