The Australian
January 18, 2014
Michael Mosley says a few short, intensive bursts of exercise each week can bring dramatic benefits.
A YEAR ago I wrote a book that changed my life. A middle-aged
medical journalist, I found myself the unlikely author of an
international bestseller, The Fast Diet, and the recipient of a lot of grateful emails.
based on a surprising and radical claim - that you can get fitter,
healthier and better toned with just a few minutes of intense exercise a
day, three days a week.
For those who missed it, the Fast Diet -
often known as "the 5:2" - is based on the idea of intermittent fasting,
also known as IF. Instead of aiming for slow, steady calorie
restriction - the approach recommended by sensible dietitians that most
people find impossible to stick to - with IF you slash your calories,
but for only a couple of days a week (hence the catchphrase the 5:2).
Although it may sound faddish, intermittent fasting is based on careful
scientific studies (mainly animal, but some human) that suggest it not
only leads to weight loss but has multiple other health benefits.
I was convinced enough by the science to make a documentary and then
to write a book. I remember, shortly after we delivered the manuscript a
year ago, pointing out to my co-author, Mimi Spencer, that there are
about 50,000 diet books available online and the odds of us making an
impact were, to say the least, slim. Mimi, who is an incurably
optimistic Tigger to my Eeyore, was convinced we would succeed because
our approach was offering not just a science-based diet but a modern
take on an old tradition. Fasting, after all, has a long history. "It
will be huge," she announced, as we sipped our calorie-free tea. She was
right. As well as numerous doctors, politicians and a Nobel
prizewinner, there have been endorsements from the likes of food writer
Hugh Fearnley-Whittingstall and actor Benedict Cumberbatch.
One of
the most striking things about the Fast Diet is how many men not only
embrace it but are happy to tell the world they are doing it. I think it
helps that "fasting" sounds challenging. It is also simple and
straightforward, which again seems to appeal to men. Mimi's father is
certainly a poster boy for this approach. Over the past few months he
has lost more than 16kg and has had to buy new trousers. This is
something I can identify with as I have lost 10kg, a few inches around
my middle and found that most of my clothes no longer fit. I hate
shopping but fortunately I have sons whose clothes I can now borrow (I
haven't told them). I'm also wearing suits from 20 years ago that I
never got around to throwing out.
Although I'm pleased with the
weight loss, for me intermittent fasting was never about getting
slimmer. Eighteen months ago I went to my GP with a suspicious mole and
she suggested I have my blood tested. The mole turned out to be benign
but the blood results were not. I had a fasting glucose of 7.3 mmol/l,
which made me diabetic, and a "bad" cholesterol (LDL) of 5.5 mmol/l (the
recommended level is less than 3). I shouldn't have been surprised
because my father, who struggled with his weight all his life, died of
complications from diabetes in his early 70s. I'd never felt the need to
diet because I had never seen myself as overweight. Yes, I weighed in
at 85kg, but when I looked in the mirror I saw someone slim, ageing
well, almost athletic. This wasn't simply a case of middle-aged
delusion; the surplus fat really was invisible. My fat wasn't sitting
under my skin, bulging out in unseemly places. It was visceral fat,
buried deep inside my body. I went for an MRI and saw not just the odd
dab but litres of the stuff inside my abdomen, coating and clogging my
internal organs. Visceral fat is particularly unhealthy because it is
metabolically active, increasing your risk of diabetes and heart
disease. It is surprisingly common, even in people of normal weight.
Rather
than start on a conventional diet, I decided to try intermittent
fasting. Unlike proper, hardcore fasting where you live for days or even
weeks on few if any calories, IF involves a few days a week when you
eat about a quarter of your normal calories. Being a television
presenter with a taste for self-experimentation, I naturally made a
documentary about my adventures. In the course of making Eat, Fast, Live Longer I
came across different ways you can do intermittent fasting. The
best-studied approach and the one that is likely to lead to the most
rapid weight loss is ADF, alternate day fasting. As the name implies,
you cut your calories every other day. I tried ADF but found it hard
going and settled instead on a 5:2 pattern, cutting my calories two days
a week. If you don't splurge on your non-fast days then this should
lead to a weight loss of almost half a kilogram a week.
Dr
Michelle Harvie and Professor Tony Howell of the Genesis Breast Cancer
Prevention Centre, who have done proper clinical studies comparing two
days a week of calorie restriction against a standard diet, found that
those on the two-day diet lost nearly twice as much fat (about 4kg) as
those on a standard diet, as well as seeing greater improvements in key
biochemical markers such as insulin sensitivity. Intermittent fasting
won't suit everyone, but it worked for me. Not only did I lose a lot of
fat (10cm off my waist, 5cm off my neck) but I also saw huge
improvements in my fasting glucose and cholesterol levels, both of which
are now in the healthy range.
Yet even when I was doing IF I knew
it was not enough. I realised that if I was going to maximise my
chances of living into a healthy old age then I needed to do more
exercise. The trouble is I hate running, jogging or going to the gym.
Instead, I've taken up a very different approach, pioneered by (among
others) Professor Jamie Timmons of Loughborough University. Jamie
introduced me to HIT, high intensity training. Like IF, HIT is a radical
solution to a modern problem, in this case how to get the most from a
workout in the least possible time. HIT also eschews the "moderation in
all things" approach. Instead of plodding away on a treadmill or cycling
at a steady, sensible pace, with HIT you do a few extremely short
bursts of exercise, intense enough to get your heart rate soaring,
interspersed with a couple of minutes of recovery. A few such bursts
(lasting anywhere between 20 seconds and one minute) done three times a
week can produce dramatic changes. Numerous trials have shown that HIT
not only makes people aerobically fitter in a remarkably short time but
also metabolically fitter. In particular, it improves the body's ability
to process the glucose surge you get after a meal. As someone with a
genetic propensity to develop diabetes, this is particularly important.
Early
versions of HIT were tough, best suited to those who were already
athletic. Modified versions have recently been tested on people who are
older, heavier and in less good health, such as those with heart
disease. Done properly it is safe, effective and surprisingly enjoyable.
It burns more fat than conventional exercise and, best of all, it's
over in less time than it takes to drive to the gym. A self-confessed
couch potato, I've been doing short versions of high-intensity training
for almost a year, with impressive results. During that time I teamed up
with journalist Peta Bee. Despite the fact that we have very different
attitudes to exercise (she loves it, I loathe it) and she started out
super-fit (I wasn't), we bonded over a mutual enthusiasm for HIT. We
hope HIT will be a hit.
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