Not long ago I found myself
in a situation you can probably identify with. My family and I were on a
weekend trip with another family and for breakfast I made myself a four-egg
omelette. I threw together a bowl of fruit as an extra and then sat down to eat
as our friends looked on in horror. One of them asked, politely, why I ate that
much. “Because I’m hungry,” I said between bites. If I didn’t eat this much
now, I explained, I’d be crazy hungry later.
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But what they really wanted
to know was how I could get away with eating that much. I was
the leanest adult in the room – and yet I ate more than the others.
Logically, people who are lean must eat less. Right? Otherwise they
wouldn’t be lean. What could be simpler?
That’s what Bernard Gutin
believed back in 2000, when he began his study of 800 teenagers. The goal was
to look at the relationship of diet and physical activity to risk factors for
cardiovascular disease. “We thought exercise and diet would play a role by
making kids less likely to get fat and less likely to develop risk factors for
these adult diseases,” he says. “We assumed the kids who ate the most would be
the fattest.” But they weren’t.
Instead, Gutin and his team
at the Medical College of Georgia found that the kids who ate the most were
typically the leanest. In some cases, the fattest kids actually ate less than
their lean counterparts. Naturally, the researchers assumed that physical
activity would explain the discrepancy. “We thought the leanest kids must be
exercising a lot more; so even though they were eating more, they were also
moving more,” Gutin says.
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according to a sports physio
But that wasn’t entirely
true either. Total physical activity – the amount of time the kids spent up and
moving – wasn’t a strong predictor of which kids would be leaner than others.
What mattered was how much
vigorous exercise they did – how much time they spent running, jumping, lifting
and playing sports.
This seemed improbable at
first. But even a few minutes a day of high-effort exercise was enough to
separate the leanest teenagers from the fattest. How could that be?
But before we talk about why
this matters, let’s start with an important qualifier: The leanest kids didn’t
necessarily weigh less than the fattest ones. But they did have better body
composition – that is, more muscle and bone, and less fat. And the only factor
that explains it is the amount of exercise that had them moving fast, elevating
their heart rate and forcing their muscles to work hard.
Now here’s why this article
is billed as a weight loss story, not a fitness piece: Sometime in the late
20th century, health experts decided that most people weigh more than they
should. An estimated 500 million adults worldwide are now considered obese.
They tell us we’re all overweight because we eat more than we should. The
obvious solution seemed to be: Eat less and then weigh less as a result.
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you lose weight
You’re considered overweight
if your body mass index, or BMI, is between 25 and 29.9. For a 1.78-metre guy,
the overweight range is 79 to 95kg. Anything more is classified as obese. If
you’re an athlete, a serious lifter or just a guy who’s active and not
obviously thin, you’re probably “overweight”. Chances are you’ve been told as
much by a well-meaning doctor.
And yet, according to a 2013
US Centres for Disease Control (CDC) review, people who are “overweight”
actually have a lower risk of mortality than people who fall in the normal BMI
range. The researchers were at a loss to explain why heavier people might live
longer. One possibility is that their higher percentage of lean mass helps make
them stronger. And there’s plenty of evidence that stronger people live longer
and have lower risks of cancer and heart disease. In fact, muscular strength is
connected with reduced risks of almost every health condition associated with
Most importantly, stronger
people tend to have less body fat generally and less belly fat specifically. In
other words, they’re leaner not because they weigh less but because they have
more muscle mass and once you have that muscle, you can use it to attack the
Another reason to focus on
exercise first when managing your weight has to do with two competing
systems in your brain. There’s the reflexive system – the “default responder,”
which we share with our evolutionary cousins, the great apes. It’s the “see a
doughnut, eat a doughnut” portion of the brain. When we
have unlimited access to high-kilojoule, low-nutrient food, this part of
our brain would put any of us into a diabetic coma if left unchecked.
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sabotaging your weight loss
That’s why we need to
strengthen its opposite, the reflective system. This one manages impulses,
keeps us focused on our goals and is unique to humans. Self-control is a lot
like your muscular system. You can make it stronger. But like your muscles, it
must be trained in a way that builds it up instead of breaking it down.
The best place to start is
with a solid exercise programme. “It’s not fitness to burn kilojoules,” says Dr
George L Blackburn, director of the Centre for the Study of Nutrition Medicine
at Beth Israel Deaconess Medical Centre in Boston. “Even sleep burns
kilojoules. It’s fitness to be fit.”
Dr Blackburn is one of the
authors of a recent study published in Obesity Reviews that
describes the many benefits of exercise beyond the modest effect it has on your
Improved insulin sensitivity
and other hormonal responses to food
An overall sense of
competence and accomplishment
Motivation to improve other
Those last two tie together
the psychological and physiological benefits of exercise, both of which are
crucial to anyone who’s struggling to stick with a workout programme. You won’t
reap any of the rewards we’re talking about if you can’t bring yourself to
train in the first place.
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That brings us back to
Gutin, who at age 79 has spent decades studying exercise. (He’s a professor
emeritus at both Columbia University and the Medical College of Georgia.) And
he still isn’t quite sure what to make of the results of his own research. But
he has a theory.
The human body is loaded
with stem cells; these can become different types of cells, depending on
what the body needs and what it tells them to become. In lab animals, the
combination of exercise plus food triggered stem cells in the bone marrow to
transform into lean tissue – muscle.
Overfed mice that were given
an exercise stimulus created more lean tissue. In other words, a higher number
of their stem cells turned into muscle and bone. But when the mice were
overfed and didn’t exercise, more of their stem cells turned into fat.
We can’t say this is exactly
what happens in humans, especially adults. (Even in rodents, the exercise
benefit isn’t realised if the animals are already obese.) But with kids,
something very much like this seems to take place. “Kids who do a lot of
vigorous physical activity develop less fat and more lean tissue,” Gutin says.
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In adults, we know that
satellite cells – stem cells found in muscle tissue – can become new muscle
cells at any age, given the right stimulus. And one good stimulus, Gutin says,
would be to work to momentary muscle failure when you lift. That way, without
having to guess, you know you’re generating a lot of force with your muscles.
This, in turn, stresses your connective tissues, which then strain your bones.
That should be enough to push some cells to become new lean tissue and perhaps
also prevent some cells from becoming fat.
Strength training isn’t the
only way to deploy muscle in the righteous war on fat. Your heart is also a
muscle and it may be the most potent weapon you have. Back in 1990, a team of
researchers overfed a group of healthy, normal-weight young men and limited
their physical activity during a 100-day period. The group’s weight gain
averaged around eight kilos – about two-thirds of it fat and a third muscle.
But there were huge disparities among the results.
In a recent study published
in the International Journal of Obesity, the researchers analysed
the same data and determined that prior to the overfeeding, those with the
highest VO2 max (a measure of aerobic power and fitness) gained the least total
weight and the least fat.
The best and fastest way to
improve your VO2 max is with short bursts of high-effort activity – such as
sprints, calisthenics and sled pushes. That’s exactly the strategy Gutin found
to be the key to lean, healthy bodies among the young people in his study.
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Before you set out to train
hard and fast, let’s circle back to my breakfast. As I explained to my friends,
I ate more than they did because I was hungrier. And I was hungrier
because of the way I train and because of the metabolic demands of being
relatively lean and fit.
But no amount of exercise
gives you a lifetime pass to eat whatever you want. It simply allows you to eat
what you need without worrying that an extra bite here or there will go
straight to your gut.
And if some of it does?
Well, you already have the tools you need to take it off. If you feed your
muscles, they’ll repay the favour by starving your fat.
This article was originally published on www.mh.co.za
Image credit: iStock