3. Physical activity (PA)
You’re a fitness professional, so you know
this, but we’ll recap anyway. Physical activity
is the calories you burn from purposeful
movement, such as walking, running,
working out at the gym, gardening and riding
a bike. Obviously, how much energy you
expend through physical activity will change
depending on how much you intentionally
move around.
4. Non-exercise activity thermogenesis
(NEAT)
Non-exercise activity thermogenesis (NEAT)
is the calories you burn through fidgeting,
staying upright, and all other physical
activities except purposeful exercise. This,
too, varies from person to person and day
to day.
Considering all of these factors, this part
of the equation should more accurately be:
Energy out = RMR + TEE + PA + NEAT
Each of these is highly variable. Which
means the ‘energy out’ side of the equation
may be just as hard to pin down as the
‘energy in’ side.
tries to keep your weight steady when you take
in less energy and start to lose weight:
• Thermic effect of eating goes down
because you’re eating less.
• Resting metabolic rate goes down
because you weigh less.
• Calories burned through physical activity
go down since you weigh less.
• Non-exercise activity thermogenesis
goes down as you eat less.
• Calories not absorbed goes down and
you absorb more of what you eat.
It’s important to note that if you have lots of
body fat to lose, many of these adaptations
don’t happen right away or are very modest
initially. As you become leaner, however, this
adaptive thermogenesis really ramps up.
Reducing calorie consumption can lead
to a much lower rate of weight loss than
might be expected, and can even lead to
weight re-gain
Calorie cutting counterproductive?
In addition to these tangible effects on the
equation, reducing actual calories eaten
Revising the equation...
So, while the Energy Balance Equation
sounds simple in principle, all these variables
make it hard to know or control exactly how
much energy you’re taking in, absorbing,
burning, and storing.
So, revisiting that ‘simple’ Energy
Balance Equation, we can see that, actually:
Changes in bodily tissues = [actual
calories eaten - calories not absorbed] -
[RMR + TEE + PA + NEAT]
Reducing calorie consumption can lead to a much
lower rate of weight loss than might be expected,
and can even lead to weight re-gain
also causes hunger signals to increase,
causing us to crave (and maybe eat) more.
The net effect leads to a much lower rate of
weight loss than might be expected – and
in some cases, could even lead to weight
re-gain.
Setting better expectations
The calorie-cutting effect is just one example
of the amazing and robust response to
trying to manipulate one variable. There are
similar responses when trying to manipulate
each of the other variables in the equation.
The point is, metabolism is much more
complicated, and interdependent, than most
people realise.
Therefore, trying ‘what used to work’ for
you, or relying on calorie counting, often
won’t get you the results you want. As
your energy balance evolves, so must your
strategies for losing fat or maintaining your
weight.
Understanding energy balance means
setting better expectations about body
change. Losing weight, and keeping it off,
is accompanied by adaptive metabolic,
neuroendocrine, autonomic, and other
changes.
It’s also important to remember that how
your metabolism reacts to changes in energy
balance will be unique to you. How much
you can lose or gain will depend on your age,
your genetic makeup, your biological sex, if
you’ve had relatively more or less body fat
and for how long, what medications you’re
taking, the makeup of your microbiome…
and probably a whole lot of factors we don’t
even know about yet.
Knock-on effects of variables
Even if all the variables in the final
equation above were static, the Energy
Balance Equation would be complicated
enough. But things get crazy when you
consider that altering any one of the
variables causes adjustments in other,
seemingly unrelated variables.
This is a good thing, of course. Our
human metabolisms evolved to keep us alive
and functioning when food was scarce. One
consequence is that when ‘energy in’ goes
down, ‘energy out’ goes down to match it,
because we burn fewer calories in response
to eating less.
Likewise, when ‘energy in’ goes up, ‘energy
out’ tends to go up too, because we burn more
calories in response to eating more.
This isn’t the case for everybody, and
it doesn’t work ‘perfectly’, but generally,
that’s how it goes and how our bodies avoid
unwanted weight loss and starvation. It’s how
humans have survived for two million years.
The body fights to maintain homeostasis.
To illustrate this point, here’s how your body
Brian St. Pierre, MS, RD, CSCS
Brian is a US-based registered dietitian (RN), certified sports nutritionist (CISSN) and certified strength
and conditioning specialist (CSCS). He spent three years as the Head Sports Nutritionist and as a Strength
and Conditioning Coach at Cressey Sports Performance and is a nutrition coach with Precision Nutrition.
precisionnutrition.com
12 – 14 APRIL 2019 / ICC, SYDNEY
THE FITNESS INDUSTRY’S BIGGEST WEEKEND
IS BACK AND NETWORK MEMBERS SAVE!
Brian’s coming to Oz to share his insights at FILEX. Join him for:
•
•
•
•
•
Fat Loss: The Strategies That Really Work
Human Metabolism & The Calorie Conundrum
Calories, Macros, Portions – How To Best Track Intake
Fundamental Principles of Performance Nutrition
Meal Plans That Don’t Suck
Go to FILEX.com.au to check out the full program, featuring sessions on
everything from PT and Business, to Group Fitness and Nutrition.
Network Members get the best available prices: simply register for the
Member Rate using your Network Membership number.
NETWORK AUTUMN 2019 | 21