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Dropping Weight,
Not Performance
By
Gale Bernhardt
For Active.com
Q:
Hey Gale - I'd love to get your
take on something. I've been researching this next topic for my cycling
group: encouraging riders to determine whether or not they're eating
enough when training. (Who better to write this than Mr. Bonk himself?)
When I did
some analysis on my own caloric intake and taking into account the
variables of (1) Body weight, (2) Riding intensity, and (3) Duration, I
quickly realized I was consistently training at a caloric deficit. Ok,
so the simple answer could be: eat more, right?
Now here's
where it gets tricky. If you have a rider who wants to deliberately
subject themselves to burning more calories than they take in for the
sake of weight loss (and I must confess I have a few pounds I'd like to
shed), the $10,000 question is, at what point does your caloric deficit
begin to affect performance on the bike? I found the following statement
and I think it is pretty revealing:
"If you
ride at too hard of an intensity you'll be depleting the glycogen stores
within your muscles rather than training your body to burn off fat."
So, given the above statement,
how would a rider know when they've taken the advantage of
calorie-burning from exercise to the point of glycogen-depletion from
muscle tissue, which presumably would be the threshold at which a rider
would begin to experience fatigue and a negative affect on performance?
When I read the literature on
manageable and safe weight loss, there seems to be a consistent figure
of 1.5 to two pounds per week that is considered safe and reasonable for
weight loss. Heck, I've lost that amount on one ride from becoming both
dehydrated and malnourished! Yes, Mr. Bonk may not be a good example,
but in our cycling world there are many riders looking to find that
balance between maintaining fitness and reducing weight.
Can you help? Thanks - G.A.
A.
Mr. Bonk, you have several good questions. Let me try to hit each one:
•How many
calories per day can you cut without cutting performance?
I've never seen
any specific research on this, but my personal experience and experience
with other athletes yields an answer of 200 to 500 calories per day,
average.
I write "average"
because if you do a big ride on a weekend day, you might find yourself
at an 800 to 1,000 calorie deficit at the end of that day. If you keep
trying to maintain an 800 calorie per day deficit over the long haul,
performance will suffer. People that have no sport performance
expectations can run that low, but competitive athletes cannot.
The day of the big
ride, you might end up being low by 800 to 1,000 calories, but the next
couple of days will likely find you eating a little more. There is
nothing wrong with that, as long as you
keep the weekly deficit at an average
of 200 to 500 calories per day. Bigger people can
usually go to the higher end and smaller people on the lower end.
If you need
formulas to estimate caloric needs, see the column
Maintaining Your Lean Mean Racing Machine.
•"If you
ride at too hard of an intensity, you'll be depleting the glycogen
stores within your muscles rather than training your body to burn off
fat."
It's not exactly
black and white. A point of clarification is that we are producing
energy aerobically (primarily burning fat) and anaerobically (primarily
burning glycogen) all the time, in concert. Even as you sit relaxed in
your chair, reading this column, you are producing some energy
anaerobically.
The percentage of
energy coming from aerobic production changes as exercise intensity
increases. So, yes, as you ride faster you will increase the percentage
of energy that comes from glycogen and decrease the percentage that
comes from fat and oxygen.
Whether or not you
will actually deplete your glycogen stores within the muscles (i.e.
"bonk") depends on how well your muscles were stored with glycogen
before the ride, how fast you are riding and how well you are refueling
during the ride.
Also know that
higher-intensity exercise burns more calories per hour and does rev-up
your metabolic engine. Increasing your base metabolic rate is a good
thing.
Not bonking and
not over-consuming calories during a ride takes some experience and the
ability to increase or decrease calories on the fly, or by plan. This
means increasing or decreasing your ride fuel rate depending on the type
of ride you're doing, the condition of your fuel stores coming into the
ride and whether or not you are trying to lose weight.
You might fuel at
a rate of 200 calories per hour for an easy ride, but need more like 400
per hour for a very long day in the saddle or a ride with some intensity
blended into the mix.
•Safe and
reasonable weight loss at 1.5 to 2.0 pounds per week.
The range you
mention is safe, but know that two pounds per week means 2 x 3,600
calories per pound = 7,200 calories less per week than you are now
consuming to keep your current weight.
Averaging that out
per day means a deficit of around 1,000 calories per day. That deficit
is really tough to do in a normal training situation (not a training
camp or a bike tour) while keeping your performance from dipping.
When most people
begin a weight loss program, some of the battle is managing hunger (or
imagined hunger) and replacing old, bad habits with new ones. If you are
able to drop some weight and not decrease performance, let us know how
it goes, what you did and if you used any of these tips. |
