Aerobic vs Weight Training: Which is Better For Fat Loss (The Duke
Study – Was it Wrong?)
continue... (II part)
-Diet: The crucial (missing?) element
More than likely, one of the biggest reasons for less fat loss and
weight loss than you’d want or expect in 8 months is lack of tight control over
the subject’s diets.
A cursory skimming of the study suggests that they did have the subjects
report their food intake. However, a closer look at the full text shows it was
done with 3-day food records and 24-hour food recalls. It’s a well-proven fact
that self-reporting of food intake by research subjects is horribly unreliable.
A lack of weight loss can very often be chalked up to more calories being eaten
than were reported. No exercise program – weights or aerobics or both – works
well without proper nutrition.
Granted, studies with true control for food intake are difficult to
perform, especially for extended periods of time. But fortunately, we don’t
need more studies to understand what happened in this case.
We already know that the key to fat loss is the calorie deficit, not
aerobic training per se and not resistance training per se. It’s possible to
create a calorie deficit with ANY type of training program – cardio or weights.
However, is it possible to do aerobics and not have a deficit? Of course. Is it
possible to lift weights and not have a deficit? Of course! Is it possible
out-eat ANY training program? Of course.
The biggest question in my mind is why the researchers drew the
conclusions they did: Here’s what they said, word for word:
“If increasing strength and muscle mass is the goal, a program including
resistance training is required… (So far so good… we’re still
cool)…
“However, balancing time commitments against health benefits accrued, it
appears that aerobic training alone is the optimal mode of exercise for
reducing fat mass.” (Based on this data? Really? Okay, now we have a
difference in opinion).
I believe, and actually the absolute data seems to confirm it, that
resistance training plus aerobic training together trumps either type of
training by itself. The study authors themselves point out that each type of
training has its own set of benefits. But apparently, factoring in the
increased time commitment of doing both, they judged in favor of aerobics only
as the preferred option for decreasing fat mass.
That raises yet another question: Should losing weight or even just
losing fat be your only goal or your primary focus?
-Weight training: Key to the world’s fittest, leanest, healthiest and most attractive bodies?
I’m not sure what is the background of the authors of this study. Some
researchers have done mostly academic work, others have a practical background
in strength and conditioning. Here’s mine: I come from the trenches of a
personal training and competitive bodybuilding career, with a degree in
exercise science and I’ve held many personal trainer and strength coach
certifications. So, I’m definitely partial to weight lifting and
muscle-building as the best tool for transforming the body. However, I’m not
alone in my “bias”…
I’ve been surrounded by other professionals in the fitness trenches my
entire life and I don’t know a trainer worth his salt (one who actually
transforms other people’s bodies every day) who agrees that aerobic training
should be the sole focus of a fat loss program or even that fat loss should be
the sole focus of a health and fitness program.
Mind you, I’m not knocking aerobics – not at all. I’m a big fan of
including cardio as one part of the mix. That’s my whole point: It’s
practically common knowledge among experienced trainers that better body
composition is produced from combining weight training with cardio training.
There is a group of strength coaches and diet gurus today who insist
that weight training combined with very strict diet is sufficient to produce
fat loss. Surely that is true, but isn’t it also true that most people seem to
get better results when adding cardio on top of weight training? Aren’t there “endomorph”body types where weight training alone doesn’t seem to produce
the fat loss/ weight loss results wanted at the rate they are wanted? Didn’t
this study seem to bear that out? I can side with the researchers as far as
that goes: Weight training alone may not be optimal for fat loss for most
people. Put cardio into the mix.
I suppose a good question is how do we prioritize and allocate our time
to each activity? Following the same rationale as the researchers – balancing
time commitments with health benefits – shouldn’t weight training be higher in
the hierarchy than aerobics? Given the huge benefit list for weight training
(which includes better health), shouldn’t an ideal program start with weight
training plus nutrition as the core elements and then add cardio in to increase
fat loss and conditioning as needed? That’s how I see it.
For those with real time commitment issues, it’s comforting to know that
fat loss really can be achieved just by dialing in the diet (being meticulous
about caloric deficit), and that a calorie deficit can be achieved with any
choice of exercise. In a perfect world, I’d have you doing all three elements,
with that order of priority: Nutrition, weight training and cardio training and
adjust the prescription for the two types of training based on your goals and time
available.
-The muscle and metabolism argument: Was this point overlooked?
Although this study had limitations and subjects had less than stellar
results, it did have its strengths and it did raise some good questions. For
example, it has been widely believed for years, especially in the bodybuilding
world, that if increasing lean mass increases metabolism, then increasing your
lean mass will help you lose weight. It has sometimes even been implied or
stated directly that you can sit on the couch or sleep and (with your new
muscle), you’ll burn more calories and lose more fat from that alone.
The Duke researchers questioned this. They wrote:
“It may be time to seriously reconsider the conventional wisdom that
resistance training alone can induce changes in fat mass due to an increase in
metabolism.”
It’s well known that an increase in lean body mass leads to an increase
in basal metabolic rate. Therefore, for years, we have promoted the idea that
gaining lean mass helps with fat loss – and it does to some degree. However,
does it help so much that we can say increasing lean mass, by itself, is a
great fat loss strategy? If you only gain a few pounds of lean body mass, the
increase in metabolism is nothing to write home about. Without dietary control,
it’s no help at all.
It seems to me that the researchers could have made this their primary
conclusion. Instead, they said, “Aerobics is better than weight training for
fat loss.” That’s where I think they mixed up their message, because weight
training does help with fat loss in the short term, directly and significantly,
from increased calorie expenditure. Over the long term it helps too, but maybe
not as much as we thought purely from increased basal metabolism.
-Conclusions
Because the research is so inconclusive and opinions always vary due to
personal preferences and ideaologies, the weights versus cardio (and what kind
of each) debates are likely to continue. But if you consider the entire body of
research we have today on improving body composition, combined with the real
world experience of the top trainers and athletes who are in the trenches, you
can find it very easy to conclude that the optimal method of fat loss is a
combination of cardio training and resistance training.
Is more time required to do both resistance and aerobic training? Yes,
but with proper program design, time efficiency can be greatly increased. And
isn’t it worth doing both, so you can gain ALL the benefits: burning more
calories, increasing your strength, gaining lean muscle, decreasing your body
fat, improving your health and transforming your entire body shape?
Aerobics helps increase fat loss and you can lose body weight and body
fat with aerobics alone. But pumping iron should stay high on your fat loss
strategy list. Which of these two – cardio or weights – gets the most priority
and time from you may depend on your personal goals, but almost everyone can
agree that either way, controlling your diet is critical.
When you add in motivation and accountability, that increases compliance
to those first three elements, and you have as close to a “no fail” program as
you’ll ever have…Hey… doesn’t that sound a lot like Burn
the Fat, Feed the Muscle?
References:
Effects of aerobics and/or resistance training on body mass and fat mass in overweight or obese adults. LH Willis et al, Journal of Applied Physiology, 1831-1837, December 2012. Duke University Medical Center.
till
next time!
