There are tons of
different diet fads out there and you probably heard of a recent one,
known as Intermittent Fasting. Does fasting really help your
physique? Is it actually healthy to fast? Fasting has been around for
thousands of years. Actually, fasting is a type of practice in some
religions, such as Ramadan in Islam. A kind of fast that has the
followers not eating from dawn to sunset. This leaves the follower to
only eat for a couple hours a day. Why is it becoming popular now?
Martin Berkhan has been on the front lines of this new fad by raving
of its magical benefits to the followers who choose this method if
eating (www.leangains.com.)
Fasting has been said to drop fat while gaining muscle, increase
growth hormone production, help with insulin sensitivity, increase
energy, and decrease the hunger hormone. All these things sound
great, but are they actually true?
In one study, the
researchers found that resting energy expenditure raises during the
early fasting periods, (Zauner,
Schneeweiss, Kranz, Madl, Ratheiser, Kramer, Roth & Schneider,
2000). The results were
unbelievable and unexpected. Their has been previous studies done
that showed the opposite, which was a lower resting energy
expenditure during a fasting period. Apparently, an unfed individual
will actually increase his or her metabolism by simply not eating.
Zauner and his
colleagues found that not only is resting energy expenditure higher
during a fast, but the oxidation of fatty acid increases as well.
Fatty acid oxidation means fat is being mobilized and used as an
energy source. This is a great thing for people trying to change
their fat and gain more lean mass (Zauner,
Schneeweiss, Kranz, Madl, Ratheiser, Kramer, Roth & Schneider,
2000). However, the study was only
on healthy lean people to start with. The study doesn't apply to a
population who is overweight and seeking a healthy diet that will
support weight loss. The main take away from this study is that short
term fasting will increase metabolism due to higher levels of
norepinephrine. So, it seems that eating six meals a day could
actually hurt you.
The study by Zauner
was a little too specific to apply it to people, due to the lack of
varied subjects. Also, the study didn't seem to use exercise in
conjunction to the fasting. I found a study that had shorter periods
of fasts in conjunction with working out. This study compared 2
groups of lean males, one group fasted and trained in a fasted state,
and the other group had a carbohydrate rich breakfast 90 minutes
before training. The workouts were exactly the same with exactly the
same amount of rest time, sets, reps, and exercises. After the study
was completed, the scientists concluded that the fasted group had a
higher insulin uptake after ingesting the post-workout recovery shake
as opposed to the amount of insulin the fed group had. This is
important because insulin is a necessary hormone for muscle growth.
Therefore, the fasted group has a greater potential for growing
muscle in comparison to the fed group. The study also showed that the
fasted group had a much lower insulin level during exercise, which is
effective for burning fat. Fat is more easily mobilized when insulin
is not secreted (Deldicque,
De Bock, Maris, Ramaekers, Nielens, Francaux & Hespel, 2010).
These studies in
conjunction show that the dietary recommendations fed to us are
false. The government seems to believe small snacks and meals
throughout the day will help keep individuals healthy and in shape.
This study shows that not only is fasting more effective for weight
loss, but it is also more effective for gaining lean mass as well.
For a long time, people believed six meals a day would increase
metabolism, and then people debunked that as a myth. Then, people
believed that calorie is a calorie. But apparently, the same total
calories eaten in conjunction to fasting has a different effect then
believed to occur; the hormones make a difference in lean mass vs fat
mass (Deldicque,
De Bock, Maris, Ramaekers, Nielens, Francaux & Hespel, 2010).
Fat mass has been a
big problem in the World, because the amount of diseases that come
with the large accumulation of fat. These studies show a great start
to a new way of eating that can help our society get out of both
metabolic syndrome, and help insulin sensitivity (Zauner,
Schneeweiss, Kranz, Madl, Ratheiser, Kramer, Roth & Schneider,
2000). The amount of free form
fatty acid found in the blood samples of fasted individual is a
positive outcome as well. Instead of burning glucose, the
participants seem to use more stored fat as energy. Researchers have
been saying for a long time that it is impossible to burn fat and
build muscle at the same time, unless you are extremely overweight.
These studies give some insight that it may be possible, but its too
early to speculate and would be an interesting thing to research in
future studies.
In conclusion, the
studies that I chose to use were fairly straight forward with very
little limitations. The studies were conducted with full consent of
the subjects. The studies however had very little variation and
limits the ability to apply the studies to the general public. Future
studies on more age groups, mixed gender, and variable BMI's would be
helpful to see the application to the population. However, the
studies showed only positive results for lean healthy males, because
insulin is controlled in both studies by being lowered during fasted
periods, and increased exponentially in fed periods. This is helpful
for individuals trying to burn primarily fat during exercise while
taking advantage of the insulin response in post-exercise recovery.
Insulin is highly anabolic and can help increase the transportation
of nutrients into muscles. Also, metabolism seems to raise during
short term starvation. The researchers seem to not completely
understand the reason for the increase in metabolism. Zauner, et al.
Concluded that it was due the increase of norepinephrine
concentrations in the blood (Zauner,
Schneeweiss, Kranz, Madl, Ratheiser, Kramer, Roth & Schneider,
2000). Previous studies have shown
that large amounts of epinephrine will increase metabolism and is a
type of thermogenic. The norepinephrine nearly tripled on the fourth
day of fasting, which means, the body will continue to increase
metabolism the longer it is starved.
References:
Deldicque,
L., De Bock, K., Maris, M., Ramaekers, M., Nielens, H., Francaux, M.,
& Hespel, P. (2010). Increased p70s6k phosphorylation during
intake of a protein-carbohydrate drink following resistance exercise
in the fasted state. European
Journal of Applied Physiology, 108(4),
791-800. Retrieved from
http://link.springer.com/article/10.1007/s00421- 009-1289-x?no-access=true
Zauner,
C., Schneeweiss, B., Kranz, A., Madl, C., Ratheiser, K., Kramer, L.,
Roth, E., & Schneider, B. (2000). Resting energy expenditure in
short-term starvation is increased as a result of an increase in
serum norepinephrine. American
Society for Clinical Nutrition, 71(6),
1511-1515. Retrieved from
http://ajcn.nutrition.org/content/71/6/1511.long
