Intermittent Fasting
The Benefits of Intermittent Fasting
Intermittent fasting, or IFing, is a very popular
strategy for stimulating healing, increasing longevity, balancing hormones,
increasing energy and mental clarity and losing weight. If you’ve heard this term bantered around
paleo circles and have been wondering what it’s all about, then wonder no
longer!
How does
Intermittent Fasting work? Intermittent
fasting provides a variety of health benefits, predominantly due to stimulating
a process call autophagy. Autophagy is the process by which a starving
cell can reallocate nutrients from cell machinery that is not working optimally
to fuel more essential cell processes. The cell degrades its own components,
including damaged organelles, cell membranes and proteins, in a tightly
regulated process. Autophagy can destroy
viruses and bacteria within the cell that are resistant to other ways a cell
might destroy them. It can even help the
cell identify a viral infection that may have otherwise gone undetected. Autophagy
plays a crucial role in immunity and inflammation, balancing the beneficial and
detrimental effects of immunity and inflammation, and thereby may protect
against infectious, autoimmune and inflammatory diseases. It may
even prevent cells from becoming cancerous.
Autophagy plays a normal part in cell growth, development, and
homeostasis, helping to maintain a balance between the synthesis, degradation,
and subsequent recycling of cellular products. In fact, failure of autophagy is thought to be
one of the main reasons for the accumulation of cell damage and aging. Turning on autophagy is extremely beneficial
(whether it’s turned on by intermittent fasting, exercise, ketosis, or straight
calorie-restriction). The result is
healthier, more efficient cells, which means a healthier, more efficient
body.
What are the
benefits of Intermittent Fasting? The benefits
of intermittent fasting can be inferred from the effects of autophagy. However, more and more scientific studies are
being conducted to confirm the effects of Intermittent Fasting and also isolate
the optimal strategy for putting it into practice. Many of the benefits listed below have not
been directly tested in humans using Intermittent Fasting; however, there is
either strong evidence from animal studies or evidence from studies of
autophagy itself, combined with anecdotal evidence to support these
claims. The benefits of Intermittent
Fasting include:
- Increasing lifespan.
- Increasing insulin sensitivity, which has many health benefits in and of itself. Of interest, the resulting increase in insulin signaling in the brain is thought to be how fasting/calorie restriction works to increase lifespan.
- Lowering blood lipids, triglycerides and other markers of metabolic syndrome.
- Fighting/preventing cancer. There is also some evidence that fasting before chemotherapy treatments can help reduce the negative side effects.
- Increasing growth hormone secretion (which builds muscle and burns fat).
- Normalizing expression of the hunger hormone ghrelin, thereby reducing appetite.
- Promoting brain and peripheral nervous system health by increasing neuronal plasticity and promoting neurogenesis, which has a large variety of effects such as boosting mood, memory, and mental clarity.
- Increasing dopamine production, thereby boosting mood and increasing anticipation and response to rewards (meaning we get more enjoyment from less food).
- Increasing energy through regulating metabolic hormones.
Intermittent
Fasting is a little like hitting a reset button. It can help curb sugar cravings, restore energy,
and even promote deeper sleep.
How do you do
it? And how often? There are many options, but in general fasting for at
least 16 hours is required to receive any benefits. Fasting beyond 24 hours doesn’t extend those
benefits. So consider a fast anywhere
between 16 and 24 hours. This includes
sleep time, so a great way to intermittently fast is to simply skip breakfast.
Ideally, that also means skipping your morning coffee. Drinking water is okay. Expect to feel hungry when you fast. This is different than simply listening to
your body’s cues and waiting until you are hungry to eat (although many people
are opportunistic about when they fast and simply choose days when they aren’t
that hungry anyway). If you want to fast
for 24 hours, you can skip breakfast and lunch.
In terms of frequency, it is perfectly safe to fast 2 or 3 times per
week (in the absence of health conditions that might complicate matters). If you prefer a longer fast, then once or
twice per week is fine. Some people opt
to have an 8-hour feeding window every day (see Leangains). However, I would
argue that a daily fast is no longer intermittent. The body is able to adapt and predict the
fast and many of the benefits are dulled.
I also want to point out that you can benefit from fasting even if you
do it very infrequently. Perhaps you
only want to fast once per month, or once every few months. There is no clear evidence that fasting
frequently will dramatically improve your health. Try it, see how you feel, see how you feel
when you try it the next time, and then decide what is best for you.
What should
you break fast with? When you are
ready to eat, eat a balanced meal with lots of great protein and tons of
veggies. You probably won’t feel very
good if you eat too many carbs, so I urge caution with starchy vegetables and
fruit. And don’t overdo the quantity you
eat; try and aim for a normal meal (or only slightly larger than normal). I actually found in my own experimentation
that I wasn’t that hungry and would eat an unusually small meal to break fast
(I would then have more appetite for the meal after that).
Is fasting for
everyone? The answer to this is a resounding NO!
If you are not getting enough sleep or if your stress is not well
managed, you may experience exaggeratedly high cortisol production in response to fasting, which can be
detrimental. If you have a history of
metabolic derangement or adrenal fatigue, I urge caution for the same
cortisol-spiking reason. Women may be more likely than men to have an exaggerated cortisol spike in response to fasting (here's a great post reviewing women-specific responses to fasting). If you are not
currently eating a fairly low carbohydrate diet (say, less than 100g per day),
then fasting may have some side effects that mask the benefits (like headaches,
fatigue, and nausea, caused by high cortisol). If you have any
grains or dairy in your diet, you may experience a withdrawal-like effect
because you aren’t consuming the opiate-like substances found in those
foods. If fasting does not feel good, then don’t do it. If fasting feels good the first few times,
but then stops feeling good, then stop.
My own personal experience with intermittent fasting led me to realize
that I can only get away with doing a 16-hour fast 5 days a week, Any more frequently and the cortisol spike
stops weight loss, wrecks my sleep, and makes the whole experience completely
pointless.
Comments
Post a Comment