Hi, I'm Dr. Tracey Marks, a psychiatrist,
and I make mental health education videos.
Today I'm talking about intermittent fasting
and how it has an antidepressant effect.
In my video on magnesium, I talk about how BDNF
is like fertilizer for the brain.
BDNF stands for brain-derived neurotropic factor
and it's low in people who are depressed.
BDNF stimulates growth of your nerve cells
in your hippocampus and other brain regions.
And new cell growth
is the mechanism behind brain plasticity.
You want your brain to be as plastic
or flexible as possible.
That is you want to be able to form new cell connections
that help you adapt to changes in your environment.
And BDNF makes that happen.
BDNF also increases serotonin
so when you're depressed you have lower levels of BDNF.
Antidepressant medications increase BDNF
and so does extended fasting.
Fasting increases ketones which trigger BDNF production.
Also, extended fasting increases ghrelin
which is the hunger hormone.
An increased ghrelin improves depression
through the chemical orexin.
That's a very simplified overview
of the biochemistry behind fasting
and improved mood in brain health.
I have references in the description
if you want to dive deeper into the chemistry.
There are many ways that you can intermittently fast.
Some people choose to fast for a whole day once a week
or they alternate days.
The more common way to do this
is to limit your eating window.
And what does that mean?
Let's say you have a nine to five job
and you wake up at 7:00 am.
You have breakfast around 7:30
and then you leave for work at eight.
You get home around six and have dinner around seven.
In this scenario, your eating window is 7:30 am to 7:30 pm
assuming it takes you 30 minutes to eat.
You have a 12 hour eating window
and a 12 hour fasting window.
If you sip a glass of wine on the couch
to wind down until 9:30,
you've extended your eating window to 14 hours
and your fasting window is 10 hours.
Now you may say wine is not food.
It's not solid food, but it's carbs
and to your body carbs is food no matter where it came from.
And this is probably the pattern of many people,
to have this long period where you're eating food.
An ideal fasting window to get this effect
of the increased BDNF
is about 16 to 18 hours for your window,
your fasting window.
A 16 hour window means eight hours of eating
and then six hours of eating for an 18 hour fasting window.
And these are ideal windows, but you need to build up to it.
So the first step is to look at your schedule
and figure out what your normal eating window is.
To go back to my nine to five example,
my eating window without the evening wine is 12 hours.
Step two is to establish your new window.
You want to add an hour or two to your fasting window
and then maybe increase it weekly.
You could even start slower by applying the new window
to just a few days a week.
So my step two is to increase my window to 14 hours.
Step three is to assign times to your new window.
I think the easiest way to do this
is to push back your breakfast.
Notice I didn't say skip breakfast.
You just want to push it back later.
If you push back your breakfast, you get to take advantage
of your sleeping window hours towards your fast.
And that's what we normally do.
To do this, you would start
with when you finish your last meal
and then count ahead 14 hours
or whatever your window, your fasting window is going to be.
You may prefer to keep your breakfast the same
and have your last dinner earlier.
The disadvantage of this
is that it may mean having dinner at work
and then you have a longer time
in the late afternoon and evening
that you're awake and not eating.
If you live with other people who aren't following the plan,
you have to watch them eat dinner while you fast.
In my nine to five work example,
to extend the fast to 14 hours and have dinner at seven,
I would not have any carbs after dinner
and then I would have breakfast at 9:30 am.
Since I would already be at work at that time,
I'll have to take my breakfast and eat it at work.
If that's inconvenient because I'm seeing patients at 9:30,
I can try and move up my dinner to 6:00 pm
and then eat while I'm driving, around 8:30.
This brings up the issue
of who this might not work well for.
This gets nitpicky and very detailed
and being on a strict schedule like this
with precise timing may not work very well
for a person with OCD or ADHD.
Also, the attention to detail that this requires
may stir up a person's eating disorder.
You want to be generous with drinking water
when you're fasting.
You can drink coffee or tea without sugar,
but make sure you also drink water
to offset the dehydrating effects of the coffee and tea.
What I described is not as drastic of a change
as 24 hour fasting.
Establishing these windows condenses the time that you eat
so you're not grazing on food for all of your waking hours.
You eat while you're expending energy,
then you stop, you sleep and you rest your mind and body
and then you break the fast and eat again.
It's important to realize that intermittent fasting
is not a diet.
It's a schedule adjustment.
When you eat, you still need to make healthy choices
about the foods that you eat during your window.
Some people will try and go all in
with a very short eating window
for which they think will get the maximum results
and when they get to their window,
they stuff down massive amounts of unhealthy food
because one, they're starving
and two, they feel like they've earned it.
If you do this, the inflammation
created by the unhealthy food
offsets any gains from the extended fasting.
Watch this video that I did talking about gut health
and then this one on magnesium for depression and anxiety.
Thanks for watching. See you next time.