Optimizing Water Intake to Lose Weight
Two cups of cold water on an empty stomach a few times a day for weight loss. Boosting your metabolic rate through drinking water. Subscribe to …
"Optimizing Water Intake
to Lose Weight"
Drink two cups of water and you get
a surge of the adrenal hormone
noradrenaline in your bloodstream,
as if you just smoked a few cigarettes
or downed a few cups of coffee,
which boosts your metabolic rate
up to 30% within an hour, which,
when put to the test in randomized
controlled trials, appeared to accelerate
weight loss by 44%, certainly
making it the safest, simplest,
and cheapest way to
boost your metabolism.
Now, if you're on a beta blocker
drug, this entire strategy may fail.
Beta blockers are typically
prescribed for heart conditions
or high blood pressure
and tend to end
with the letters "lol," such as
atenolol, nadolol, or propranolol,
sold as Tenormin, Corgard,
or Inderal, respectively.
So, for example, if you give people
the beta blocker drug metoprolol,
sold as Lopressor, before they
chug their two cups of water,
the metabolic boost is effectively
prevented. This makes sense
since the "beta" that's being blocked
in beta blockers are the beta receptors
triggered by noradrenaline. Otherwise,
though, the water should work.
But what's the best kind of dose,
type, temperature, and timing?
Just a single cup may be sufficient
to rev up the noradrenaline nerves,
but additional benefit is
seen at two or more cups.
Caution: One should never drink more
than three cups in an hour, though,
since that starts to exceed the amount
of fluid your kidneys can handle.
If you have heart or kidney failure, your
physician may not want you drinking
extra water at all, but even with healthy
kidneys, any more than three cups
of water an hour can start to critically
dilute the electrolytes in your brain
with potentially critical consequences.
In How Not to Diet, I talk about the first
patient I ever killed in the hospital
as an intern. It was a guy who
drunk himself to death with water.
He suffered from a neurological condition
that causes pathological thirst.
I knew enough to order his liquids to
be restricted and have his sink shut off,
but didn't think to turn off his toilet.
Anyways, does it have to
be plain, straight water?
It shouldn't seem
to matter, right?
Water is water, whether flavored
or sweetened in some diet drink.
But it does matter. When trying to
prevent fainting before blood donation,
something like juice doesn't
work as well as plain water.
When trying to keep people from getting
dizzy when they stand up, water works,
but the same amount of water with
salt added doesn't. What's going on?
We used to think the trigger
was stomach distension.
When we eat, our body shifts blood
flow to our digestive tract, in part
by releasing noradrenaline to
pull in blood from our limbs.
This has been called
the gastrovascular reflex.
So drinking water was thought
to be just a zero-calorie way
of stretching our stomach. But
instead, drink two cups of saline—
basically salt water—and
the metabolic boost vanishes.
So stomach expansion
can't explain the water effect.
We now realize our body
appears to detect osmolarity,
the concentration of
stuff within a liquid.
Covertly slip liquids of different
concentrations into people's stomachs
with a feeding tube and you can
demonstrate this by monitoring
sweat production, which is kind of
a proxy for noradrenaline release.
This may be a spinal reflex, as
it's preserved in quadriplegics,
or picked up by the liver, as we see
less noradrenaline release in liver
transplant patients who've
had their liver nerves severed.
Whichever the pathway,
our body can tell.
Thought we only had five senses?
The current count is upwards of 33.
So maybe the Bruce Willis movie should
have been called The 34th Sense?
In my Daily Dozen recommendation, I
rank certain teas as among the healthiest
beverages. After all, they have all the
water of water with an antioxidant bonus.
But from a weight loss perspective,
plain water may have an edge.
That may explain the studies showing
overweight and obese individuals
randomized to replace diet
beverages with water
lost significantly more weight.
This was chalked up to getting rid
of all those artificial sweeteners,
but maybe instead the diet drinks were
too concentrated to offer the same
water-induced metabolic boost. Diet
soda, like tea, has about 10 times
the concentration of dissolved
substances compared to tap water.
So, plain water on an empty
stomach may be the best.
Does the temperature
of the water matter?
In a journal published by the American
Society of Mechanical Engineers,
an engineering professor proposed
that the secret of a raw food diet
for weight loss was the temperature
at which the food was served.
To bring two cups of even just room
temperature water up to body temperature,
he calculated, the body would have
to dip into its fat stores and use
up 6,000 calories. Look,
just do the math, right?
He says a calorie is defined as
the amount of energy required
to raise one gram of water
one degree Celsius.
So since two cups of water is about
500 grams, and the difference
between room temp and body temp
is about a dozen degrees Celsius.
500 x 12 = 6,000-plus calories
needed. Anyone see the mistake?
In nutrition, a calorie is actually a
kiloCalorie, a thousand times bigger
than the same word used
in the rest of the sciences.
Confusing, right? Still, I'm shocked
the paper was even published.
So, drinking two cups of
room temperature water
actually only takes 6 calories
to warm up, not 6,000.
Now, if you were a hummingbird
drinking four times your body weight
in chilly nectar, you could burn up to 2%
of your energy reserves warming it up,
but it doesn't make as much
of a difference for us.
What about really cold water, though?
A letter called "The Ice Diet"
was published in the
Annals of Internal Medicine
estimated that eating about a quart of
ice—like a really, really big snow cone
with no syrup—could rob our
body of more than 150 calories,
the same amount of energy as the
calorie expenditure in running one mile.
It's not like you directly burn
fat to warm up the water, though.
What your body does is just corral more
of the waste heat you normally give off
by constricting blood flow to your skin.
How does it do that? Noradrenaline!
If you compare drinking body temperature
water, to room temperature water,
to cold water, there's only a significant
constriction in blood flow to the skin
after the room temp and cold water.
And neither the warm or tepid water
could boost metabolic rate as much
as cold, fridge temperature, water.
So your body does after all end up
at least indirectly burning off more
calories when you drink your water
cold. So, two cups of cold water
on an empty stomach a few times
a day. Does it matter when? Yes.
Watch my Evidence-Based Weight
Loss lecture to see how you can add
the benefit of negative-
by drinking that water
right before your meals.