"The Downside of Green Smoothies"
If you split women into two groups
and tell them to eat as much soup as they want,
but half are given big spoons and told to eat fast,
and the other group is given small spoons and told to eat slow,
the slow group ended up feeling more satiated despite eating less food.
The thought is that prolonged meal duration can allow more time
for our own body’s I’ve-had-enough signals to develop
before too many calories have been consumed.
After all, we evolved for millions of years before cooking,
when undomesticated fruits and vegetables
were much tougher and fibrous.
Our body is built to expect us to take our time to eat.
There weren’t any blenders on the African savannah, either.
In smoothie form, you can drink fruits and vegetables
at about 2 cups a minute, 10 times what it might take
to eat them in solid form.
Liquid calories can be consumed so quickly
they can undermine our body’s capacity to regulate
food intake at healthy levels.
It’s not the liquid texture per se,
but the high rate of consumption at which liquids
are normally consumed and so blend all the smoothies you want,
but better to sip them slow, over a half hour or so
rather than gulping them down.
Even slowly sipped, though, an all fruit smoothie
may not be as filling as whole fruit,
so the more greens you can add to your smoothie, the better,
and you can add ground flax seeds.
The thicker the smoothie, the less hungry you may be
1, 2, even 4 hours later,
and flax seeds make for thick milkshakey-type smoothies.
One tablespoon of flaxseeds was found to significantly
suppress appetite and calorie intake.
Less hunger, more satiety, more filling, less prospective food intake,
meaning you give someone a meal 2 hours after the tablespoon of flax
and they eat significantly less.
all the while dropping our cholesterol.
This is just one week after about a tablespoon a day.
The fat naturally found in flaxseeds
can also help maximize the absorption
of fat-soluble phytonutrients.
There’s a threshold for optimal absorption that can be reached
with just like 3 walnuts worth of fat,
so if you’re trying to reduce added fats,
a green smoothie with some nuts, seeds, or avocado
can enable us to take full advantage
of the healthiest foods on the planet-
dark green leafy vegetables.
Smoothies also allow us to eat parts of fruits and vegetables
we might not otherwise.
If instead of lemon juice here in Mayo’s basic green smoothie recipe,
you used a little wedge of lemon, instead,
you might get some seeds and peel,
which in vitro at least appear to suppress
both breast cancer and colon cancer cell growth.
Clinical studies on smoothies show what you’d expect to see
from eating great foods like greens and berries—
enhanced athletic performance and recovery,
boosting the antioxidant power of your bloodstream,
potentially improving arterial function
in the short-term, and the long-term.
Kiwifruit smoothies protecting against DNA damage
and strawberry smoothies against inflammation.
Of course so would, presumably, just eating greens, kiwis, and berries intact.
There has been concern expressed that drinking green smoothies
would bypass the nitrate-producing bacteria in the mouth,
but our body’s way too smart for that
and pumps nitrate back into our salivary glands,
so even if you deposited greens directly in your stomach
with a tube you’d still produce the nitric oxide
so important for artery health.
Concerns have been raised at the oxalic acid
in vegetables might increase kidney stone risk,
but as I’ve explained in the past
if anything, the opposite might be the case.
So, are there any downsides of smoothie consumption?
Whether lemon juice or wedge, smoothies can be sour,
and any time you’re eating or drinking something sour,
you have to be careful about eroding the enamel on your teeth.
If you soak teeth in a smoothie for an hour,
significant enamel is eroded away,
but who soaks their teeth in a smoothie for an hour?
But what if instead of studying the effects of smoothies in situ,
meaning in position, as opposed to in vitro,
meaning in glass.
If you make people wear slabs of enamel in their mouths
while they drink a smoothie to replicate a typical tooth exposure,
they do find almost as much erosion as drinking diet coke,
so it’s recommended that smoothies be consumed through a straw,
similar to the advice given for other acidic beverages
like soda or hibiscus tea.
Compared to control, drinking juice through a straw
has less of an acidic effect than swishing it around in your mouth,
so avoid swishing smoothies around in your mouth,
and you want to wait at least an hour before brushing
so as not to brush your enamel in a softened state,
but rinsing your mouth out with water
after drinking smoothies is a good idea
as it can help rinse away some of the acids to protect your teeth.
And one final caveat for smoothies,
when I advocate green smoothies to boost fruit and vegetable consumption
I’m talking about whole food smoothies,
not made from juice, or added sugars, or...human organs.
Some women choose to consume their afterbirth.
Though described as “replenishing and delicious,”
the problem with eating your placenta
is that one of the functions of the placenta
is to filter out toxins,
and so may be contaminated with heavy metals,
as well as pose a food poisoning risk
if consumed raw like in a smoothie.
Green smoothies are great, but I’d be cautious
about drinking certain types of red smoothies.