We are often asked, “Is it safe to mix
fruits and vegetables in my smoothie? What about ‘food combining’?”
The most relevant point in considering
whole food blending is that when using a high-speed blender, you are
"homogenizing" the foods, which makes it one drink (just like eating
a food that contains a spectrum of macronutrients: fat, protein, carbohydrate,
etc.), so your body digests as such, not as if the foods were separate
foods. Secondly, the blender pre-digests the food, breaking down the cell
walls so the body doesn't work as hard in the digestive phase of
metabolism.
Still, I was compelled to look further
into this food combining theory to find out just what the real deal was…
One very important clarification to start
with is that greens, including kale, spinach, romaine lettuce, etc., are NOT
the same as starchy vegetables, which are what most warnings against combining
fruits and vegetables are based on. They are plants, just as the green
tops of carrots are not the same as the carrots themselves. There are a
variety of categories of fruits and vegetables, including starchy, greens,
sweet fruits, sour fruits, and so on. Lumping them together is a common
mistake. Greens are perfectly fine to mix in smoothies. Actually, greens
are the only foods that help digest other foods through stimulating the release
of digestive enzymes.
Some proponents of food combining include
carrots (and beets) as starchy foods to avoid mixing, some say that carrots are
an exception. The biggest thing (because EVERYONE has different
reactions, and some people are just fine mixing anything and everything, while
others experience better feelings and results by adhering to different rules)
is how is YOUR body reacting? Are you gassy, bloated, and constipated? If
so, first thing to do is slow down and "chew" your smoothie, which
helps stimulate the release of the enzymes in your small intestines. If you
still experience digestive disturbances, then try reducing
ingredients.
Surprisingly, there is little direct
research on food combining ideas. Many of the rules say no dairy with
fruit, no carbs with meat, no vegetables with meat... do you divide these
foods? How many people do you know are doing that? And in direct contrast to
these rules, we know that consuming salad, for example, requires a fat such as
oil in order to really absorb the nutrients, such as carotenoids.
The only reasonable theory behind not
combining fruits and vegetables is that fiber and oxalates can bind to minerals
like calcium, magnesium and potassium and prevent their absorption, but that
does not require food combining as high-oxalate vegetables by themselves would do
that without eating anything else.
The original and main principle behind
food combining was/is based around the pH levels required for digestion and
it's effects on nutrient absorption and digestion time. The 4 common
rules cited are:
- "Always
eat fruit alone and at least 20 minutes before anything."
- "Eat
starches alone or with cooked non-starchy vegetables."
- "Eat
meat, dairy, fish, eggs and other high protein foods alone or with cooked
non-starchy vegetables"
- "Eat
nuts, seeds, dried fruit with raw vegetables."
A deeper look reveals that these rules
are not supported by any evidence and most are myths.
First we will address that carbohydrates
digest better in an alkaline environment. This is true as amylase enzymes only
occur in the mouth and then intestines. Here is the biochemistry: The
stomach is always acidic when eating any food as the stomach acids are released
every time you eat, no exceptions. When what you have eaten enters the
stomach, it is formed into a substance called chyme, which is then released
into the small intestine and acted upon all together. The pancreas then
releases it's own digestive enzymes along with bicarbonate to neutralize the
stomach acid and create alkaline environment for carbohydrate digestion.
However, this process is triggered proportionally to the level of the pH
(acidity) of the contents entering the small intestines. Eating protein
with carbs or fats, then, may actually increase digestive capacity and help
digestion, which is exactly the opposite of this theory.
Secondly, your body makes the enzymes
that release into the small intestines: lipase, amylase and trypsin, to work on
different components of the food: carbs, fat, protein. So based on the
very processes of the body, we can see it basically knows that it is going to
get a mix of nutrients.
We now know that when you eat, everything
passes through the digestive tract the same. The enzymes produced in the small
intestines are produced EVERY TIME...regardless of what you eat... and what is
needed at that time gets used. In fact, based on our modern understanding
of the biological processes, we find that digesting protein and carbs together
is the default setting of the body...which would be a no-no based on these
common food
combining rules.
Many foods contain multiple
macronutrients all in themselves, so obviously the body can handle processing
more than one at a time. Take the white potato (which we don't eat, by
the way, because it is SO starchy)...8 ounces of a baked white potato contains
4.76g of protein and 1% of your RDA of fat. Yet it is considered a
starchy carbohydrate.
The theories of food combining were
originally introduced at the end of the 19th century. While our
understanding biologically has grown, some myths still persist. Many of
the "problems" brought up in regard to food combining are
indigestion, weight gain and fatigue. It's not hard to see why many
people report improvements on these conditions when following these
guidelines. They are eating cleaner and less. Naturally, less food
is consumed at one time if you are just eating your vegetables alone, waiting,
eating the next food alone, and so on. When you are not overfilling, that
naturally improves digestion, reduces fatigue and enhances weight loss.
The biggest telltale sign is how things
react in your body. It would be like your neighbor saying they get really
bad gas when they eat garlic, so therefore garlic cannot be properly digested,
causes gas, and no one should eat it. We frequently hear and repeat
without much personal verification, and our instant access to perceived facts
on the internet and social media tend to propagate the information with little
understanding of actual journaled research to support the claims.
As always, do not rely on someone else to
care for your health. Educate and empower yourself, and take charge of
your own health!