Fat, Not Glucose, Is the Preferred Fuel for Your Body
by Joseph Mercola: The
Microscopic Zoo Within Us
While we may
consider ourselves to be at the pinnacle of human development, our
modern food manufacturing processes have utterly failed at improving
health and increasing longevity.
Paleolithic period, many thousands of years ago, our ancestors
ate primarily vegetables, fruit, nuts, roots and meat and
a wide variety of it. This diet was high in fats and protein, and
low in grain- and sugar-derived carbohydrates.
person's diet today, on the other hand, is the complete opposite,
and the average person's health is a testament of what happens when
you adhere to a faulty diet. Humans today suffer more chronic and
debilitating diseases than ever before.
And there can
be little doubt that our food choices play a major role in this
development. Quite simply, you were not designed to eat large amounts
of refined sugar, high
fructose corn syrup, cereal, bread, potatoes and pasteurized
As Mark Sisson
states in the featured article1:
want to live a better life and eat the best foods nature provided
for health and fitness, then it's time to ditch the old paradigms
and climb on to the primal approach to eating better."
Really Your Body's Preferred Fuel?
that glucose is the preferred fuel for your body is a pervasive
one. Everyone from diabetics to top athletes are advised to make
sure they eat "enough" carbs to keep their systems from crashing.
This is unfortunate, as this misguided advice is at the very heart
of many of our current health failures.
As Mark so
succinctly spells out in his article, FAT is actually the preferred
fuel of human metabolism, and this can be traced back to our evolutionary
speaking, carbohydrate intake has always been quite low. Likewise,
the diseases we now know are associated with insulin resistance
which is primarily caused by excess consumption of refined
carbs have been quite rare.
is both clear and overwhelming: Carbohydrate intake is the primary
factor that determines your body's fat ratio, and processed grains
and sugars (particularly fructose) are the primary culprits behind
our skyrocketing obesity and diabetes rates.
logically that if you can limit carb intake to a range of which
is absolutely necessary (and even up to 50 grams a day over) and
make the difference up with tasty fats and protein,
you can literally reprogram your genes back to the evolutionary-based
factory setting you had at birth – the setting that offered you
the opportunity to start life as a truly efficient fat-burning organism
and to continue to do so for the rest of your life as long as you
send the right signals to your genes," Mark writes.
Why the Low-Carb/High-Fat
Diet Works for Weight Loss
a carb-based diet to a fat- and protein-based diet will help rebalance
your body's chemistry, and a natural side effect of this is weight
loss, and/or improved weight management once you're at an ideal
weight. One explanation for this is that you don't really get fat
from eating too much and exercising too little. Nor do you get fat
from eating fat. One researcher that has clearly established this
is Dr. Richard Johnson, whose latest book, The Fat Switch,
dispels many of the most pervasive myths relating to diet and obesity.
discovered the method that animals use to gain fat prior to times
of food scarcity, which turned out to be a powerful adaptive benefit.
His research showed that fructose activates a key enzyme, fructokinase,
which in turn activates another enzyme that causes cells to
accumulate fat. When this enzyme is blocked, fat cannot be
stored in the cell. Interestingly, this is the exact same "switch"
animals use to fatten up in the fall and to burn fat during the
winter. Fructose is the dietary ingredient that turns on
this "switch," causing cells to accumulate fat, both in animals
and in humans.
overeating and excess weight could be viewed as a symptom of an
improper diet. It's not necessarily the result of eating too many
calories, per se, but rather getting your calories from the wrong
sources. In simple terms, when you consume too many sugars and carbs,
you set off a cascade of chemical reactions in your body that makes
you hungry and craving for sweets:
- First, fructose
is metabolized differently from glucose, with the majority being
turned directly into fat because fructose stimulates
a powerful "fat switch."
- This rapidly
leads to weight gain and abdominal obesity ("beer belly"), decreased
HDL, increased LDL, elevated triglycerides, elevated blood sugar,
and high blood pressure i.e., classic metabolic syndrome.
carbohydrates, especially fructose, are also the primary source
of a substance called glycerol-3-phosphate (g-3-p), which causes
fat to become fixed in fat tissue
- At the same
time, high carb intake raises your insulin levels, which prevents
fat from being released
further tricks your body into gaining weight by turning off your
body's appetite-control system. Fructose does not suppress ghrelin
(the "hunger hormone") and doesn't stimulate leptin (the "satiety
hormone"), which together result in feeling hungry all the
time, even though you've eaten. As a result, you overeat and develop
insulin resistance, which is not only an underlying factor of
type 2 diabetes, heart disease, and a long list of other chronic
equation is simple: fructose and dietary carbohydrates (grains,
which break down into sugar) lead to excess body fat, obesity and
related health issues. Furthermore, no amount of exercise can compensate
for this damage because if you eat excessive fructose
and grains the primary ingredients NOT found in our ancestral
diet it will activate programming to cause your body to become,
and remain, fat.
How Much Glucose
or Carbs Do You Really Need?
about whether or not you really need glucose, and if so, how much,
is by no means settled. Earlier this year, I ran a series of articles
featuring the back-and-forth discussion between two well-researched
experts on this topic, Dr.
Jaminet and Dr.
is a proponent of so-called "safe starches," and is of the conviction
that depleting your glycogen store can stress other systems to provide
the glucose your body requires to perform. Dr. Rosedale, on the
other hand, points out that because glucose consumption will undoubtedly
spike blood glucose levels and increase insulin and leptin, promoting
resistance, glucose consumption is always associated with
some incremental degree of damage and/or increased risk
of mortality. His diet is subsequently extremely carb-restrictive.
diet similar to Drs. Jaminet and Rosedale's is the
GAPS diet, created by Dr. Natasha Campbell-McBride, which is
specifically designed to help "heal and seal" your gut. As such,
it primarily consists of easily digestible, lightly cooked foods
that are high in protein, fats, and fermented foods, and low in
fiber and carbs.
also adds valuable insight to this discussion2:
one time, the total amount of glucose dissolved in the bloodstream
of a healthy non-diabetic is equivalent to only a teaspoon (maybe
5 grams). Much more than that is toxic; much less than that and
you pass out. That's not much range for a so-called 'preferred'
fuel, is it?
studies have shown that under normal low MET conditions (at rest
or low-to mid- levels of activity such as walking and easy work)
the body only needs about 5 grams of glucose an hour. And that's
for people who aren't yet fat-adapted or keto-adapted. The brain
is the major consumer of glucose, needing maybe 120 grams a day
in people who aren't yet on a low carb eating program.
eating reduces the brain's glucose requirements considerably, and
those who are very low carb (VLC) and keto-adapted may only require
about 30 grams of glucose per day to fuel the brain... Twenty of
those grams can come from glycerol (a byproduct of fat metabolism)
and the balance from gluconeogenesis in the liver (which can actually
make up to a whopping 150 grams a day if you haven't metabolically
damaged it with NAFLD through fructose overdosing).
line, unless you are a physical laborer or are training (exercising)
hard on a daily basis, once you become fat-adapted, you
probably don't ever need to consume more than 150 grams of dietary
carbs – and you can probably thrive on far less.
Many Pbers [Mark's diet, Primal Blueprint] do very well (including
working out) on 30-70 grams a day." [Emphasis
Replace Carbs with Healthful Fats
As I see it,
this is really a non-issue for most people as few people anywhere
near Dr. Jaminet's recommendation of cutting carbs from the standard
50 percent down to 20-30 percent of total calories. However,
if you've already begun to seriously address your carb intake then
you may want to experiment with various amounts of "safe carbs"
like rice and potatoes. As Mark describes, the actual amount of
carbs could vary anywhere from 30 to 150 grams a day, depending
on whether your body has adapted to burning ketones and your level
Keep in mind
that when we're talking about harmful carbs, we're only referring
to grains and sugars, NOT vegetable carbs.
When you cut
grain/sugar carbs you actually need to radically increase the amount
of vegetables you eat since, by volume, the grains you need to trade
out are denser than vegetables. You also need to dramatically increase
healthful fats such as avocados, coconut oil, egg yolks, raw grass
fed organic butter, olives and nuts.
You would not
want to use highly processed and genetically engineered omega-6
oils like corn, canola and soy as they will upset your omega 6/3
ratio. Of course you want to avoid all trans fats, but contrary
to popular advice, saturated fats are a key component of a healthy
diet that will promote weight loss.
goal will be to have as much as 50-70 percent of your diet as
healthy fat, which will radically reduce your carbohydrate
intake. It can be helpful to remember that fat is far more satiating
than carbs, so if you have cut down on carbs and feel ravenous,
this is a sign that you have not replaced them with sufficient amounts
of healthy fat. Sources of healthy fats that you'll want to add
to your diet include:
oil (for cold dishes)
oil (for all types of cooking and baking)
made from raw grass-fed organic milk
Nuts, such as, almonds or pecans
pastured egg yolks
organic nut oils
will likely notice massive improvement in their health by following
this approach as they are presently consuming FAR more grain and
bean carbohydrates in their diet, and any reduction will
be a step in the right direction. To help you get started on the
right track, review my Nutritional
Plan, which guides you through these dietary changes one step
at a time.
Confirms Benefits of Low-Carb/High-Fat Diet
advice has focused on low-fat diets for weight loss and heart disease
prevention, but again and again, studies demonstrate that this advice
is diametrically opposed to reality... In one such study, researchers
at Johns Hopkins University School of Medicine's Heart and Vascular
Institute compared the effects of two diets on vascular health;
one low in fat, the other low in carbs. The study in question was
presented at this year's meeting of the American College of Sports
Medicine in Denver, on June 33.
The study included
a total of 46 men and women weighing on average 218 pounds. The
six-month long weight loss program consisted of moderate aerobic
exercise and strength training, and one of two diets, either:
high-fat: Less than 30 percent of calories from carbs
(pastas, breads and sugary fruits), and up to 40 percent from
fats (meat, dairy products, and nuts)
high-carb diet: Less than 30 percent of calories from
fat, and 55 percent from carbs
group on average shed 10 pounds in 45 days, while the low-fat group
took 70 days to lose the same amount of weight. In terms of vascular
health, the low-carb, high-fat dieters showed no harmful vascular
changes, which is the primary reason for why so many are afraid
of high-fat diets.
the lead investigator, professor of medicine and director of clinical
and research exercise physiology, Kerry Stewart, Ed.D:
should help allay the concerns that many people who need to lose
weight have about choosing a low-carb diet instead of a low-fat
one, and provide re-assurance that both types of diet are effective
at weight loss and that a low-carb approach does not seem to pose
any immediate risk to vascular health. More people should be considering
a low-carb diet as a good option."
believes that the emphasis on low-fat diets has likely contributed
to the obesity epidemic in the US by promoting overconsumption of
sugars and grains. I couldn't agree more. The simple reason for
this is that grains and sugars raise your insulin levels, which
causes insulin resistance and, ultimately, weight gain, diabetes,
and heart disease.
is quite clear that chronically raising your blood glucose through
consumption of grains and sugars will increase your insulin resistance,
which in turn will increase insulin and leptin resistance. And avoiding
insulin and leptin resistance is perhaps the single most important
factors if you seek optimal health and longevity.
the degree to which you choose to reduce carbs however
is, ultimately, up to you. And certain individual biochemical differences
can make one diet more beneficial for you than others. The key point
is to be aware that consuming sugar, grains and starches will promote
insulin resistance to some degree or other, depending on
the amount you consume.
remember to listen to your body as it will give you feedback if
what you are doing is right for your unique biochemistry and genetics.
So listen to that feedback and adjust your program accordingly.
[+] Sources and References
2012 Dr. Joseph Mercola
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