Want To Rev-Up Your Fat-Burning?
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Story at-a-glance
- It’s long
been known that restricting calories in certain animals can increase
their lifespan by as much as 50 percent, but more recent research
suggests that sudden and intermittent calorie restriction appears
to provide the same health benefits as constant calorie restriction,
which may be helpful for those who cannot successfully reduce
their everyday calorie intake - Mice that
fasted for 16 hours a day stayed lean and healthy even when fed
a high-calorie diet; their mouse counterparts that had access
to food day and night became obese and showed blood sugar and
liver problems despite eating the same number of calories - Three major
mechanisms by which fasting benefits your body, as it extends
lifespan and protects against disease, include increased insulin
sensitivity and mitochondrial energy efficiency; reduced oxidative
stress; and increased capacity to resist stress, disease and aging - In a recent
paper, a team of researchers identified seven obesity-related
myths, six assumptions, and nine evidence-supported facts “relevant
for the formulation of sound public health, policy, or clinical
recommendations.†However, many of the items listed as myths and
presumptions are simply common-sense guidelines that can help
you maintain a healthier lifestyle, which will inevitably form
the foundation of good health, while many of the “evidence-supported
facts†listed actually make for poor public health policy
Is it a good
idea to “starve†yourself just a little bit each day?
The evidence suggests that yes, avoiding eating around the clock
could have a very beneficial impact on your health and longevity.
What we’re
talking about here is generally referred to as intermittent
fasting, which involves timing your meals to allow for regular
periods of fasting.
It takes about
six to eight hours for your body to metabolize your glycogen stores
and after that you start to shift to burning fat. However, if you
are replenishing your glycogen by eating every eight hours (or sooner),
you make it far more difficult for your body to use your fat stores
as fuel.
It’s long
been known that restricting calories in certain animals can increase
their lifespan by as much as 50 percent, but more recent research
suggests that sudden and intermittent calorie restriction appears
to provide the same health benefits as constant calorie restriction,
which may be helpful for those who cannot successfully reduce their
everyday calorie intake (or aren’t willing to).
Unfortunately,
hunger is a basic human drive that can’t be easily suppressed,
so anyone attempting to implement serious calorie restriction is
virtually guaranteed to fail. Fortunately you don’t have to
deprive yourself as virtually all of the benefits from calorie restriction
can be achieved through properly applied intermittent fasting.
Three Major
Mechanisms by which Fasting Benefits Your Health
While fasting
has long gotten a bum rap for being one of the more torturous ways
to battle the bulge, it really doesn’t have to be an arduous
affair. We’re NOT talking about starving yourself for days
on end. Simply restricting your daily eating to a narrower window
of time of say 6-8 hours, you can reap the benefits without the
suffering. This equates to 16-18 hours worth of fasting each and
every day — enough to get your body to shift into fat-burning
mode.
Many studies
have evaluated daily intermittent fasting, and the results are compellingly
positive. Three major mechanisms by which fasting benefits your
body, as it extends lifespan and protects against disease, include:
- Increased
insulin sensitivity and mitochondrial energy efficiency
– Fasting increases insulin sensitivity along with mitochondrial
energy efficiency, and thereby retards aging and disease, which
are typically associated with loss of insulin sensitivity and
declined mitochondrial energy. - Reduced
oxidative stress – Fasting decreases the accumulation
of oxidative radicals in the cell, and thereby prevents oxidative
damage to cellular proteins, lipids, and nucleic acids associated
with aging and disease. - Increased
capacity to resist stress, disease and aging –
Fasting induces a cellular stress response (similar to that induced
by exercise) in which cells up-regulate the expression of genes
that increase the capacity to cope with stress and resist disease
and aging.
Is Daily
Fasting the Key to Permanent Weight Loss?
As reported
by George Dvorsky1
in a recent article, one of the most important studies in support
of daily intermittent fasting was published just last year by biologist
Satchidananda Panda and colleagues at Salk’s Regulatory Biology
Laboratory. They fed mice a high-fat, high-calorie diet but
altered when they were able to eat.
One group
had access to food both day and night, while the other group had
access to food for only eight hours at night (the most active period
for mice). In human terms, this would mean eating only for 8 hours
during the day. Despite consuming the same amount of calories, mice
that had access to food for only eight hours stayed lean and did
not develop health problems like high blood sugar or chronic inflammation2.
They even had improved endurance motor coordination on the exercise
wheel. The all-day access group, on the other hand, became obese
and were plagued with health problems including:
- High cholesterol
- High blood
sugar - Fatty liver
disease - Metabolic
problems
This suggests
that your body may benefit from the break it receives while fasting,
whereas constant eating may lead to metabolic exhaustion and health
consequences like weight gain. Researchers said their latest work
shows it’s possible to stave off metabolic disease by simply restricting
when you eat with periodic fasting, or even by just keeping to regular
meal schedules rather than “grazing” off and on all day. They concluded:
“[Time-restricted
feeding] is a nonpharmacological strategy against obesity and associated
diseases.”
What the
Research Says about Intermittent Fasting
Dvorsky highlights
other research into fasting that point to similar conclusions, such
as:
- Research
by Valter Longo3
at the University of Southern California’s Longevity Institute
shows that intermittent fasting has a beneficial impact on IGF-1,
an insulin-like growth factor that plays a role in aging. When
you eat, this hormone drives your cells to reproduce, and while
this is good for growth, it’s also a factor that drives
the aging process. Intermittent fasting decreases the expression
of IGF-1, and switches on other DNA repair genes. In this way,
intermittent fasting switches your body from “growth modeâ€
to “repair mode.†- Krista Varady
with the University of Illinois has been researching the impact
of fasting on chronic diseases like cardiovascular disease, type
2 diabetes, and cancer. Her work also compares the effects of
intermittent fasting with caloric restriction, which is known
to benefit health and longevity. Animal studies using alternate-day
fasting4
have shown it lowers the risk of diabetes, at rates comparable
to caloric restriction. Alternate-day fasting has also been shown
to reduce cancer rates by reducing cell proliferation. - Research
by Mark Hartman and colleagues5
indicates short-term fasting can trigger production of human growth
hormone (HGH) in men, and reduce oxidative stress that contributes
to disease and aging; benefits brain health, mental well-being,
and clarity of thought
Review Debunks
Myths about Weight Loss, Obesity
Intermittent
fasting is one of the latest weight management strategies to get
a lot of press. Meanwhile, other weight loss myths are being debunked.
Dr. David B. Allison, director of the Nutrition Obesity Research
Center at the University of Alabama, and colleagues recently published
a paper on Myths, Presumptions, and Facts about Obesity6,
stating:
“Many
beliefs about obesity persist in the absence of supporting scientific
evidence (presumptions); some persist despite contradicting evidence
(myths). The promulgation of unsupported beliefs may yield poorly
informed policy decisions, inaccurate clinical and public health
recommendations, and an unproductive allocation of research resources
and may divert attention away from useful, evidence-based information.â€
The team identified:
- Seven
obesity-related myths concerning the effects of small
sustained increases in energy intake or expenditure, establishment
of realistic goals for weight loss, rapid weight loss, weight-loss
readiness, physical-education classes, breast-feeding, and energy
expended during sexual activity. These include: - Small
things make a big difference. Walking a mile a day can lead
to a loss of more than 50 pounds in five years. - Set a
realistic goal to lose a modest amount. - People
who are too ambitious will get frustrated and give up. - You have
to be mentally ready to diet or you will never succeed. - Slow and
steady is the way to lose. If you lose weight too fast, you
will lose less in the long run. - Six
presumptions that have yet to be proven true or false
about the effects of regularly eating breakfast, early childhood
experiences, eating fruits and vegetables, weight cycling, snacking,
and the built (i.e., human-made) environment, such as: - Diet and
exercise habits in childhood set the stage for the rest of life. - Add lots
of fruits and vegetables to your diet to lose weight or not
gain as much. - Yo-yo
diets lead to increased death rates. - People
who snack gain weight and get fat. - If you
add bike paths, jogging trails, sidewalks and parks, people
will not be as fat.       - Nine
evidence-supported facts that are relevant for the formulation
of sound public health, policy, or clinical recommendations, including: - Heredity
is important but is not destiny. - Exercise
helps with weight maintenance. - Weight
loss is greater with programs that provide meals. - Some prescription
drugs help with weight loss and maintenance. - Weight-loss
surgery in appropriate patients can lead to long-term weight
loss, less diabetes and a lower death rate
What I feel
is missing here is the focus on an all-around healthy lifestyle
pattern. Can you lose weight on prescription drugs? Yes. Does the
research support this as “fact� Yes. But this does
NOT automatically mean that recommending diet drugs is good public
health policy! Will diet drugs have a beneficial impact on your
health in the long run? Do potential side effects of the drugs outweigh
the benefit of losing weight?
Ditto for
bariatric
surgery. Does it lead to weight loss? Yes! But the side effects
can be severe, including death, and several studies have shown the
long-term outcome in terms of overall health is not that great…
Some of the
items listed as myths and presumptions are simply common-sense guidelines
and “helpful tips†that can help you maintain a healthier
lifestyle, which will inevitably form the foundation of good health.
So I would advise you to differentiate between “established
scientific fact†(such as: weight loss surgery leads to weight
loss) and what amounts to holistic healthy lifestyle guidelines,
as the two are not necessarily interchangeable.
If your goal
is to promote health, then supporting the addition of bike paths
in your communities is not a crazy idea at all. In fact, some of
these myths and presumptions are sort of silly, as when you talk
about things like “can adding jogging trails and parks promote
healthier weight?†You also have to consider the fact that
there is social conditioning at work, and people have to start to
rethink how they live their daily lives in order to see a change.
This can take time. Having a public policy that tells you to get
bariatric surgery instead of going for a walk every day is nothing
short of crazy if you really think about it…
Clinical
Trial to Be Conducted to Test Whether Skipping Breakfast Leads to
Weight Loss
According
to the New York Times7:
“…
people often rely on weak studies that get repeated ad infinitum.
It is commonly thought, for example, that people who eat breakfast
are thinner. But that notion is based on studies of people who happened
to eat breakfast. Researchers then asked if they were fatter or
thinner than people who happened not to eat breakfast — and
found an association between eating breakfast and being thinner.
But such studies can be misleading because the two groups might
be different in other ways that cause the breakfast eaters to be
thinner. But no one has randomly assigned people to eat breakfast
or not, which could cinch the argument.
… The
question is: ‘Is it a causal association?’ To get the
answer, he added, ‘Do the clinical trial.’
He decided
to do it himself, with university research funds. A few hundred
people will be recruited and will be randomly assigned to one of
three groups. Some will be told to eat breakfast every day, others
to skip breakfast, and the third group will be given vague advice
about whether to eat it or not.”
Is Intermittent
Fasting Right for You?
If you’re
already off to a good start on a healthy diet and fitness plan,
then intermittent fasting might be just the thing to bring you to
the next level. However, you need to pay careful attention to your
body, your energy levels, and how it makes you feel in general.
Please keep
in mind that proper nutrition becomes even MORE important when fasting,
so addressing your diet really should be your first step. Common
sense will tell you that fasting combined with a denatured, highly
processed, toxin-rich diet is likely to do more harm than good,
as you’re not giving your body proper fuel to thrive when you DO
eat.
If you’re
hypoglycemic, diabetic, or pregnant (and/or breastfeeding), you are
better off avoiding any type of fasting or timed meal schedule until
you’ve normalized your blood glucose and insulin levels, or weaned
the baby. Others categories of people that would be best served
to avoid fasting include those living with chronic stress, and those
with cortisol dysregulation.
Signs and
Symptoms of Hypoglycemia
Hypoglycemia
is a condition characterized by an abnormally low level of blood
sugar. It’s commonly associated with diabetes, but you can be hypoglycemic
even if you’re not diabetic. Common symptoms of a hypoglycemic crash
include:
- Headache
- Weakness
- Tremors
- Irritability
- Hunger
As your blood
glucose levels continue to plummet, more severe symptoms can set
in, such as:
- Confusion
and/or abnormal behavior - Visual disturbances,
such as double vision and blurred vision - Seizures
- Loss of
consciousness
One of the
keys to eliminating hypoglycemia is to eliminate sugars, especially
fructose from your diet. It will also be helpful to eliminate grains,
and replace them with higher amounts of quality proteins and healthful
fats. However it will take some time for your blood sugar to normalize.
You’ll want to pay careful attention to hypoglycemic signs and symptoms,
and if you suspect that you’re crashing, make sure to eat something.The
ideal food would be coconut oil as it will not worsen your insulin
levels and is metabolized relatively quickly for energy. You can
try some coconut
candy, for example. Ideally, you should avoid fasting if you’re
hypoglycemic, and work on your overall diet to normalize your blood
sugar levels first. Then try out one of the less rigid
versions of fasting and work your way up.
Fasting While
Pregnant is Not a Good Idea…
As for pregnant
and/or lactating women, I don’t think fasting would be a wise choice.
Your baby needs plenty of nutrients, during and after birth, and
there’s no research supporting fasting during this important time.
On the contrary, some studies8
suggest it might be contraindicated, as it can alter fetal breathing
patterns, heartbeat, and increase gestational diabetes. It may even
induce premature labor. I don’t think it’s worth
the risk.
Instead, my
recommendation would be to really focus on improving your nutrition
during this crucial time. A diet with plenty of raw organic, biodynamic
foods, and foods high in healthful fats, coupled with high quality
proteins will give your baby a head start on good health. You’ll
also want to be sure to include plenty of cultured and fermented
foods to optimize your — and consequently your baby’s —
gut flora. For more information, please see this previous article
that includes specific dietary recommendations for a healthy
pregnancy, as well as my interview with Dr.
Natasha Campbell-McBride.
Finding a
Lifestyle Plan that Works for You Requires Trial and Error
While intermittent
fasting can provide valuable health benefits, remember that fasting
does not mean abstaining from ALL food for extended periods of time.
Rather it involves a dramatic reduction of calorie intake at
regular intervals — whether you opt for a 16, 20, or
24 hour fast once or twice a week, or fasting every other day, or
simply delaying certain meals, such as skipping breakfast.
Just remember,
it takes about six to eight hours for your body to metabolize your
glycogen stores and only after that do you start to shift
to burning fat, but only if you are already adapted to burning fat
by having your fat burning enzymes upregulated by the strategy discussed
above, which takes anywhere from a few weeks to a few months, depending
on how healthy you are.
Always listen
to your body, and go slow; work your way up to 16-18 hour fasts
if your normal schedule has included multiple meals a day. Also
be sure to address any hypoglycemic tendencies, as it can get increasingly
dangerous the longer you go without eating to level out your blood
sugar.
If you have
already addressed your diet, cutting out fructose and grains and
replacing them with healthful fats, then intermittent fasting could
further boost weight loss and provide additional health benefits.
If you’re engaged in a regular fitness program and feel like
you’ve hit a plateau, then working out in a fasted state might
help rev things up. For more information about exercise while fasting,
please see this previous article.
Sources and
References
1
iO9.com January 28, 2013
2
Cell Metabolism June 6, 2012: 15(6); 848-860
3
V. D. Longo – Evidence for Programmed Aging
4
American Journal of Clinical Nutrition July 2007: 86(1); 7-13
5
Journal of Clinical Endocrinology and Metabolism 1991:74(4); 757-765
(PDF)
6
New England Journal of Medicine 2013; 368:446-454
7
New York Times January 30, 2013
8
Marks Daily Apple February 22, 2012
March
18, 2013
Copyright ©
2013 Dr. Joseph Mercola