lowering of metabolism after weight loss
 

A while ago there was some discussion on if the body adjusts metabolism
after weight loss to maintain the higher weight. Here's an article that
talks about the issue:

Why lost weight returns after dieting
http://www.news-medical.net/?id=2955

The data suggests that weight loss in obese, obesity-prone rats, induced
by caloric restriction, is accompanied by metabolic adaptations that
predispose one to regain the lost weight. In rats that are losing
weight, this is exhibited by a significant reduction in metabolic rate,
measured as both 24-hour energy expenditure and sleeping metabolic rate,
both independent of metabolic mass and energy intake. This adaptation
persists after eight weeks of intake-regulated weight maintenance, but
is no longer present with eight subsequent weeks of feeding at-will
where rats are regaining lost weight. While rats that are regaining
weight may have a shift in appetite that would contribute to their high
rate of weight regain, the drive to increase food intake remains the
most critical factor in the predisposition to regain lost weight. This
adjustment clearly weighs more on the energy balance equation than the
metabolic adjustment on energy expenditure observed in this or any other
study.

Additionally, the effect that energy intake, or more particularly,
carbohydrate intake, has on respiratory quotient [dividing the amount of
CO2 produced (VCO2) by the amount of oxygen uptake (VO2)]. RQ is much
more dramatic than the metabolic adjustment observed from weight
reduction. This drive to increase food intake likely involves
environmental stimuli (diet composition, food palatability, physical
activity) influencing motivational and metabolic components of a
genetically determined set of central systems.

While the data suggest that these metabolic adaptations might hinder
successful weight maintenance, it should not imply that successful
weight maintenance is unachievable. Even with the increased intake of
carbohydrates, regular physical exercise may be the key factor that
counteracts these metabolic adaptations to weight loss.

----

I notice that after everyone of these pronouncements saying how hard
weight is to lose they say something like it's not unachievable. How
hard does something have to be before people stop trying to achieve it?
Not very hard.

regular physical exercise may be the key factor that counteracts these
metabolic adaptations to weight loss.


for me its the only way to do it.

--
Tom
Exercise Today = Life Tomorrow

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----

I notice that after everyone of these pronouncements saying how hard
weight is to lose they say something like it's not unachievable. How hard
does something have to be before people stop trying to achieve it?
Not very hard.

Ignoramus21798 wrote:
It all depends on how much you want it.

So if you want it bad enough you can be a four minute miler? I think
not. Your physical body establishes what is ultimately possible.

Numerous people lose weight
and keep it off, not without difficulties. It is not impossible.

Nor is it easy enough to expect even the majority of people to be able
to do it.

On 4/14/2005 2:55 PM, wendy wrote:
Numerous people lose weight
and keep it off, not without difficulties. It is not impossible.


Nor is it easy enough to expect even the majority of people to be able
to do it.

Don't you think that the majority of people *diet* rather than have a
lifestyle change? I agree that people who think, "I will go on this
diet until I am a size X." Then when they become a size X, "Woo Hoo.
GOAL BABY! Now I can EAT whatever I WANT." If that is the person's
mindset, of course they will most likely be on a rollercoaster.

OTOH, if people go into this thinking, in order to be more healthy, I
should eat X and exercise Y, I do feel that they will have long term
success. It's all about the mindset/attitude.

--
jmk in NC

Ignoramus21798 wrote:
On Thu, 14 Apr 2005 11:55:30 -0700, wendy wrote:

Ignoramus21798 wrote:

It all depends on how much you want it.

So if you want it bad enough you can be a four minute miler? I think
not. Your physical body establishes what is ultimately possible.


Any fat person can lose weight if they are calorie restricted (for
example, confined in a cage with limited food). It is unlike running.

That's not really the point though. What is important is how do you keep
the weight off when you are free in the wild.


Surely, we know that the majority of people cannot lose weight, and
the majority of those who can lose weight does not keep it off. So,
here, I agree with you.

I don't know about cannot, but it's a lot harder than people want to admit.

jmk wrote:
OTOH, if people go into this thinking, in order to be more healthy, I
should eat X and exercise Y, I do feel that they will have long term
success. It's all about the mindset/attitude.

But it's not. It's more about how our bodies are. Just like running.
You'll never be as fast as person with a lot of fast twitch muscle
fibres. Clearly to be a world class athelete requires an immense amount
of work and steroids, but it's difficult to overcome your genetic heritage.

If you are born with fewer dopamine receptors you are much more likely
to be an addict and/or overweight. Plus a dozen other hormone
interactions that are genetic. Plus the instinct to eat in our fat/sugar
environment. Plus we don't need to exercise to survive anymore.

To say it's all about mindset is to not really understand what's going on.

"wendy" wrote in message
...
jmk wrote:
OTOH, if people go into this thinking, in order to be more healthy, I
should eat X and exercise Y, I do feel that they will have long term
success. It's all about the mindset/attitude.

But it's not. It's more about how our bodies are. Just like running.
You'll never be as fast as person with a lot of fast twitch muscle fibres.
Clearly to be a world class athelete requires an immense amount of work
and steroids, but it's difficult to overcome your genetic heritage.

If you are born with fewer dopamine receptors you are much more likely to
be an addict and/or overweight. Plus a dozen other hormone interactions
that are genetic. Plus the instinct to eat in our fat/sugar environment.
Plus we don't need to exercise to survive anymore.

To say it's all about mindset is to not really understand what's going on.

But broadly speaking, we are all the same - at each end there are extremes -
supreme atheletes at one end and at the other there are the people with a
major lack of dopamine receptors or whatever, but the vast vast bulk of us
are averagely in the middle.

Not sure about this rat thing anyway - they didn't have to think about
whether they want to gain, lose or maintain weight. The psychological thing
is too important to be ignored.

Rachael
176/118/111

"wendy" wrote in message
...
Ignoramus21798 wrote:
On Thu, 14 Apr 2005 11:55:30 -0700, wendy wrote:

Ignoramus21798 wrote:

It all depends on how much you want it.

So if you want it bad enough you can be a four minute miler? I think
not. Your physical body establishes what is ultimately possible.


Any fat person can lose weight if they are calorie restricted (for
example, confined in a cage with limited food). It is unlike running.

That's not really the point though. What is important is how do you keep
the weight off when you are free in the wild.


Surely, we know that the majority of people cannot lose weight, and
the majority of those who can lose weight does not keep it off. So,
here, I agree with you.

I don't know about cannot, but it's a lot harder than people want to
admit.

Well...it's not rocket science either. Losing weight simply requires
consuming a few less calories per day than one burns.

That said, in today's world where calorie-dense food is ever present in
enormous quantities, and where most of us spend most of our days sitting on
our rear ends, it does require a degree of dedication to lose weight.

As with many other things in life, anything that requires patience and
persistence will tend to have a low rate of success. It's just a lot easier
for most people to reach for the bag of snacks and the remote control,
rather than get up off the couch and go for a walk. But, that's more an
issue of personal priorities than metabolism.

GG

"wendy" wrote in message
...
jmk wrote:
OTOH, if people go into this thinking, in order to be more healthy, I
should eat X and exercise Y, I do feel that they will have long term
success. It's all about the mindset/attitude.

But it's not. It's more about how our bodies are. Just like running.
You'll never be as fast as person with a lot of fast twitch muscle
fibres. Clearly to be a world class athelete requires an immense amount
of work and steroids, but it's difficult to overcome your genetic
heritage.

If you are born with fewer dopamine receptors you are much more likely
to be an addict and/or overweight. Plus a dozen other hormone
interactions that are genetic. Plus the instinct to eat in our fat/sugar
environment. Plus we don't need to exercise to survive anymore.

To say it's all about mindset is to not really understand what's going on.

No offense, but it sounds like you are in search of excuses.

GG

"wendy" wrote in message
...

A while ago there was some discussion on if the body adjusts metabolism
after weight loss to maintain the higher weight. Here's an article that
talks about the issue:

Why lost weight returns after dieting
http://www.news-medical.net/?id=2955

The data suggests that weight loss in obese, obesity-prone rats, induced
by caloric restriction, is accompanied by metabolic adaptations that
predispose one to regain the lost weight. In rats that are losing
weight, this is exhibited by a significant reduction in metabolic rate,
measured as both 24-hour energy expenditure and sleeping metabolic rate,
both independent of metabolic mass and energy intake. This adaptation
persists after eight weeks of intake-regulated weight maintenance, but
is no longer present with eight subsequent weeks of feeding at-will
where rats are regaining lost weight. While rats that are regaining
weight may have a shift in appetite that would contribute to their high
rate of weight regain, the drive to increase food intake remains the
most critical factor in the predisposition to regain lost weight. This
adjustment clearly weighs more on the energy balance equation than the
metabolic adjustment on energy expenditure observed in this or any other
study.

Additionally, the effect that energy intake, or more particularly,
carbohydrate intake, has on respiratory quotient [dividing the amount of
CO2 produced (VCO2) by the amount of oxygen uptake (VO2)]. RQ is much
more dramatic than the metabolic adjustment observed from weight
reduction. This drive to increase food intake likely involves
environmental stimuli (diet composition, food palatability, physical
activity) influencing motivational and metabolic components of a
genetically determined set of central systems.

While the data suggest that these metabolic adaptations might hinder
successful weight maintenance, it should not imply that successful
weight maintenance is unachievable. Even with the increased intake of
carbohydrates, regular physical exercise may be the key factor that
counteracts these metabolic adaptations to weight loss.

----

I notice that after everyone of these pronouncements saying how hard
weight is to lose they say something like it's not unachievable. How
hard does something have to be before people stop trying to achieve it?
Not very hard.

That study reduced the rat's food intake rather drastically. Specifically,
"weight loss was induced by limiting calories to approximately 60 percent of
energy expenditure". This would be equivalent to a person who burns 2500
calories per day being limited to only 1500 calories per day.

There's also the issue of time frame. In the experiment, they took 16 weeks
to allow the rats to gain 10-15% body weight. But, they allowed only 2
weeks to reduce their body weight by that much.

It's possible the effect on metabolism seen in those rats was due to a
"starvation" response. If they had lost weight the weight slowly (the same
way they had gained it), it's possible the effect on metabolism would have
been different.

--
GG
http://www.WeightWare.com
Your Weight and Health Diary