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Q: Diets don't work, why? ( Answered 5 out of 5 stars,   1 Comment )
Subject: Diets don't work, why?
Category: Miscellaneous
Asked by: qpet-ga
List Price: $40.00
Posted: 28 Jan 2003 07:09 PST
Expires: 27 Feb 2003 07:09 PST
Question ID: 149504
Diets don't work, why? What are the physiological and psychological aspects? 
Are there different theories out there? Short summary please.

Request for Question Clarification by tutuzdad-ga on 28 Jan 2003 07:44 PST
Considering your opening statement: "Diets don't work, why?"

Are you requiring research that supports only this school of thought,
or are you also open to the argument that some diets are, in fact,
quite successful?


Clarification of Question by qpet-ga on 28 Jan 2003 09:53 PST
Good point,howerver the pervailing view is that after one year 95% of
individuals gain their weight back (and sometimes more). Why?
Subject: Re: Diets don't work, why?
Answered By: bobbie7-ga on 28 Jan 2003 22:29 PST
Rated:5 out of 5 stars
Hello Qpet,

“National Institutes of Health and other studies show that 98% of
people who lose weight gain it back within five years. And 90% of
those gain back more weight than they lost. The failure of weight loss
programs is so great that a leading researcher has said, "Dieting is
the leading cause of obesity in the US."

I compiled the most important physiological and psychological aspects
of the failure of diets in the following links which include short
excerpts and summaries to relevant information addressing this topic.

According to Dr. Nikki Goldman diets don't work for two major reasons.
One is stress and the other is the “all or nothing” syndrome.

Diets “cause stress. Stress stimulates appetite. It also depletes the
necessary brain chemicals which keep us calm and energized. As a
result, we reach for food to replenish these substances. Because
carbohydrates such as pretzels, candy, and cookies supply these
quickly, we tend to reach for these snacks when we're stressed.
However, their affect is short lived. Before long, our brain exhausts
the supply and we are reaching for more.
The "all or nothing" syndrome brings us to our knees. We're either on
the diet, strict and rigid or totally off the diet diving into the
forbidden fruit, and ice cream, and chocolate, and chips, and cookies
and… When we fail at the diet, the pendulum swings to the complete
opposite side and we overindulge.”


Deanne Jade, the Principal of the National Centre of Eating Disorders
wrote an interesting article describing a number of psychological
aspects of the failure of diets which include then fact that diets
fail to address the emotional aspect of overeating and dieters usually
fail to change their core habits.

Diets are hard to do:

“Most diets involve a significant change in a person's normal eating
habits over an extended period of time. But habits die hard; we cling
to them because they fit in with our lifestyle and the people around
us. And changing something that is second nature to us very often
results in stress - especially if that change is at odds with the
habits of those in our social and family world.

Dieting is also hard because it relies on our willpower to keep us on
the right track. (..) Willpower is hard to maintain for extended
periods of time, especially if our dietary rules are too strict. (..)
Dieting is hard because people haven't learned the difference between
willpower and commitment to long-term behavior change.”

Diets make you feel hungry and deprived:

“..diets make you very hungry and create powerful cravings for the
very foods that dieters try to stay away from - such as sugars and
fats. On top of these cravings, dieters also have to manage feelings
of deprivation: 'Everybody is eating what I'm not allowed to. They can
have it - why cant I?' This kind of thinking is likely to lead to
rebellious overeating.”

Dieters lapse and collapse:

“Most people get bored with rigid eating plans and go off the rails
from time to time. The trouble is that for many people a lapse is a
sign of failure. They tell themselves they've 'blown it' and
experience feelings of inadequacy; (..)  Such people go from diet to
diet hoping to find the one that will stop them from failing, but such
a diet doesn't exist, and they may end up bigger than ever each time
they try.”

Diets fail to address the emotional aspect of overeating:

“.. some people gain weight because they turn to food for emotional
comfort or to cope with negative feelings like anger or loss. Dieting
doesn't solve the problem of 'emotional' eating. If anything, it makes
people more depressed - and losing weight will often make things
worse, as people have to cope with the pressures and expectations that
their new body shape can entail.”

Dieters usually fail to change their core habits:

The only people who lose weight and keep it off permanently are those
who have made permanent changes to their own eating and exercise
habits, and to those of their families. (..) Too often those old
eating habits will creep back in, no matter how much weight the dieter
has lost, and in time they'll find themselves back at square one.

Net Doctor: Why diets don't work


Diets also cause you to obsess with the one thing that you are trying
to avoid – food. Dr Ingrid van Heerden a registered dietician explains
it this way:

“When on a diet you are expected to plan out every aspect of what you
will eat.  What will you have for your next meal, how many calories it
will contain. You become so obsessed with food, you can barely think
of anything else. (..)  On top of it all you are depriving yourself of
calories, so you’re hungry irritable and obsessed with food.
It gets worse though. No diet allows the dieter to eat those foods
that his/her body really craves. You know, those foods that, the more
you get into your diet, the more you promise yourself you will treat
yourself with when you reach your target weight.  As sure as night
follows day, you will crack – you will binge – you will lay your hands
on as much of your favorite food that you can and scoff the lot. Then,
you feel bad, you feel like a failure, and chances are you will binge
again – just to try and get rid of that bad feeling.”

Some other reasons diets don’t work:

- “Diets rely on will power rather than addressing the underlying
thoughts, feelings and emotions that underpin being overweight.

- Diets generally make you hand over control of a central part of your
life to an external program – all your thinking is done for you by the
program. This results in you losing touch with your body, with your
hunger or lack there-of, and in your ability to manage one of your
most basic needs.

- Diets don’t really prepare you for being thin. Most overweight
people have a number of unresolved issues concerning their personal
image, their social role and their sexuality which may be frightening
them out of being thin.
- Many diets don’t encourage or teach exercise. Exercise is absolutely
essential in maintaining weight loss. If you cut your calorie intake,
your body responds (despite your being overweight) as though you were
starving and as a survival instinct your metabolic rate drops. One way
of stimulating your metabolic rate is through exercise.
- Diets are dictatorial and the child in every one of us will rebel
against the dictator at one time or another.”,11513.asp


In a study called the World War II study of conscientious objectors by
Keys et al, normal weight, non-dieting men were asked to restrict
their food intake for six months in order to lose 25% of their body

These were the consequences:

-“The men became focused on food and food related activities like
collecting recipes and pictures of food.
- They also grew irritable, apathetic, lost interest in sex and fought
with each other and their girlfriends.
- Another surprising effect was noted when the men could resume normal
eating. The previously normal eaters developed bingeing behaviors and
gorged themselves on appealing food.

- They lost touch with hunger and satiety signals. 
- Other studies have indicated similar results.

Nutritional News: Why Diets Fail You by Erin Pammer, RD March, 1997


A diet of less than 1000-1200 calories can cause the body to go into a
starvation like mode.

“The body lowers its metabolism rate and works to conserve rather than
burn calories. Crash dieting can change the body's composition. When
people lose weight they take off water, fat and muscle. Losing a high
proportion of muscle is bad because that's what helps burn the
calories in the first place. When people gain the weight back, it's
mostly as fat - making it much harder to lose the next time.”

CBC TV's Witness: December 5th, 2001


The Metabolism:

“Your body has a tricky survival mechanism - if you eat less, your
body thinks you have a shortage of food, and it starts to conserve
"energy" in the form of fat. This is why diets will always fail in the
long run - even if you cut enough calories to lose weight for a short
period of time, your body eventually adjusts so that you will start to
gain weight - even if you're taking in the same number of calories as
you were when you were losing weight!

When we starve ourselves involuntarily (famine) or voluntarily
(dieting), our body responds to this potential threat to survival by
decreasing our metabolism. Basically, this means that we slow down
until we need fewer calories to maintain our body's everyday processes
(our minimum daily requirement of calories decreases). In fact, if we
are habitually on diets, our metabolism will be chronically slow.”


Yo- Yo Dieting

Yo- Yo Dieting or Weight Cycling is one of the main reasons that diets
don’t work for the majority of women who have been dieting over the

“When you diet, it is easy to get caught in a terrible cycle. You go
on a diet, lose weight, go off your diet, gain weight, and go on
another diet. You are always losing and gaining weight. This is called
weight cycling, or yo-yo dieting. Each time you start a new diet, it
may be harder to lose weight and easier to gain it back. Your body may
adjust to having less food, and use less energy. You may even gain
extra weight between diets.”

Department of Health and Community Services, Government of
Newfoundland and Labrador


“When you don't eat enough your body thinks it needs more, so it
starts to save, it begins to store away what ever it can. Mostly FAT!
Your body makes fat cells to store it. This is called starvation or
survival mode. Your body needs some fat and fat cells, without any fat
in your body you would die.


Your body needs calories for energy. If you're dieting (low calorie)
and exercising, your body isn't burning fat, it's burning muscle!
Calories are converted to energy, energy is what burns fat out of the
fat cells or shrinks them. This is called metabolism. It's the rate at
which the body turns calories into energy.”

Healthy New Age


Sally Anderson in her article “Why Diets don’t work” summarizes the
reasons very nicely:

1. “Many diets cut food intake to about 1,000 calories per day.
Initially, people eating so few calories will lose weight; however,
when the body becomes aware of the shortage of caloric intake, the
metabolism will slow down. The slowing down of the metabolism acts as
a protective device to conserve fat when there begins to be a shortage
of food. You may be consuming fewer calories, but because the
metabolism has slowed down, you are burning fewer calories.

2. When you reduce your daily caloric intake to 1,000 calories or
below, your body will not receive the necessary nutrients for optimum
health. It then is forced into taking protein and other nutrients from
the bones and muscles. Muscle is metabolically active -- it has been
referred to as the furnace that burns fat. When muscle tissue is lost,
the body reduces its ability to burn calories, and more fat weight is

3. According to the U.S. National Institutes of Health (1992): "The
very act of dieting results in binge-eating behaviors. It is known
that the onset of binge behavior occurs only after the experience of

4. Diets are bound to fail when people use food to nurture their
emotional needs without addressing the emotional issues causing the

5. You can't continue a diet forever, and when you return to normal
eating patterns, the weight will begin its return.”

Personal MD: Why Diets Don’t Work by Sally Anderson

Lastly, diets don’t work because dieters always want quick results.

“A diet requires a long-term (lifetime) commitment to a rigorous
discipline of diet and exercise. It's a commitment that most people
cannot keep.”

According to Tarquin James of Weight Loss International, “the only
type of diet that is successful over the long-term is a change in
eating patterns incorporated into a proper lifestyle change. Any
changes in diet should be made gradually over a period of time.”

Search Criteria:

“diets don't work”
weight loss failure +reasons
why don't diets work?
physiological +dieting
psychological +dieting
Journal of the American Dietetic Association.

I hope this information meets your needs and I must say thatI enjoyed
researching this question as I have been on and off diets for most of
my life.

Best Regards,

Request for Answer Clarification by qpet-ga on 29 Jan 2003 10:57 PST
Hi bobbie7-ga,
You found the "usual" reasons- good job on that. I need more
information on the underlying physiological aspects like "setpoint"
"reversion to the mean?"
"homeostasis" and maybe comparisson to other systems.(Body
temperature, blood pressure,and others.-I don't know if you can find
anything on that, but give it a try). Maybe there are similarities to
other unwanted aspects like procrastinationor being late. I have a
sense that change is very hard and usualy temporary.
If you could "dig around" for a while and find something in that
direction, I would be happy to increase your fee (doubble?).
Good luck,

Clarification of Answer by bobbie7-ga on 29 Jan 2003 11:12 PST
Hi Qpet, 
I'll do some more research on what you mentioned in your clarification
request and see what I can dig up.

Clarification of Answer by bobbie7-ga on 29 Jan 2003 13:25 PST
There are several main theories on weight and weight control,

The nature of fat cells 
Set point theory


Some researchers think that up to 80% of your weight may be determined
by your genes.

The proof: “Studies of twins show that adult twins almost always end
up within seven pounds of each other--regardless of whether they grew
up in "skinny" or "fat" households.
Adopted children usually look like their biological rather than
adoptive parents, regardless of how they were raised.
What does this mean? It means that some people are simply going to be
big, no matter what.”

Metabolism - I have mentioned this is my original answer.

The Nature of Fat Cells 

“When you lose weight, you do not lose fat cells; instead, your fat
cells shrink. Once they become an average size, it is extremely
difficult to lose any more weight because the fat cells are never
actually lost.

People produce new fat cells when they are children, when they are
pregnant (obviously, women only) and when they have gained fifty
pounds or so.  Fat cells are created when one fat cell becomes too
large and so splits into two. Once gained, they are never lost (except
through liposuction).

This is one reason why it is so difficult for the very overweight to
ever become skinny: Even though their fat cells are all normal-sized,
they have a lot more of them than most people do.”

Set Point Theory

Set Point Theory says that a person's natural weight is set at birth,
like height or eye color, and there is little you can do to change it.

The Set Point is the weight range in which your body is programmed to
weigh and will fight to maintain that weight

“Many studies show that it is just as difficult for a person at their
normal weight to gain weight by overeating, as it is for them to lose
weight by dieting. The only way to overcome the natural set point is
by dieting; then your metabolism is reset and you can easily gain more
than your original set point. This is why so many thin people can eat
like crazy and not gain weight--their metabolism speeds up to process
the extra food.

This also means that it's pretty easy to stabilize your weight--just
eat what seems natural to you. Your body will automatically find its
own set point, and stay there. No more weight fluctuations.”

Settling Point Theory

The Settling point theory “criticizes Set Point Theory by pointing to
the population-wide weight-gain experienced lately, and says that
something besides dieting must be at fault here. Their culprit is fat.


..your fat produces enzymes. These enzymes help to digest fat. So in
essence, your fat is producing chemicals that help to digest any fat
you eat. Some people's fat produce more of these enzymes than other
people's. If your body produces a lot of these enzymes, then you can
eat a lot of fatty food and your body will just process it away.
However, some people's fat produces very little of these enzymes. If
they eat a lot of fat, it gets stored as body fat. This body fat will
then produce more of these enzymes, so that less of future fat intake
is stored as body fat, until eventually an equilibrium is reached.
Their theory is that one's settling point can be influenced by the
amount of fat in one's diet. But still, some people are going to end
up bigger.”

An outline on Homeostasis - Eating & Hunger 

Homeostasis is Body Weight Regulation

Set point theories:
- Glucostatic theory: We eat when our blood glucose level falls below
a set point and stop eating when it returns to the set point
- Lipostatic theory: Deviations from set point for body fat cause
adjustments in levels of eating to return body fat to its set point

Evidence against set-point theories:
- Not evolutionarily sensible - Better to prevent energy deficit than
react to one
- Typical reductions in glucose or body fat don’t increase eating
- Preloading doesn’t reduce meal size
- Do not account for other experimentally verified causes of hunger &

Positive Incentive Theory:
-We eat out of habit and because we have evolved to enjoy eating

Set Point Theory of Weight:
- The body attempts to maintain a body-fat set point

Supporting evidence:
-Body weight tends to remain constant
-After dieting, individuals tend to return to pre-diet weight

Contrary evidence:
Body weight can and does change
Food deprivation improves health (set point should be optimal,
but isn’t)
The brain regulates fat levels through efficiency of energy use,
not through diet

Department of Psychology: Florida International University

Here are a number of excerpts taken from an essay on what is meant by
the term homeostasis?

“Homeostasis keeps the body’s temperature at a certain level (36.5oC)
and it keeps the pH of the body at a certain level so that enzymes
don’t denature. Blood glucose is kept constant, CO2 levels and O2
levels are monitored to ensure that enough oxygen and not too much
carbon dioxide are in the blood. The overall concentration and volume
of blood is also monitored homeostatically.”

Temperature control mechanism: 

“Humans maintain body temperature within 1oC of 36.5. If the
temperature rises too high, the resulting increase in blood
temperature is detected by receptors in the hypothalamus in the brain.
The heat loss centre also in the hypothalamus sends impulses to
arteries and sweat glands which eventually results in a fall in
temperature. Cold conditions are detected by receptors in the skin.”


“Hunger is an important homeostatic function as it tells us when to
eat and when to stop eating. The role of the mouth in hunger was
studied by Spiegel (1973). He asked participants to swallow a tube
that delivered food directly to the stomach. The intake was
established so that it maintained body weight but the meals weren’t
satisfying, the participants wanted to taste and chew the food. This
implied that the taste and sensation of the food in the mouth are
important in the regulation of meal size but not essential features.

The Glucostatic hypothesis:
“The Glucostatic hypothesis says that the levels of glucose in the
bloodstream determine how hungry we are. Neurons detect the level of
glucose in the body, they are situated in the hypothalamus, the blood
vessels and other organs. If the glucose level in the body drops and
no more food is available then the liver releases more (this is stored
in the liver in the form of glycogen).”

The Lipostatic hypothesis:

“The Lipostatic hypothesis (Nisbett, 1972) states that the body
monitors food intake by detecting how much fat (lipid) there is in the
blood. Everyone has a set body weight that they can not stray very far
from. It has been shown that as the proportion of fats in the body
decreases, hunger increases (Hoebel and Teitelbaum, 1966). According
to Keesey (1966) when the body fat gets too low people start to eat
and when it gets too high they stop eating. It has been proposed that
the set point weight is determined at or soon after birth by the
number of fat cells in the body. Weight is changed by the size of the
fat cells. This hypothesis suggests that damage to the hypothalamus
can indirectly shifty the body’s set point.”

Conclusion: The nervous system’s involvement in the regulation of
hunger is a little doubtful. The theories above have supporting and
contradictory evidence.

UK EssayBank

“Our brain receives signals (e.g. leptin) about our caloric reserves
in fat, and then co-ordinates behavioral and physiological mechanisms
which enable us to conserve energy in times of hardship. This is an
example of homeostasis - we try to defend decreases in body weight to
maintain a set point.”

Fran Ebling: Body weight research program

George Bray's Nutrient Balance Hypothesis:

“.. he refers to as a "sympathetic model of homeostasis". The essence
of this theory is that peptides that regulate appetite also regulate
sympathetic activity (thermogenesis). Specifically, peptides that
decrease appetite tend to INCREASE thermogenesis. The reverse is also
true: peptides that increase appetite tend to DECREASE thermogenesis.”

Neuropeptide Y increases carbohydrate intake.
Galanin increases fat intake.
Growth hormone-releasing hormone increases protein intake. 


“Thus, whether an obese person is hyperphagic (large eater) would
depend on their mix of peptide imbalances. An excess of peptides that
primarily reduce thermogenesis would explain why many obese people do
not have large appetites. The greater ones obesity, the greater the
biochemical (peptide, enzyme, etc.) imbalances. This is true whether
one is hyperphagic or not. The sum of these biochemical imbalances
determines how high your set point is.”

Homeostasis and Negative Feedback

Homeostasis refers to the maintenance of the internal environment
within tolerable limits.

“All sorts of factors affect the suitability of our body fluids to
sustain life; these include properties like temperature, salinity,
acidity, and the concentrations of nutrients and wastes. Because these
properties affect the chemical reactions that keep us alive, we have
built-in physiological mechanisms to maintain them at desirable
When a change occurs in the body, there are two general ways that the
body can respond.

“In negative feedback, the body responds in such a way as to reverse
the direction of change. Because this tends to keep things constant,
it allows us to maintain homeostasis. On the other hand, positive
feedback is also possible. This means that if a change occurs in some
variable, the response is to change that variable even more in the
same direction. This has a de-stabilizing effect, so it does not
result in homeostasis. Positive feedback is used in certain situations
where rapid change is desirable”

University of Colorado: Homeostasis and Negative Feedback

Thought Contagions and Pathological Dieting by Aaron Lynch 

“If the population is slightly heavier than it was 25 years ago, it
might well result mainly from three things. One is the proliferating
availability of rich and super-rich foods. Another factor is less
exercise. Finally, more pathological diet thought contagions spreading
in society can also lead average people to gain weight in the long
run, with the exception of people who progress to anorexic or bulimic

Halting Time Pressure by David S. Sobel, MD, MPH and Robert Ornstein,

“Trying to control time by strict scheduling is like trying to control
what we eat by strict dieting. We become so obsessed with it that it
becomes more—not less—important in our lives. If we relax our grip and
stop seeing time as an enemy to be beaten into submission, time
relaxes its grip on us.”
Kaiser Permanente - 2003

Qpet, thank you for your patience and I sincerely hope this
information is closer to what you are looking for.

Kindest Regards,
qpet-ga rated this answer:5 out of 5 stars and gave an additional tip of: $40.00
Thank you,
Very interesting stuff!

Subject: Re: Diets don't work, why?
From: bobbie7-ga on 31 Jan 2003 08:10 PST
Thank you for the five stars and generous tip. 
I also found this research interesting.

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