1. RESEARCH UPDATE: The Weight Loss Plateau
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"The untold story about leptin and weight loss..."

Have you ever found yourself stuck at a certain weight? And no
matter how hard you try, you can't seem to shift those last 10
pounds of fat?

Your body has a set point — a level of fat that it wants to
maintain. When you try to reduce your body fat below this set
point, your body fights back by reducing the number of calories
your body burns each day (your metabolic rate) and turning on the
appetite "switch" in your brain. The result is that weight loss
slows down and you get very hungry!

One of the hormones responsible for the increase in hunger is
known as leptin. Leptin (the Greek term for thin) is a hormone
released by your fat cells. When you lose fat, leptin levels
drop. When you gain weight, leptin levels rise.

When most people hear the word "hormone", they think of the sex
hormones, such as testosterone or estrogen. Yet testosterone and
estrogen are just two of many hormones that regulate virtually
everything your body does.

Your body has billions of tiny fat cells. These fat cells respond
to hormones in one of two ways, depending on whether the signal
is lipogenic or lipolytic. The term lipo means "fat", lytic means
"breakdown", while genesis means "creation".

A lipolytic (pronounced lip-o-lit-ik) hormone increases the
number of fat calories burned for energy. This leads to a
reduction in the size of your fat cells. Hormones that promote
fat storage, on the other hand, are known as lipogenic
(pronounced lie-po-jen-ik). Lipogenic hormones increase the size
of your fat cells.

The thyroid hormones are among the most important lipolytic
hormones. However, one of the hormones in the thyroid family —
known as triiodothyronine (pronounced try-o-die-thigh-ron-een) —
can drop when you lose just 10% of your bodyweight.

Contrary to popular belief, triiodothyronine (also known as T3)
levels also drop when you include exercise as part of your weight
loss program. They don't, however, drop to the same extent in
everyone. Researchers from the University of North Carolina, for
example, report that free T3 levels either drop or show no change
in response to the same exercise program.

The results reveal two distinct categories of responses —
responders and non-responders. In the responders, T3 levels
dropped by almost 30% after ten weeks. The non-responders, on the
other hand, displayed no significant hormone changes. More
interesting still, recent studies suggest that the same "master"
hormone that controls the production of T3 is also linked to
leptin levels.

Before the discovery of leptin, body fat was seen as a lifeless
source of energy. However, exciting work by researchers at the
Rockefeller University in the 1990's led to a radical change in
perspective.

Some mice have a genetic defect that predisposes them to gain
weight. When the mice were injected with leptin — the hormone
this "broken" gene normally produces — the mice lost weight.

Further animal research shows that leptin can prevent weight loss
slowing down. Obese rats were given a mixture of the
weight-loss drug sibutramine (known commercially as Meridia) and
leptin, to see if the two substances together might help the
overweight animals lose weight.

The rats taking sibutramine alone lost more weight than rats
given either leptin or saline. However, the rats given a mixture
of sibutramine and leptin shed significantly more weight than the
group given sibutramine alone.

One of the ways in which leptin regulates weight is to increase
your appetite as your body fat levels drop. Some direct evidence
linking leptin and hunger in humans comes from a trial carried in
the American Journal of Clinical Nutrition.

Twelve overweight but otherwise healthy women followed a
low-calorie diet for three months. The researchers found that the
desire to eat doubled in response to the diet. More interesting
still, the volunteers reporting the greatest increase in hunger
were those with the largest drop in leptin.

Once leptin has been secreted by your fat cells, it travels to
the hypothalamus. This is the part of your brain that controls
eating behavior. In the medial hypothalamus, leptin activates
anorectic nerve cells, which suppress your appetite. At the same
time, leptin prevents orexigenic cells from stimulating your
appetite.

Although it might seem counterintuitive, many obese individuals
actually have high levels of leptin. On the face of it, this
appears to blow all of the theories regarding leptin and weight
loss out of the water. After all, if people who are obese have
high levels of leptin, surely they wouldn't be obese in the first
place.

While obese people do have high levels of leptin circulating in
their body, that doesn't mean the leptin is active where it needs
to be — the hypothalamus. Instead, they seem to have developed a
form of leptin resistance, where leptin is unable to make the
"jump" from the blood to the brain.

--- The bottom line ---

As you get closer to your target weight, your rate of weight loss
will slow down. It's normal, and it happens to almost everyone.
However, the degree to which it happens will vary from person to
person. No study has shown that if you deprive people of the same
number of calories, they will all lose the same amount of weight.

The effect of leptin on hunger and weight loss is still
controversial. There is evidence to show that daily leptin
injections help some people to lose weight faster, while a
low-dose course of "replacement" leptin may reverse some of the
metabolic changes that occur during weight loss. As with many
drugs, the long-term effects are not well understood, and
there are still more questions about leptin than there are
answers.

For many people, losing fat and keeping it off is difficult. Yet,
there are no quick fixes or easy solutions. The concept of reward
without work simply does not exist anywhere in Nature. A farmer,
for example, must work hard — preparing the ground and planting
the seed — before expecting to get a great harvest.

Don't be deceived by the false promises of "negative calorie
diets" that claim to help you lose up to 14 pounds of weight in
seven days. Almost anything difficult, any challenge, takes
patience, time and a desire to work for it with all your heart.

To view this update on-line, visit:

http://thefactsaboutfitness.com/research/leptin.htm

I do have a question though. So is this article saying we get more hungry as we lose weight? Is this a normal or abnormal reaction?
Also if you have alot to lose, is resistence a normal thing and does it every go away?

As leptin gets lower your appetite increases, your metabolism slows down, and your body burns more muscle. Your body works against losing weight believing you are starving. In a modern traditional, low-calorie, hi-carb diet, leptin levels drop right away causing a stop in weight loss and tremendous food cravings.

It is not clear to me what low-carbing does. Leptin must go down but the food cravings must have something to do with carbs. Eating more protein likely helps save your muscles. There is a good chance it has something to do with plateaus.

The article failed to say that leptin can be regenerated by eating carbs, commonly known as a refeed. A day of Coke and fruit loops will raise you leptin levels nicely, and add a couple pounds. The thinner you get the more you need leptin (and refeeds) in order to loose weight.

Body builders seem to know about Leptin.
http://www.theministryoffitness.com...s/article18.htm

I have believed in the leptin concept for a while, having learned about here. I am now getting thin enough that I refeed every week. I have managed maintain a .5 to 1 pound weight loss every week since starting refeeds.

I consider refeeds a weight loss tool to accompany this amazing low-carb diet. When I get to my target weight, I hope that it will be the end of refeeding, and then onto low-carb maintenance.

While it may work for some, I question recommending a "refeed" as a general policy. For one, those carbs can trigger a totally falling off the wagon for the addicted. I have been low carbing for 9+ months and have had 2 plateaus after the induction one. The weight loss always starts up again and i don't have any different hunger pattern that I did when I started. I have also read a number of stories of people who did strict Atkins and lost 100+ without going off plan.
I found the article interesting and informative, but Ithink that the evidence shows that low carb is a bit different. The leptin seems to be regenerated during plateaus even if you stay with low carb. Nyah Levi