(no subject)

[ljgeoff]

I'm taking a class in Nutrition class called Obesity and Weight Management. My professor has been a proponent of HAES (Healthy At Any Size) for decades (in fact, he says that as far as he knows, he started talking about this concept earlier than anyone else he knows). We're doing a section on adipokines that is fascinating.

First you should know that there are three kinds of body fat. There is the fat that most people think of as fat, which is called "white fat"; this is an adipose cell that is mostly composed of a large drop of fat with the cellular organelles and nucleus scrunched over in a little huddle along the cell wall. This fat is primarily subcutaneous (directly under the skin) fat. Another kind of fat cell is called "brown fat". Instead of one big droplet of fat in this type of cell, there are several smaller droplets, and the cell has a large number of mitochondria. Mitochondria are the cellular organelles that convert cellular food into energy. Brown fat cells are made to easily convert their stored fat into energy, where white fat cells are storage cells. One interesting thing about white fat and brown fat is that an organism will begin to turn their white fat into brown fat if they increase their muscular activity. Both white fat and brown fat are the fat right under your skin. This type of fat has very little primary effect on a person's health. Secondary problems might include things like joint issues, sleep apnea, and various social/psych issues.

What I find most fascinating about fat is the way visceral fat works. Visceral fat is the dangerous fat. It causes primary health problems, such as high blood pressure, insulin resistance and lipogenisis (making more fat cells).

Visceral fat works as an endocrine gland, secreting several types of hormones and steroids that do some really interesting things. Here's a few:

Leptin: this protein is secreted by visceral fat to give the brain an idea of the fat mass of the body. Scientists are not too sure how this works - there are two probable processes: either the brain notices the total amount of leptin in the system, and watches it go up or down, or it develops a "set point", and notices variations from the set point. Since the set point process is used for other brain monitoring functions, I have a hunch that this is the way that leptin is observed by the brain. As visceral fat increases, the brain gets a lot of leptin, and may become resistant or in some way become less sensitive to the leptin.

Now, when the brain perceives that leptin is decreasing, and this may occur from resistance, the brain activates two very powerful appetite stimulants - Neuropeptide Y (NPY) and Agouti-Related Peptide (AgRP).

When the brain perceives a lot of leptin, it sends out the signal to produce Alpha-Melanicortin Stimulation Hormone (a-MSH). This hormone functions to both stimulate the system to burn fat and represses fat storage.

Adiponectine is another protein hormone that is secreted by fat cells. This protein is interesting because, as visceral fat increases, production of adiponectine decreases. This is very unfortunate in that adiponectine modulates a number of metabolic processes, including glucose regulation and burning fat. It also promotes insulin sensitivity and has anti-inflammatory effects.

Resistin production, on the other hand, is produced increasingly by visceral fat as visceral fat increases. Resistin causes insulin resistance, simple as that. This is bright, shiny new research. We don't know how resistin works yet, I think, but it doesn't seem to be an insulin analogue.

Interlukin-6 is the factor that the body uses to form a needed inflammation. This one can be good when it works, and really bad when it doesn't. When it works, interlukin-6 helps the body fight off sickness and such. During strenuous muscle activity (and only during strenuous muscle activity), it causes the body to burn a lot of fat and it inhibits insulin resistance.

But, when it doesn't work, Interlukin-6 can cause general inflammation to the cardiovascular system. This one of the causes of obesity-related high blood pressure. The increased mechanical resistance in the blood vessels is what is causing the high blood pressure.

Another protein secreted by visceral fat that has direct effect on blood pressure is called Endothelin. This protein hormone decreases the production of nitric oxide. Nitric oxide works to keep your blood vessels elastic, which the body needs when it dilates and restricts the blood vessels.

Not enough nitric oxide means that the blood vessels can't dilate, which increases mechanical resistance. In addition to relaxing and dilating blood vessels, nitric oxide functions to prevent heart disease and strokes in several other ways. It helps prevents atherosclerosis by preventing platelets and white blood cells from sticking to the vessel wall. Nitric oxide also, under many conditions, reduces the production of free radicals, which can cause your vessels to age rapidly. Further, it suppresses abnormal growth of vascular muscle cells which causes thickening of the vessels.

What is so very interesting and heartbreaking about this research is that it is showing us that the human body was not engineered for plenty; it was engineered to survive famine. When it gets beyond a certain mass, our visceral fat becomes "broken", and works diligently to keep us fat. It reminds me of those Japanese soldiers out on islands who never knew the war was over.

So, visceral fat is the only part of "being fat" that can kill you. A person's body weight is not a good measure of a person's visceral fat. Sumo wrestlers have a lot of subcutaneous fat, but an astonishingly small amount of visceral fat. But the skinny little nerd in the next cubical may have several liters of visceral fat. The primary indicator of visceral fat is a person's activity level.

How do you get rid of visceral fat? For gods sake, don't go on a diet. Dieting, especially yo-yo type dieting, increases visceral fat. The only way to get rid of visceral fat is to exercise.

And, I gotta tell ya, I hate to exercise. *sigh*

Comments

[elissaann.livejournal.com]

I hate to exercise, too, because I find it boring. But I have a high activity level, because my favorite methods of transportation are walking and bicycling.

[ljgeoff.livejournal.com]

I would guess from my increasing blood pressure and wonky sugar issues that I've got a goodly amount of visceral fat. I think that moderate exercise will keep one from growing visceral fat, but once you have it, you have to exercise a lot to get reduce it. One study said that to shrink visceral fat, a person would have to exercise to the equivelent of running 17 miles a week.

The only way to really monitor visceral fat at this time is with an MRI.

[elissaann.livejournal.com]

Does walking the same distance have the same affect? These knees don't like running any more, but I walk 5 to 10 miles in a normal day, just getting around Manhattan. Lots of stairs, too, because they're part of the landscape.

[ljgeoff.livejournal.com]

Now, I did some looking around on-line, and this is from the Mayo Clinic page:

"Since visceral fat is buried deep in your abdomen, it may seem like a difficult target for spot reduction. As it turns out, visceral fat responds well to a regular exercise routine and a healthy diet. Targeted tummy exercises can help to firm the abdominal muscles and flatten the belly.

Exercise. Daily, moderate-intensity exercise is the best way to lose belly fat — when you lose weight and tone your muscles, your belly fat begins shrinking, too. In fact, you may notice that your tummy bulge is the first area to shrink when you start exercising. The amount and type of exercise you should get varies depending on your current activity level and your health goals. Talk to your doctor about the right exercise program to promote good health and specifically combat abdominal fat.

Strength training. Some research has shown that exercising with weights is effective in trimming tummy fat. Talk to your doctor about how to incorporate strength training in your exercise routine.

[limnrix.livejournal.com]

I was considering today that pretty much the main determiners of healthiness are activity and nutrition. Simply living and working somewhere where I have to walk at least a mile a day makes me feel so much better. The entire American lifestyle tends to ruin this, because people will take their car only a few blocks sometimes. It's better to integrate it into the day and make it necessary, otherwise it feels like time deliberately devoted to putting yourself through pain.