Lose your fat cells? No way!
By Dov Michaeli MD, Ph.D
Ever wondered if loss of weight causes a reduction in the number of your fat cells? Wouldn’t it be wonderful if that was true? You go on a diet, you lose weight and a bunch of cells, and you’d never gain weight again. Except it ain’t true, as anybody who went on a diet knows; unless you stick with your diet forever you will gain back the weight you had lost. Why is that?
Your fat cell allowance
In theory,there are two ways you can increase your body fat: you can increase the number of fat cells in the body, and you can store more fat in each cell. The second way, increase of the fat content per cell, has been amply documented; the reason we have so much evidence for that mode of weight gain is that it is quite easy to document. All that needs to be done is take biopsies of adipose tissue before the and during the weight gain and measure the fat content. And if you want to really nail it: take an additional biopsy after a weight loss diet, and document the drop in lipid content.
But what about the number of fat cells? That’s much tougher to measure, for obvious reasons: you can’t do a total body fat cell count. Or can you?
In animal studies, this question can be addressed by labelling DNA nucleotides with radioactive isotopes such as 14C. Differentiated fat cells do not divide, and so radioisotopes, incorporated in their DNA in the last round of division before differentiation, remain there throughout the cells' life. The time of radiolabel incorporation, is therefore the 'birth date' of these cells. But the potential toxicity of radioisotopes means that such studies cannot be performed in humans.
Kirsty Spalding and her colleagues at the Karolinska Institute in Stockholm cleverly thought of the next-best option. Atmospheric levels of 14C have remained relatively constant for centuries, with the only major increase occurring between 1955 and 1963, when nuclear bombs were being tested above ground. A chain of reactions ensures that, at any given time, the radioisotope content of human DNA matches that of the atmosphere. The authors could thus follow fat-cell dynamics in individuals born around 1955–63.
Spalding et al studied the dynamics of fat-cell number in some 700 adults, both lean and obese, and combined their data with previous observations in children and adolescents.
As the results show, fat cells have a high turnover: new cells are continually being born to replace their dead predecessors. The average age of a fat cell seems to be about 10 years in both lean and obese individuals, and the number of fat cells as a proportion of all cells remains constant in each weight group. But the total number of new fat cells was higher in obese subjects, suggesting that they are replenishing an existing larger pool.
What’s the take home lesson for lean people? and for obese people?
Do the lean among us need to worry about our diet if we have fewer fat cells? Yes, we do: our fewer fat cells can still store large amounts of fat. Also, can obese people do anything about their weight? After all, they've already accumulated a large pool of fat cells in childhood and adolescence? Again, the answer is yes. Again, the answer is yes. They can still reduce the volume, if not the number, of their fat cells. But there is another tantalizing message here: researchers should uncover the mechanisms underlying fat-cell turnover. If they do, one could conceivably slow down the replenishment of fat cells that came to the end of their ten-year life span. End result: progressively lower fat cell mass. This is still not a panacea; as we know from studies of people who had undergone liposuction--they slowly regain their previous weight by storing more fat in the remainig cells.
Liposuction: it's futile, lady.
Oh well, pass the fois gras!
The Doctor Weighs In
in Adipogenesis, Dieting, Dov Michaeli, fat cells;adipocytes
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Obesity has been defined as when excess body fat accumulates in one to where their physical overgrowth makes the person unhealthy to varying degrees. Obesity is different than being overweight, as others determine obesity to be of a more serious concern.
As measured by one’s body mass index (BMI), one’s BMI of 25 to 30 kg/m is considered overweight. If their BMI is 30 to 35 kg/m, they are class I obese, 35 to 40 BMI would be class II obese, and any BMI above 40 is class III obesity.
Presently, with obesity affecting children progressively more, the issue of obesity has become a serious public health concern.
Approximately half of all children under the age of 12 are either obese are overweight. About twenty percent of children ages 2 to 5 years old are either obese are overweight. The consequences of these stats on our children are very concerning, considering the health issues they may or likely experience as they get older.
Worldwide, nearly one and a half billion people are either obese or overweight. In the United States, about one third of adults are either obese or overweight.
Women of low socioeconomic status are likely to be twice as obese compared with those who are not at this status. It is now predicted that, for the first time in about 150 years, our life expectancy is suppose to decline because primarily of this obesity problem.
Morbid obesity is defined as one who has a body mass index of 30 kg/m or greater, and this surgery, along with the three other types of surgery for morbid obesity, should be considered a last resort after all other methods to reduce the patient’s weight have chronically failed. Morbid obesity greatly affects the health of the patient in a very negative way. It has about 10 co-morbidities that can develop if the situation is not corrected. Some if not most of these co-morbidities are life-threatening.
One solution beneficial in many cases of morbid obesity if one’s obesity is not eventually controlled or corrected is what is known as gastric bypass surgery. This is a type of bariatric surgery that essentially reduces the volume of the human stomach in order to correct and treat morbid obesity by surgical re-construction of the stomach and small intestine.
Patients for such surgeries are those with a BMI of greater than 40, or a BMI greater than 35 if the patient has co-morbidities aside from obesity. This surgery should be considered for the severely obese when other treatment options have failed. The standard of care illustrating as to whether this surgery is reasonable and necessary should be clarified.
There are three surgical variations of gastric bypass surgery, and one is chosen by the surgeon based on their experience and success from the variation they will utilize. Generally, these surgeries are procedures related to gastric restrictive operations or mal-absorptive operations.
Over 200,000 gastric bypass surgeries are performed each year, and this surgery being performed continues to progress as a suitable option for the morbidly obese. There is evidence that this surgery is particularly beneficial for those obese patients that have non-insulin dependent Diabetes Mellitus as well.
It is believed that the results of this surgery to correct morbid obesity greatly limits or prevents such co-morbidities associated with those who are obese. Yet about two percent of those who undergo this surgery die as a result from about a half a dozen complications that could occur. However, the surgery reduces the overall mortality of the patient by 40 percent or so, yet this percentage is debatable due to conflicting clinical studies at times.
Age of the patient should be taken into consideration, as to whether or not the risks of this surgery outweigh any potential benefits for the patient who may have existing co-morbidities that have already caused physiological damage to the patient. Also what should be determined by the surgeon is the amount of safety, effectiveness, and rationale for a particular patient regarding those patients who are elderly, for example.
Many feel bariatric surgery such as this should be considered as a last resort when exercise and diet have failed for a great length of time.
If a person or a doctor is considering this type of surgery, there is a website dedicated to bariatric surgery, which is: www.asmbs.org,
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