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Years to turn over fat, belly fat biopsy, liposuction fat color
"Based on measurements of the incorporation of linoleic acid into adipose tissue and assuming that other fatty acids exhibit similar kinetic characteristics, the half-life (T1/2) of adipose tissue fatty acids is approximately 600 days (1, 6), the fractional turnover rate (which equals ln(2/(T1/2)) being 0.12% per day. The total body fat of men would thus completely be replaced in 800 to 900 days. Indeed Turpeinen (8) reported that a change in dietary fat is optimally reflected in the fatty acid composition of subcutaneous adipose tissue only after a period of at least 3 years.
A Mathematical Relationship Between the Fatty Acid Composition of the Diet and That of the Adipose Tissue in Man https://pubmed.ncbi.nlm.nih.gov/7355785/
"During thirty-eight fat-free days the patient's caloric expenditure was of the same order of magnitude as the total caloric value of his entire adipose depot, yet body weight did not change nor was adipose composition altered . Clearly, there must have been intense lipogenesis from carbohydrate; but, the lack of accumulation of 16:0 and 16:1 and lack of decrease in 18:2 strongly argues against the participation of the entire adipose depot in the new synthesis of fatty acids."
"If one considers the rate at which dietary fat exchanges with adipose fat... the exceedingly slow nature of this process is evident... [the half-life] is therefore between 750 and 350 days. However, numerous isotype studies have demonstrated that the turnover of depot fatty acids is far more rapid than these calculations indicate... One reconciliation of these contradictory approaches to the problem of depot fatty acid turnover is to postulate the existence of at least two separate metabolic compartments in adipose fat."
Studies of Adipose Tissues in Man https://sci-hub.tw/10.1093/ajcn/8.4.499
I like the "two separate metabolic compartments" idea because it seems consistent with the observation that belly fat seems to be added first and removed last, when compared to other body fat. The studies at
https://www.functionalps.com/blog/2013/11/19/thigh-and-buttock-fat-depots-more-unsaturated-than-abdominal-fat-depots/ support the idea of there being a difference.
Those studies analyzed fat from biopsies or from liposuction. It makes me wonder: If liver biopsy is too invasive to collect, maybe patients could get fat biopsies instead. A fat biopsy might cost about $100 to a physician to collect in 2012, according to https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3638025/ . I assume this would total to at least several hundred dollars from the patient. As painful as that and the big needle stick sound, a patient might prefer to confirm they actually have a carotenoid problem before diving into the extreme diet / skin product / supplement / lifestyle changes and the initial detox symptoms.
"Of all the adipose tissue sites evaluated, the abdomen showed the strongest correlation with long-term dietary carotenoid intakes and with serum (indicator of short-term intake) for most carotenoids."
Site-specific concentrations of carotenoids in adipose tissue: relations with dietary and serum carotenoid concentrations in healthy adults https://academic.oup.com/ajcn/article/90/3/533/4597027
"Whenever I have a patient who seems to have very white or very orange colored fat, I always ask them about their diet. Patients with orange colored fat will almost unanimously say they love eating vegetables, including green leafy vegetables. " Mats Hagstrom, M.D. https://www.realself.com/question/new-virginia-ia-gross-question-fat-fat-yellow
At least some liposuction fat does look very orange: (Warning, very gross looking)
- "What does a liposuction look like?" https://www.youtube.com/watch?v=a0Nv2pP82dI
- "Liposuction Demonstration Beleza Medspa Austin TX" https://www.youtube.com/watch?v=kZcuODfnD9M
- "Vaser vs MPX Laser" https://www.youtube.com/watch?v=uhknxlLUSLE
I wonder what I had/have stored on thighs. When I rolled my skin(with fat under it) I felt a lot of little bumps+ I had/have a lot of acne(white heads) in that area.. Now those bumps reduced a lot. I wonder if it was Vit A.. Anyway I had those bumps only on my legs. So I think the fat composition can be different from place to place. In some places is better blood flow, some places are cold some are hot all the time etc...
@dan, great post! Interesting points and some great outside -the-box ideas.
I need to keep re-reading it, it's jam-packed. Let's see:
It can take up to 3 years for your body to "re-visit" all your old fat stores. Belly fat may be the slowest to change over, and it is different than other fat (for instance, abdominal is more saturated?) We should think about testing our fat rather than our liver for VA overload. Liposuction sometimes resutlts in orange fat, sometimes in white and sometimes in brown colored fat stores being removed. People who eat lots of colored vegetables have oranger fat. Carotenoids might be more likely to be stored in the abdomen than in other fat.
What else is in there? Lots to unpack!
Regarding belly fat being "different" I've been thinking about how (it is a known thing that) pig fat has a different makeup when taken from different areas of the body. The leaf lard (around the kidneys) is known for being more solid/flaky at room temp, more tasteless in baking. Other pork fat is meatier tasting. Some people believe leaf lard gives a buttery flavor to cooked items. (which could be a scary thought...)
Such interesting ideas and observations, @dan, thank you! 😁
Love that quote from the doctor Hagstorm. Good find!
The belly fat idea aligns with my experience—even though I have lost a significant amount of weight “all over” my waist-to-hip ratio has not changed a whole lot at this point, and I am still definitely eliminating carotenoids (maybe there is a store of them in my belly fat 😆).