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Brown Adipose Tissue, CT, and Resting Metabolic Rate

Discussion in 'The Cave' started by KalosKaiAgathos, Apr 4, 2019.

  1. KalosKaiAgathos

    KalosKaiAgathos New Member

    Seems like two concepts which I've found extremely interesting in the last few years are related.

    Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5605155/

    " The available evidence indicates that, in adult humans, nonshivering thermogenesis is activated before shivering in response to mild cold, and can account for an increase of 10–20% in metabolic rate."

    Resting metabolic rate also declines big time in people who yo-yo diet, setting them up to longer-term fat gains.

    I wonder whether brown adipose tissue losses might explain that loss of resting metabolic rate. If that is the case, metabolism may be restored by using CT.

    Obese people generally have lower brown adipose tissue stores, and there's good evidence to assume that their better insulation is key to that process. If such people were to lose fat eating very little (under the standard faulty and shortsighted CICO model), they may not have the means to build up their brown adipose tissue stores again.

    Additionally, evidence suggests that circadian rhythm affects brown adipose tissue activity, as the study I'm citing states:

    "To make matters even more interesting, it has been recently discovered that nonshivering thermogenesis displays an ultradian rhythmicity that may be independent of sensory inputs."

    Hence, if you fuck up your circadian rhythm, brown adipose tissue no longer functions, making you prone for later fat gains. Most people have disrupted circadian rhythms, and may thus gain fat because their resting metabolic rate no longer functions the way it should...

    Just a hypothesis, need to do more research to confirm...
     
  2. Lahelada

    Lahelada New Member

  3. KalosKaiAgathos

    KalosKaiAgathos New Member

    Sure, I'm aware of beige :)

    Beige has somewhat of a different structure (fatty acid makeup, for example), but does get the properties of brown fat (UCP1 expression) with more cold exposure.
     
  4. kris90

    kris90 New Member

    Prolonged daily light exposure increases body fat mass through attenuation of brown adipose tissue activity
    https://www.pnas.org/content/112/21/6748

    Light at night alone lowers BAT activity. It makes sense, because leptin has a diurnal rhythm, and it rises in the evening (when its dark, and temperature goes down) at which point it reaches the leptin receptor between 12 and 2 AM.

    Leptin levels are also higher in summer when the light cycle is longer, there is less BAT activity and we are eating carbohydrates. People tend to live that environment year round due to chronic blue light exposure and this results in leptin resistance.
     
  5. KalosKaiAgathos

    KalosKaiAgathos New Member

    Great find! Very interesting, and the study can be read in many different ways IMO. Too bad there's very little info on what type of light was projected at the mice.

    I'd expect very different results for natural light versus blue light for 12 or 24 hours a day, for example, as IR light can independently lower the need for BAT in the first place (you'll need less BAT activity when you're standing in the sun while it's snowing, than when there are heavy clouds, all other variables being equal).

    On the other hand, because the intervention group received light for 24 hours a day, circadian mismatches are guaranteed and can reasonably be expected to be isolated in the intervention group.
     
    kris90 likes this.

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