Exercise may yield greater capacity to store fat under the skin

PerSpinasAdAstra

PerSpinasAdAstra

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Article:

"The fat tissue taken from the regular exercisers had a greater capacity to expand and store fat just underneath the skin."

“People might think, ‘I don’t want my fat cells to expand,’ but if they don’t expand, then that fat is going to go somewhere — and it’s going to go to bad places like the liver and the heart” and other organs, Horowitz says.

"This kind of fat is known as visceral fat, and having too much of it can raise the risk of serious health issues such as diabetes and heart disease. The changes seen in the exercisers’ fat tissue may protect them from accumulating this more dangerous kind of fat, says Ahn, who is now a postdoctoral researcher at the AdventHealth Translational Research Institute in Orlando, Florida."

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This study may indicate why a sedentary lifestyle is a risk factor for Type 2. It suggests that Roy Taylor's 'Personal Fat Threshold' might have an exercise component rather than being entirely due to genetics or similar. If regular exercise enables subcutaneous fat cells to grow larger then that might, in effect, raise the weight level a person can reach before excessive levels of fat would occur in the liver. That perhaps suggests that exercise may also be an important tool in maintaining stability over time - helping to prevent re-accumulation of liver fat and thereby hinder disease progression.
 
Very nice study. It would have been neat if they had also done some scans to collect visceral & muscle fat.

Looking at the group they used for the expanding-fat-cells piece (Table 2), Both sedentary and active folks had similar BMI (about 30 on average) but the active people had signifiantly lower body fat % (avg ~31% vs ~40%). But no data I can see on where the extra fat went.

The active folks also had significantly lower HOMA-IR (1.4 +/- 0.9 versus 2.5 +/ 1.5). I think the usual cut-offs are 2.9 for full-on insulin resistance and 1.9 for "elevated". So a bunch of the sedentary people were definitely insulin resistant and most were "elevated" (as were some of the active people).

At face value, therefore, insulin resistance appears to be associated here with higher body fat %. Would adding in more scanning data refine that to an association instead with visceral fat amount? I'd bet 20c the answer is "yes" (but who cares what I guess).

On another note, this data set seems to be a nice snapshot of a fairly young (mid 30's on avg) overweight group many of whom seem started on the path towards T2D. At the moment they look fine in terms of glycemia (avg 4.6 vs 4.7 mmol/l fasting glucose for active vs sedentary) but the insulin resistance will overtake that as time passes.
 
Eddy Edson said:
Very nice study. It would have been neat if they had also done some scans to collect visceral & muscle fat.

Looking at the group they used for the expanding-fat-cells piece (Table 2), Both sedentary and active folks had similar BMI (about 30 on average) but the active people had signifiantly lower body fat % (avg ~31% vs ~40%). But no data I can see on where the extra fat went.

The active folks also had significantly lower HOMA-IR (1.4 +/- 0.9 versus 2.5 +/ 1.5). I think the usual cut-offs are 2.9 for full-on insulin resistance and 1.9 for "elevated". So a bunch of the sedentary people were definitely insulin resistant and most were "elevated" (as were some of the active people).

At face value, therefore, insulin resistance appears to be associated here with higher body fat %. Would adding in more scanning data refine that to an association instead with visceral fat amount? I'd bet 20c the answer is "yes" (but who cares what I guess).

On another note, this data set seems to be a nice snapshot of a fairly young (mid 30's on avg) overweight group many of whom seem started on the path towards T2D. At the moment they look fine in terms of glycemia (avg 4.6 vs 4.7 mmol/l fasting glucose for active vs sedentary) but the insulin resistance will overtake that as time passes.
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I guess there's a simple point here: as far as I can see, the expanding-fat-cell thing is an interesting mechanistic hypothesis but the actual data here doesn't necessarily say much about it in terms of actual outcomes.

The active folks had better insulin sensitivity etc and a lower body fat percentage. The better insulin sensitivity may well have been due to lower visceral (and muscle) fat, but even so this would be consistent with a "personal fat threshold" which doesn't really change with amount of exercise.It could simply be that the active folk have less fat, and so less risk of crossing over their thresholds.

Or not ... but I think you'd need more actual outcome data to say one way or the other.
 
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Eddy Edson said:
I guess there's a simple point here: as far as I can see, the expanding-fat-cell thing is an interesting mechanistic hypothesis but the actual data here doesn't necessarily say much about it in terms of actual outcomes.

The active folks had better insulin sensitivity etc and a lower body fat percentage. The better insulin sensitivity may well have been due to lower visceral (and muscle) fat, but even so this would be consistent with a "personal fat threshold" which doesn't really change with amount of exercise.It could simply be that the active folk have less fat, and so less risk of crossing over their thresholds.

Or not ... but I think you'd need more actual outcome data to say one way or the other.
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Understood. I didn't read the actual study as I thought it was paywalled. If it available for free somewhere or do you have access past the paywall?

BMI doesn't strike me as a good way to compare like-for-like as you rightly point out. Body fat percentage and the results of something like a DeXA scan would be a much better measure perhaps - i.e. does exercise actually lead to more fat being stored subcutaneously and thus result in lower levels of visceral fat? If they're comparing people with equivalent BMI but greatly varying levels of muscle mass/body fat percentage then the conclusions aren't at all as solid the text of the article suggests. A study comparing people of equivalent body fat percentage to see whether exercise influences tendency toward subcutaneous storage might be lot better as regards any conclusions that might be drawn about the 'personal fat threshold' issue.

I've wondered why exactly low skeletal muscle mass is a known risk factor for NAFLD. If NAFLD risk and Type 2 risk are effectively the same thing, how does muscle mass come into it? I thought maybe that study suggested part of the answer - perhaps the 'personal fat threshold' isn't a fixed thing but something that can change over time, which might be part of the reason why people are more likely to become diabetic as they get older - putting on weight very probably but perhaps also losing muscle mass and being less active.
 
PerSpinasAdAstra said:
Understood. I didn't read the actual study as I thought it was paywalled. If it available for free somewhere or do you have access past the paywall?

BMI doesn't strike me as a good way to compare like-for-like as you rightly point out. Body fat percentage and the results of something like a DeXA scan would be a much better measure perhaps - i.e. does exercise actually lead to more fat being stored subcutaneously and thus result in lower levels of visceral fat? If they're comparing people with equivalent BMI but greatly varying levels of muscle mass/body fat percentage then the conclusions aren't at all as solid the text of the article suggests. A study comparing people of equivalent body fat percentage to see whether exercise influences tendency toward subcutaneous storage might be lot better as regards any conclusions that might be drawn about the 'personal fat threshold' issue.

I've wondered why exactly low skeletal muscle mass is a known risk factor for NAFLD. If NAFLD risk and Type 2 risk are effectively the same thing, how does muscle mass come into it? I thought maybe that study suggested part of the answer - perhaps the 'personal fat threshold' isn't a fixed thing but something that can change over time, which might be part of the reason why people are more likely to become diabetic as they get older - putting on weight very probably but perhaps also losing muscle mass and being less active.
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Nature has the paper as free to read (not download) - just follow the link in the piece you posted. Lots of biochem - I can't wade into it very far so maybe answers to my points are in it somewhere.
 
Eddy Edson said:
Nature has the paper as free to read (not download) - just follow the link in the piece you posted. Lots of biochem - I can't wade into it very far so maybe answers to my points are in it somewhere.
Click to expand...
This link or another one? - https://www.nature.com/articles/s42255-024-01103-x

Via that link I can just see the Abstract text followed by this:
Nature Paywall.png
I can see some supplemental information but not the full text. Do I have to create an account to see it for free maybe? Or could it be free in some regions and not others?
 
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