Reducing Body Fat % Absent Caloric Deficit: Preliminary Thoughts
A recent conversation in a sourcing subreddit occurred in which it was suggested that AAS actively reduce fat absent of a caloric deficit, while SARMs do not. Of course, we all know of some compounds such as DNP, Clen and Cardarine, which will cause fat loss to occur, which are not AAS. Over the course of the discussion someone chimed in about Anavar (oxandrolone) directly reducing fat (again, absent a caloric deficit) which got me to doing some reading... how important is a caloric deficit for different compounds?
So first up, Testosterone most definitely improves body composition. I'm not going to spend much time on proving that out, but if you're interested in this as background reading check out this study. This is also established for Nandrolone and to less of an extent RAD-140 and MK2866.
My approach to cutting has always been diet based. When I was/am on PEDs, I would of course run something to help preserve muscle (often YK11 or Ostarine etc.) in addition to whatever dose of test I was choose/chose. My assumption is that the primary reason for using PEDs while cutting would be mostly for nitrogen retention benefit (to preserve muscle), and that the body composition benefits would be more or less negligible.
As it turns out, there is a significant impact to fat loss that can be attributed to PED use, depending on the compound being used.
Study 1: n=30 aged 40-60. After 3 months, both Anavar and Testosterone groups had lost 3% of body fat, with Anavar group losing a significant amount of visceral fat compared to placebo or the group taking Testosterone. This was also evidenced in subjects taking nandrolone decaoate (group subbed in nandrolone after elevated liver values on 'var risked the study). The group taking Test had a reduction in subq fat, but visceral fat increased slightly by 15cm2, while the group taking nandrolone had visceral fat substantially increase twice as much, to 30cm2.
Subq fat is found directly under skin, usually above muscle such as over top of your abs. Despite looking ugly, it's not as bad as you may think it to be. Visceral fat is fat that surrounds organs, and is almost wholly a bad thing.
Study 2: 344 rats. Testosterone reduced fat mass by 27%, while tren reduced fat by up to 51% (this fat loss was highly dose dependent), when compared to the group that had their testicles removed.
Study 3: n=120 elderly men using 3mg Ostarine. Fat mass fell by about 1.5%, while lean body mass increased by about 3%.
Study 4: n=18 men took 10mg/d Anavar for a week. After 7 days, baseline and post study hepatic ketogenesis was compared. It was established that 'var increases ketogenesis.
Nutrient Partitioning & Nitrogen Balance
So at this point in my research, I understood that fat loss is probably true of many/most AAS and PEDs with a high anabolic rating. But why? The most obvious reasons are nutrient partitioning and Nitrogen Balance.
Nutrient partitioning is the theory is that your body becomes more efficient in using the food it takes in. This is a big topic in itself filled with broscience and misunderstanding, but let's just take it for a given and we'll come back to this in a future write-up. Nitrogen balance has been covered a whole bunch already, but suffice to say that many PEDs improve nitrogen balance and it's a key part of building and maintaining muscle. More on this subject here. Nitrogen balance also supports improved protein synthesis.
This is all great for the gaining of muscle, but the gap in these three items is that it does not easily explain fat loss.
Testosterone promotes the commitment of pluripotent stem cells into the myogenic lineage and inhibits their differentiation into the adipogenic lineage. The hypothesis that the primary site of androgen action is the pluripotent stem cell provides a unifying explanation for the observed reciprocal effects of testosterone on muscle and fat mass.
Translated: stem cells turn into muscle cells instead of fat cells when subject is dosing Testosterone. Visual.
Presumably, as the body regenerates cells, this action will improve body composition over time. It would also be dose dependent - higher doses of Testosterone would result in a higher proportion of stem cells acting this way, and anecdotal evidence supports this view.
It's unclear if this would be true for non-testosterone based anabolic PEDs (specifically SARMs). I would lean toward that it's the activation of the androgen receptor that would trigger this given evidence of fat loss on RAD-140 and Ostarine, though the researchers hypothesize that it's specific only to Test. Ultimately they conclude it's an unknown.
Lipolysis / Ketogenesis
A old (1935) study done on castrated dogs shows that 'male hormone' (presumably testosterone) caused an increase in 'fat metabolism' (presumably lipolysis). The data is definitely hard to read, but the old-timey hand drawn graphs are cool. The break down of fatty acid they show is not completely unexpected. Study 4 shows the ketogenic effects that Anavar causes which also neatly helps explain the fat loss in Study 1, (though that specific Metho of Action may be limited to 'var and a few other compounds). This would be compound and dose dependent.
Assembling a complete list of compounds that have a proven impact on fat loss, and by how much, would be a worthwhile but enormously time consuming task... That said, I think it's fair to say that many/most commonly taken AAS and SARMs improve body composition through one or all of the actions above. SARMs are the least understood - it's entirely possible that the body composition benefits shown in Ostarine and RAD-140 trials are due to an as of yet unknown reason, though I lean toward what is outlined in the Stem Cell section.
I do wonder if their is an association between the anabolic rating and fat loss. Compounds that build comparatively more muscle would, under the Stem Cell theory outlined above, mean less cells are created as adipose tissue.