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  • Writer's pictureScott Murray

the truth about being shredded

As I said in the video, here are some of the main reasons according to the literature which I was going to ramble on about as to why I would naturally predict my testosterone levels to be low.


The first and most dominant example I touch on is being too lean which can be just as much of an issue as too fat where, as you can see in the graphs below by Rossow et al 2013 on the changes observed during a bodybuilding contest prep, one of the main hormones to take a hit when going from 14.8% to 4.5% body fat was testosterone. So in the table you can see that test drops all the way from 9.22 to 2.25 nanograms per millilitre during a prep thus equating to a 77% decrease but then in the recovery phase where they gained back to 14.6% bodyfat, test levels pretty much got fully restored. Therefore overall, there seems to be a sweet spot for test levels and bodyfat which I’m confident recommending to be anywhere between 8 at the lowest and 15%


The second factor has to do with my diet and my overall fat intake as I do adopt a relatively low fat diet and the research supports the fact that higher fat diets are more “optimal” for test levels. For example, in 2004, Sallinen et al conducted a study assessing the relationship between diet and anabolic hormone concentrations concluding that , out of the three main macronutrients both dietary fat & protein were significantly correlated with higher concentrations of both serum and testosterone and free testosterone however interestingly enough, excessive protein intakes seemed to cause test to decrease. Therefore, overall, fat seems to be the king for testosterone levels which is confirmed again in a study by Hämäläinen EK, 1984 where a decrease in fat from 40% to 25% of total energy intake resulted in modest, but significant, reductions in testosterone and free test levels.

Wang et al 2005 showed similar with a low fat diet resulting in a 12% decrease in test with Dorgan 1996 showing similar beneficial effect for fat that a 40% fat diet lead to a 13% higher test level than 18% fat


The next factor has to do with micronutrients, vitamin D in particular which I lack due to my hermit life and also living in Ireland. For those unaware, vitamin d is strongly linked to testosterone levels. For example, Wehr, 2010 showed that men with sufficient vitamin d levels to have significantly higher levels of testosterone than those deficient with another study by Pilz et al 2011 showing supplementation of up to 3,332 IU vitamin D per day for 1 year increased test levels by ~20%


Of course the next factor has to be my lack of sleep which is likely the main one alongside my level of bodyfat in that sleep is CRUCIAL for optimising hormone levels. For example, Goh & Tong (2010) showed that men who sleep less than 4hrs/day have ~60% less total testosterone and 55% less bioavailable testosterone than men who sleep >8hrs. Furthermore, as seen in the graph and the dotted line vs the thick line, another study by Leproult & Van Cauter 2011 also showed this where sleeping 5hours per night for 1 week resulted in a 10% to 15% decrease in daytime testosterone levels. This is yet again confirmed in one final super cool graph below seen by Penev 2007 who do literally show a linear relationship between the amount of sleep you get and both total and free testosterone concentrations thus proving that sleep is an independent predictor of test levels


Now, when it comes to training, I don’t do my test levels any favours either as I do tend to overtrain quite frequently which has been known to supress anabolic hormone levels. Correct, training is good but there does come a limit where too much ie overtraining can negatively impact testosterone and this is also dependent on the type of overload. Overall, overdoing intensity seems to be better than overdoing volume as per a paper by Fry et al 1998 who got participants to do 10 single 1RM squats every day for 2 weeks showing that although very high intensity, the it did not alter pre exercise concentrations of total testosterone and actually slightly increased the acute response. HOWEVER, when it comes to volume it’s a completely different story as, according to Schoenfeld 2010, studies seem to show that overtraining is more a result of excessive volume than intensity and this can be seen in the graph by Häkkinen 1989 where as you continually increase volume testosterone plummets


This then gets worse when you combine lifting with cardio (which I do) as seen in the graph by Taipale et al ‎2013 where, cardio done after weights lead to a significant reduction in testosterone both 24 and 48 hours post exercise compared to doing cardio before exercise


Speaking of stress and overtraining, that is the final thing that would influence my testosterone levels as ideally you want to keep low. This is because, stress in general can greatly reduce anabolic hormone levels. For example, as you can see in the graph by Brownlee 2005, with elevated levels of cortisol i.e. the primary stress hormone, as seen in the graph, there is almost a linear negative relationship with testosterone so meditating and just relaxing is also important

Thanks for reading this far if you have lol, the support really does mean the world and if you want any more info on the impacts of being shredded on metabolism, hormones etc, the following 2 are good resources, 1 being a highly reputable paper on metabolic adaptation to weight loss/being lean and another being my video series on testosterone and how to maximise it naturally.

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