Does low carb lower testosterone levels? I have been on a VLC diet for about a week now and I feel amazing. I only eat one meal a day, around 8:00pm, and I have never felt this good in my life. By the way I am 21 years old (male). I am trying my best to boost my testosterone, but I read a few things that say low carb diets decrease testosterone... I hope not. It wouldn't make sense to me anyways because this is how our ancestors ate.
Depends on how you look at it. Decreasing the testosterone:cortisol ratio and upregulating pregnenolone-steal is of course going to have a negative impact. On the other hand, carb restriction tends to coincide with fiber restriction, which means less fiber binding with the hormones that have undergone biliary excretion. As such, there is a greater chance for those hormones to undergo enterohepatic recirculation back into the bloodstream. On top of that, the greater intake of (specifically saturated, but also monounsaturated) fat also increases the absorption of those fat-soluble hormones (cortisol, estradiol etc. included, as well as cholesterol).
All told, I'd say it's probably a wash since the presence of cortisol generally trumps the presence of testosterone, at least insofar as muscle anabolism is concerned. What would be ideal would be to not restrict carbs and to eat a lot of saturated fat, especially when you eat appreciable amounts of fiber.
I should also say that this all applies to the corresponding hormones in females as well.
Empirically, I've never experienced reduced testosterone symptoms (irritability, lethargy, low sex drive, depression) when eating low carb - in fact much the opposite.
Frankly though, it could have still be less than optimal as I am also still a fatty fatty fat fat, and the reduction of weight and increased mobility is having a more positive impact on my cortisol levels to counteract.
When going VLC, I also tend to go heavy on eggs, liver, and fish oil... and more recently quite a fair amount of coconut fat (brain energy... ACTIVATE!). I think having a decent intake of saturated fats, as well as high zinc and sulfur-producing foods such as beef and eggs, contributes somewhat to at least a better balance of the oft-maligned hormone.
if memory serves me correctly
VLC lowers insulin which increases Sex hormone-binding globulin (SHBG)
and free testosterone is total testosterone minus Sex hormone-binding globulin (SHBG). so as long as your insulin doesnt get too low, then your free t will be okay
The stuff I've seen has been assumptive and questionable to me for our purposes (a Penn State study is referred to most often). ie. You take a diet, keep fats steady and play around with protein levels. Higher protein = lower testosterone. Lower protein = higher testosterone. If fat is the same and protein is high, then carbs are low. If fat is the same and protein is low, then carbs are high. So it's not necessarily low carbs are bad for testosterone, it's high protein is bad.
Going to that Penn State study, they took 12 athletic people (probably college students) and watched their food for a month of the study. They were probably on the Standard American diet, and they weren't low carb long enough to ketoadapt. So the assumptions could be wrong for someone on a Paleo diet or low carb for a length of time, or anyone that's not a 23 year old athletic person that can bench press 176 pounds...
Which all boils down to, get your blood tested, then tested again after a while on low carb and compare. You think you need to boost your testosterone (but at 21 you shouldn't need to unless there's some other issue going on).