Does the Keto Diet Lower Testosterone?

Does the Keto Diet Lower Testosterone?

Fat is essential for proper hormone production.

That statement is a fact. Fat helps regulate the production of hormones in the body, including testosterone. The necessary level of fat can be debated, but the American Heart Association recommends 20-35% of daily calories come from fat.

Thus, for a 2,000 calorie a day diet, that is 400-700 calories or 44-78 grams of fat per day. This is what the body will require to produce optimal levels of hormones and also to function properly.

Related - 30 Ways To Boost Your Testosterone Naturally

Since fat is linked to adequate testosterone, one would think that a ketogenic diet or another higher fat diet would lead to even higher levels of testosterone and advocates for these diets have even promoted that. Or, at the very least, it wouldn't have any negative effect on hormone levels, right?


Your keto diet might be turning you into a woman! Well, maybe not that extreme, but it appears that it might be possible to have too much of a good thing. Can low carb, or ketogenic diets lower your testosterone?

Based on available data, it absolutely can!

Firstly, glucose is responsible and plays a huge role in GnRH levels which lead to hormonal actions in the body. GnHR is a releasing hormone responsible for the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary.

These are all critical to the production of testosterone and other hormones. This can be one reason why these studies I am about to mention turned out the way they did. [1]

When carbs were reduced to 30% of one's diet, even more, carbs than most ketogenic diets recommend, testosterone and the ratio of testosterone to cortisol was reduced significantly in subjects. This wasn't just in normal people - this was also replicated in Olympic athletes. [2]

Cortisol levels skyrocketed as the athletes depleted glycogen and increased the cortisol to testosterone ratio in these highly-trained athletes. The effect was blunted and reversed with the inclusion of a carb-containing shake.

This is even more evidence than when I recommend a shake with MTS Nutrition Machine Whey and Machine Carb 10 IMMEDIATELY post workout, regardless of diet, you are doing great things for more than fat loss, but for recovery and hormone response to training. [3]

I recommend a balanced diet, as found in the Drop Factor Book, so don't think we are advocating super-high carbohydrate diets, but the evidence to include carbs in your diet is hard to ignore. In one study, high carb diets increased testosterone by 36% over low carb diets. [4] The carb group also had lower levels of the stress hormone, cortisol.

But I was told that carbs make you fat?

Contrary to what the people trying to sell you stuff or sell books or simply have befriended Oprah, diet is pretty simple and regardless of what your diet beliefs are, there is one thing we all agree upon:

Exercise is Awesome

Diet is very important, but to ward off a lot of lifestyle diseases like type-2 diabetes and obesity, a consistent exercise plan should be a part of your life. We have a TON of options available at TigerFitness, but the training found in the Drop Factor Book is a great option!

Back to Diet

The main variable to losing fat and gaining muscle is a caloric balance. Take in more calories than you burn and you will gain weight. Take in less than you burn and you will lose weight. Some simple dietary rules of thumb:
  1. Set protein to 1-1.5 grams per pound of body weight daily.
  2. Set Fat to 0.3-0.5 grams per pound of body weight daily.
  3. Fill in the rest of your caloric needs with carbs.
  4. Find your TDEE, or Total Daily Energy Expenditure HERE (How many calories you need per day).
  5. Find the macronutrient breakdown you want and calculate macros based on your TDEE here.
  6. As stick point are hit if losing fat, drop carbs by ~40-60 grams per day (based on weekly progress to lose 1-2 lbs a week) or increase activity (cardio).
  7. As stick points are hit if trying to gain mass, increase carbs by ~40-60 grams per day (based on weekly progress to gain .5-1lb a week) or just check out Mass Diet.

The Take Home

I wouldn't worry about keto lowering your testosterone one bit. If you enjoy the diet, DO IT!

Sticking to it will be much better than a free-for-all of fat gain. But the message here is that there is no perfect diet. Do what works for you and please check out all of the resources in this article to help you find the perfect diet.

Please comment down below what works best for YOU so that your experiences can help out fellow readers!
1) Roland, AV et al. Regulation of gonadotropin-releasing hormone neurons by glucose. Trends Endocrinol Metab. 2011; 22(11): 443-9
2) Lane, AR et al. Influence of dietary carbohydrate intake on the free testosterone: cortisol ratio responses to short-term intensive exercise training. Eur J Appl Physiol. 2010; 108(6): 1125-31
3) Gleeson, M et al. Modification of immune responses to exercise by carbohydrate, glutamine, and anti-oxidant supplements. Immunology and Cell Biology (2000) 78, 554561
4) Anderson, KE et al. Diet-hormone interactions: protein/carbohydrate ratio alters reciprocally the plasma levels of testosterone and cortisol and their respective binding globulins in man. Life Sci. 1987; 40(18): 1761-8
Previous article The Drop Factor Book by Marc Lobliner


Nadi - September 25, 2019

I can’t tell if this article was supposed to be miss leading, or if you just didn’t read the studies you’ve cited as your sources.

Study 1 which i believe is this one: deals with the effects of glucose on GRNH releasing Neurons and literally has nothing to do with low carbohydrate diets, never mind ketosis.

Study 2, this one: deals with the short term effects of carbohydrate reduction on the free testosterone to cortisol ratio’s

First – (As the study pretty clearly states) This would be an indication of over training, and the body’s stress response. An increased stress response is hardly surprising given that it is believed to take around a week or more to adapt to ketosis, and this study took place over 3 days. I’ve been on low carb (not ketosis) for a while and i can tell you the first few days? absolutely sucked.

second- The participants where on a low carb diet, which is not quite the same as a ketogenic diet. I feel like it might be important that the study you are using to support your article on the effects of ketosis is, at the very least, an actual study on Ketosis.

Study 3 – possibly this one: looks at the increased risk of transfer of pathogens (its a fancy word for germs marc i got you) on the immune system in athletes following heavy training, it does mention that this can be compounded by poor nutrition using reduced carbohydrates/protein and micro-nutrients as an examples.It literally does not mention testosterone, ketosis or the ketogenic diet, furthermore I’m not sure the training endured by competitive athletes would be applicable to your audience who i imagine are largely interested in ketosis for fat loss and aesthetics. “Olympians were also affected” was an interesting spin considering the study was specifically of athletes (also meaning in addition to who?). It also mentions that there is little evidence that supplements will alleviate this effect, which is probably not something you should advertise here; you literally sell them marc. In your actual store. Did anyone proof read this? Anyway moving on!

Study 4 – was a fascinating dive into the effects of high carbohydrates vs high protein. again nothing to do with ketosis, but Interestingly enough it did find that testosterone levels where higher in men who followed a high carb vs high protein diet, which does raise a few questions about the classic “x grams per lb” of body weight figure you’ve mentioned in your conclusions, and generally that gets bandied about by the fitness industry, and more specifically people who sell protein powder (maybe i just solved that riddle about whether you where being intentionally misleading after all).

I did find this study, which would seem to support ketosis as increasing testosterone levels:

which would seem to run counter to your conclusions (and has the added benefit of being an actual study into the effects of the thing that you are talking about).

But honestly, anyone who reads this (i doubt the writer will have made it this far, the word count is clearly too high), the focus being placed on manipulation of testosterone by this article is bizarre, and obviously a transparent attempt to manipulate you by targeting your male insecurity. I found this article while trying to find some useful information on ketosis as a fat loss tool, as i’m finding some personal success with low carb and thinking about trying it (keto) out for part of my cut. I don’t know if its any good yet but i can tell you this guy most certainly does not. I’ve been into fitness most of my life and this garbage is everywhere, hes throwing out “GNRH” and FSH and talking about cortisol like hes a bloody professor of medical science, and not a barely sentient potato who learned how to google “testosterone production”.

I don’t normally post on these articles, but this poorly worded advert for protein powder really got on my nerves, perhaps you can tell. If just one person reads this and looks elsewhere for their information it will be worth the time it took me to write it. It’s garbage, written by sociopaths to sell you bollocks.

P.S. Marc buddy if you made it this far, i really enjoyed your statement about being contrary to the salesmen out there trying to sell you “stuff” and “Books” (or cryptonite as i assume people in your specific nietch like to refer to them) you really are a man of the people.

josh - August 22, 2019

these studies are stupid, because it takes a while of adaptation by the body to switch to burning fats instead of carbs… as nearly everyone is on a high carb diet and have ruined their metabolism and ability to burn fat. so basically, during the transition period (few weeks maybe?) eating low carb is basically starving your body…. it isnt getting the carbs for energy, and can’t properly utilise the fat.

all studies take regular people (high carb diet, can’t burnt fat)… switch them to low carb and measure results immediately… so they’re measuring the results while theyre in the transition period and essentially starving their body of fuel/energy. this will ruin anyones hormones temporarily… after 1-4 weeks ( sometimes longer) the body will adapt to be able to utilise fats for energy and this is when the real gains kick in. this is why you can’t always trust “science” and “science” can be manipulated to appear a certain way to meet what someone wants it to say.

studies should take people who have been on a keto diet for at least 3 months… preferably 6-12 months so we can guarantee their bodies are full adapted to fat burning. the results would be a lot different. remember there is a known withdrawal period when you switch from high carb to low carb/keto… you can suffer real withdrawal affects like headaches, fatigue, mood swings, cramps, increased stress etc while your body is “withdrawing” from the carbs and switching to burning fat…. this is the period where these studies take their readings/results.. no wonder they come back poor. its like taking a heroin addict off heroin and measuring hormones during the terrible withdrawal period and saying that their testosterone is down… so they should add in more heroin and heroin is good for testosterone and not having heroin is bad for testosterone …. (extreme example but you get the point)

im guessing you know this and are purposefully lying to people to sell a product.

Craig Carpenter - April 1, 2019

The only thing I can garner from this completely misleading article is that you want people to buy your products, go to your gym, or die horrible deaths from diabetes, obesity, and/or heart attack. A keto diet has been in use for as long as humans have been on earth and we have propagated the species just fine. A real foods diet of high fats and low carbs is the natural diet of homosapiens sapiens. It has only been in the last few thousand years and especially in the last 300 or so that humans have shifted to a diet consisting of 40 to 60 percent carbs. Do a bit of actual research into lipidology and the natural function of the digestive system. Then consider the lies that you’ve been told by the AMA, ADA, and AHA.

Soltura Cuba Travel - July 15, 2018

Fatty acids break down into glucose via gluconeogenesis. You seem to know what you are talking about, so one can only conclude that you are being intentionally misleading for personal gain.

Lowcarb - March 13, 2018

Aaron, Funny I am 61 have been doing Keto for 26 years. I had a Test check last year and it was 1097. High is 900. Lifetime Natural competitor tested over 30 times, NANBF Promoter. I find this article conflicting.

Go to Wikipedia and look up “Cholesterol”. It says it is the precursor to all Hormones Testosterone etc. Making up your calories of primarily plant food and lessor of Saturated Fat ( The type of fat is most important BTW) for a Natty would be less than optimal in my experience. The cookie cutter ratio here would put me at 45-80 fats. That is lowfat dieting of old and I was soft at contest and lost size and strength every time doing that. Once I went to more like 110-130 grams it was like doing gear in comparison. Using this I was Lean and hit PR’s the week of shows in the gym a sign of no loss of muscle and possible gains on a Prep.

A lot of it is age related. A late teen to mid 20’s guy if they cut our junk food and beer just about any diet will appear to work. This is how much of this is skewed. What works for a guy that is 35 should shed light on what is really the best and optimal for Natty’s.

John Best - October 11, 2017

I tried the drop factor diet last spring and loved it.

Aaron Miller - October 4, 2017

Hey Marc, if Keto diet kills testosterone and people say that low fat diet kills testosterone as well. Why is that? Would not keto raise testosterone if low fat diet kills test?

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