Left to their own devices, personalization filters serve up a kind of invisible autopropaganda, indoctrinating us with our own ideas, amplifying our desire for things that are familiar and leaving us oblivious to the dangers lurking in the dark territory of the unknown.”
-Eli Pariser


A lot of folks in the low carb camp shared the study below. It ran across my newsfeed and I got tagged in it multiple times. The headline grabbed me. It had this “Oh shit the world is ending type feel.” It was usually shared with one liners like. Eeeeek glucose is the devil.


Abrupt decrease in serum testosterone levels after an oral glucose load in men: implications for screening for hypogonadalism

-Caronia et al. 2013


…implications for screening for hypogonadalism. I’ll just let that second half linger for a bit.


When I see these type of shares the main thing I see is bias.

BUT let’s critique this study and really present the facts here so people have a good idea of what this study really found and what it did not find.

First off, it is a very interesting acute study with somewhat questionable statistics and a crazy heterogenous (different) spread of a population. One of the biggest things to mention is that the main goal of the study was to just assess from a diagnostic standpoint can ingesting a large bolus of sugar acutely affect testosterone readings. This is a very needed question to investigate because inside the medical model right now testosterone is not a required fasting draw.

They ran a bunch of one ANOVAs when they should have ran a MANOVA or had some kind of adjustment to their p value for the amount of models that were run. Maybe their findings would have still been significant, but we don’t know. The fact that they ran ANOVAs could have been an honest mistake, it could have also been that the MANOVAs weren’t significant and therefore results wouldn’t have been published. I don’t know, but let’s give them the benefit of the doubt.

I like that that they looked at the drop in testosterone for all the groups. Solid.

BUT, who are these subjects, breaking down the table below is the real story and as always I wish we had individual data. First off, the data is displayed in European units so no one in the States can intuitively think about how high or low these values are (myself included). So we need to convert these values to help understand the population. At it’s heart the table shows that if you blow out men’s blood glucose control you are going to have problems. 403.6 pm/L is close to 60 µIU/mL on the insulin side and the average blood sugar hovered over 160 mg/dl for the entire OGTT. You would NEVER see this type of profile in a trained lean male athlete with some traps on him. AND, we know that going past 30 µIU/mL from an insulin standpoint doesn’t do anyone any good.  I would cannon ball into a bowl of fiber if any of my client’s blood sugar ever stuck above 150 for two hours.

So what’s the overall conclusion of this new information?

Acutely, a glucose party in unhealthy untrained men results in bad stuff. That’s actually powerful, useful, and interesting from a diagnostic standpoint. Don’t eat three bowls of cinnamon toast crunch and get your T tested unless you want to be put on TRT, then maybe it is a hack. It tells us nothing about chronic basal changes, however the research is there with type diabetics that if you wreck shop on 75 gram samples of sugar consumed alone for 20 years bad things are going to happen. Thanks.

This study did not show that ingesting 75 grams of carbohydrate in the form of real food within a meal has an impact on testosterone levels acutely. It did not show that athletes who are refueling and trying to maintain blood glucose post training should be worried about ingesting a faster carb sources.

Here is a study that shows the opposite, three days of intense training without carbs and you get a drop in testosterone.
Influence of dietary carbohydrate intake on the free testosterone: cortisol ratio responses to short-term intensive exercise training.

Lane et al. 2010
Now what happens if some 23 year old cat who loves lift reads this one sided post about sugar?


A light goes off in his post-bench press brain, “Oh Shit carbs are bad I better eliminate all carbs because it is going to drop my T and I know that I need to T to get more bigger.”


….and four days later in a pool of sweat he dropped his testosterone by 43%.


There is the real “oh shit” moment.


The unfortunate thing is that those are probably the readers paying attention to these posts.


Thought leaders have to be careful about what they share, we can’t just circulate headlines that we agree with. Yes, I just put myself in there as a thought leader but really all I am as a thought questioner and synthesizer. Thought leaders and those with large followerships have a responsibility to present the facts. All the facts. I know being polarizing is what sells and what gets you likes, but is it the right thing to do?
Is it why we got in this field?
To propagate what we believe in with one sentence headlines?



I’ll get off my soap box now because I have made this mistake many times and if I do it again in haste – call me out. Question everything I put out. Please!


Next and probably most importantly all of this data (even the study I linked) is acute!

We have very little idea of what happens over time (these studies are very expensive and hard to control, but far from impossible – they will come and then we will need many of them for other researchers to then run meta-analyses) and we have even less of an idea in athletes because no one studies athletes because we live in a disease based model where funding for these populations is scarce.
Thus, as a nutritionist, strength coach, or functional medicine practitioners who works with athletes what are we to do? We measure and we question, again, again, and again.

If you are a male and you are training and you face palm dextrose after you train and your sex hormones look great and you feel great, keep at it. If things aren’t great we have to look at the entire organism, it’s overall stress load, how it sleeps, how it lives, how it thinks, how it encounters and interacts with food.

If you are 50 pounds overweight and you can’t go a day without a 64 oz Dr. Pepper, that is  likely a very different story and we are going to have to have a come to Jesus conversation about how you live your life and why you think it is ok to make this decision.

In either case, we have to look at the individual and their environment, not just throw around a sledge hammer of carbohydrate consumption.



-Laurent Bannock

Drop Your Email Below for All The Bro Research Updates and Latest Articles

You're In!