Articles, Blog

The Effect of Animal Protein on Stress Hormones, Testosterone, and Pregnancy

August 19, 2019

[Music] high protein diets during pregnancy helpful or harmful a question answered about forty years ago and the infamous Harlem trial of 1976 a randomized control trial of nutritional supplementation in pregnancy in a poor black urban population the study was begun at a time when protein was just assumed to be deficient in the diets of the poor had they actually analyzed their diets before they started they would have realized that wasn’t true but why let facts get in the way of assumptions so they split poor black pregnant women into three groups and gave them an extra forty grams of animal protein a day and basically a couple cans Venturer versus about six extra grams of animal protein or no extra protein and sat back and watched what happened the high protein group suffered an excess of very early premature births and associated infant deaths as well as significant growth retardation the babies that survived more protein meant more prematurity more deaths and more growth retardation and when kids grow up animal protein intake during pregnancy has been associated with children becoming overweight later in life and getting high blood pressure the offspring of mothers who reported eating more meat and fish had higher blood pressure in adulthood this was part of another failed dietary intervention trial in which mothers were advised to eat a pound of meat a day the increased weight gain and high blood pressure may be due to the obesity causing chemical pollutants and the meat supplies I’ve talked about before or the animal protein induced in the induce rise in the growth hormone igf-1 or it could be due to a steroid stress hormone called cortisol a single meal high in animal protein can nearly double the level of stress hormone in the blood within a half-hour of consumption much more than a meal closer to the recommended level of protein give someone a meal of crab meat tuna fish cottage cheese and the stress hormone levels shoot up but instead gives someone some barley soup and a vegetable stir-fry on rice and the stress hormone level goes down after the meal and imagine if you did the meat fish dairy meal after meal day after day you could chronically stimulate your stress response access and increase the release of vasoactive hormones that can increase your blood pressure and all that extra cortisol release has been linked to increased risk for elevated blood levels of insulin triglycerides and cholesterol if you take men on a high protein diet meat fish poultry egg whites and switch them to a high carb diet of bread vegetables fruit and sugary junk their cortisol levels drop about 1/4 within 10 days at the same time their testosterone levels shoot up by about the same amount high-protein diets suppress testosterone that’s why if you take men eating plant-based diets have them start eating meat every day their testosterone levels go down and actually some estrogens go up that’s why bodybuilders can get such low testosterone levels it’s not the steroids they’re taking if you look at natural bodybuilders who don’t use steroids 75 percent drop in testosterone levels in the months leading up to a competition right testosterone levels cut by more than half enough to drop a guy into an abnormally low range it’s ironic that they’re eating protein to look manly on the outside but it makes them less and less manly on the inside and from an obesity standpoint in general a drop in testosterone levels may increase the risk of gaining weight gaining body fat what does cortisol have to do with weight there’s actually a disease caused by having too much cortisol called Cushing’s syndrome and this is kind of a before and after in terms of abdominal obesity which is most of that white even in normal women though chronic stress chronic high cortisol levels can contribute to obesity and if they’re pregnant high meat low-carb diets may increase cortisol levels in the mom which can lead to inappropriate fetal exposure to cortisol which in turn can affect the developing fetus resetting their whole stress response thermostat leading to higher cortisol levels their whole life which can have serious health consequences it can stick with them their whole lives and indeed that’s what they found every maternal daily portion of meat and fish was associated with five percent higher cortisol levels in their children as much as thirty years later though green vegetable consumption was found to be protective higher meat and fish consumption like three servings a day compared to one or two was associated with significantly higher cortisol levels but eating greens every day appeared to blunt some of that excess stress response and they had adult children of mothers who ate a lot of meat during pregnancy don’t just walk around with higher stress hormone levels but also appear to react more negatively to whatever life throws at them if you put them through that Trier test which involves public speaking in front of a panel of judges followed by a live math exercise here’s the stress hormone responses in those moms who ate less than two servings of meat a day versus about two a day versus about two to three servings a day nope before the test started the two lower mother meat groups have started out about the same just walking around but they’re exaggerated cortisol responses was laid bare when exposed to a stressful situation now the real-world effects of this is that after that sort of test if you give people their own private snack buffet with fruits and veggies versus fatty sugary comfort foods like chocolate cake guess who eats less fruits and veggies those who have these high chronic stress levels cortisol has been implicated as a factor in motivating food intake even when you’re not really hungry so no surprise the animal protein intake during pregnancy may lead to larger weight gain for her children later in life and maybe even her grandchildren that’s how much the stress axis can get mucked around recent evidence suggests that long-term adverse consequences may not be limited to one generation the diet of a pregnant mother may affect the development and disease risk of her children and even her grandchildren ultimately these findings may shed light on a rapidly expanding epidemics of diabetes obesity and heart disease [Music] you


  • Reply LefkiosG January 18, 2017 at 1:12 pm

    Question: You suggest that high protein diets before competitions for bodybuilders is the cause of testosterone decrease, what about their abnormally low body fat levels? Could it be due to that as well? How can we be sure of the causality here? Did the paper that you got distinguish between that, did their methodology account for that in some way? Thanks.

  • Reply Eelke Aptroot January 18, 2017 at 1:14 pm

    And I thought the diets they fed us were hereditary…

  • Reply Emmi! January 18, 2017 at 1:15 pm

    If plant eaters have more testosterone then they are more susceptible to the conversion of DHT and therefore Male Pattern Baldness (?). Finasteride, an inhibitor of type II 5α-reductase, decreases serum and scalp DHT by inhibiting conversion of testosterone to DHT and improves hair of balding man (with very BAD side effects)
    So what happends to long term vegans then?

  • Reply Daniel Penhallurick January 18, 2017 at 1:22 pm

    another win for veggies!

  • Reply John Richards January 18, 2017 at 1:25 pm

    nice job on the video as always !!

  • Reply eder corrales January 18, 2017 at 1:29 pm


  • Reply Miko January 18, 2017 at 2:02 pm

    Very shocking yet vital information I think every one should know about.

  • Reply Lichtblick January 18, 2017 at 2:13 pm

    Thats why i can't get kids. In germany kindergarten are not vegan friendly. I will not let my kids eat animal foods!

  • Reply Ronnie & Minh January 18, 2017 at 2:23 pm

    Eating meat is bad …. ok, got it.

  • Reply GoustiFruit φ January 18, 2017 at 2:32 pm

    "Ultimately, these findings may shed light on our rapidly expanding epidemics of diabetes, obesity and heart disease"… "and violence" I would add.

  • Reply Mike Blaid January 18, 2017 at 2:36 pm

    very informative always with awesome content Doc. But this is shamefu,l arent researchers not supposed to test on people if they assume outcome will be negative in result? oh, but its okay it's just poor people and they're black women shucks. its sickening. is this the tuskegee experiment.

  • Reply Suh-Tee-Bun January 18, 2017 at 2:41 pm

    they actually made people give a speech and then have a public math quiz, haha

  • Reply CHRISTIANNWO January 18, 2017 at 2:42 pm

    A pound of meat a day? That's a lot of meat, especially for a woman.

  • Reply Lloyd Naylor January 18, 2017 at 2:42 pm

    Leading up to a contest bodybuilders lower their carbs to create a calorie deficit to lower bodyfat(super low body fat can also reduce testosterone). So maybe these are additional contributers.

  • Reply CrazyPolishVEGAN January 18, 2017 at 3:17 pm

    My testosteron level is 1054 🙂 Plant based diet, active life, positive thinking, confidence, good sleep and good erection 🙂
    Vegan for life! <3

  • Reply Peggy Harter January 18, 2017 at 3:21 pm

    All I can say is "Wow", Now how to reverse the cumulative effect on post menopausal woman? Plant base ?

  • Reply Daniel S January 18, 2017 at 3:25 pm

    6:40 Well, now we can peg the birth of the millennial generation to a cause.

  • Reply RANDOLPH TORRES January 18, 2017 at 3:30 pm


  • Reply Adam Waddington January 18, 2017 at 3:38 pm

    To be fair, the reason bodybuilder's testosterone levels drop leading into a competition is because they're dieting down to levels of bodyfat between 5-7%, which will definitely cause a drop in testosterone…

  • Reply FreeD00M January 18, 2017 at 3:48 pm

    Sausages are soft, cucumbers and hard…

  • Reply Rosanna A January 18, 2017 at 3:56 pm

    their testosterone drops because they are losing weight for a competition, not because of protein intake.

  • Reply Jean C January 18, 2017 at 4:05 pm


  • Reply jannu jokunen January 18, 2017 at 4:06 pm

    bodybuilders 1 month before competition basically starve themselfs.. it dont think its a very good argument. it's prepping for competition, and trying to get all excess water etc. out of the body.

  • Reply A A January 18, 2017 at 4:18 pm

    A pound of meat a day? Jeez.

  • Reply Matthew Cannings January 18, 2017 at 4:42 pm

    Are the negative effects of high protein diets exclusive to meat and dairy sources of protein or would a high protein plant based diet have similar consequences?

  • Reply jpmathematician January 18, 2017 at 4:54 pm

    Great video!!

  • Reply Elise Wouters January 18, 2017 at 5:10 pm

    Fun lift effective mechanism dynamics incredible accident suburb even

  • Reply David Sacras January 18, 2017 at 5:26 pm

    You cherry picked in the bodybuilding study. Since that drops occurs due to a high calorie deficit they go into in order to achieve super low body fat percentages for the show. In that study he dropped do 4.6 percent bodyfat that obviously interferes with his testosterone. Vegan and part time bodybuilder here.

  • Reply FreedomFisher January 18, 2017 at 5:33 pm

    How about nuts? How do they affect stress hormones and testosterone? Thank you in advanced!

  • Reply ariel January 18, 2017 at 6:08 pm

    when will he do his 2017 presentation

  • Reply Aldi More January 18, 2017 at 6:21 pm

    Scary stuff. No wonder I am snacking on romaine and cherry tomatoes. Just wish I had known all this when I was younger. Thank you so much Dr Greger!

  • Reply NexisFilms January 18, 2017 at 6:41 pm

    Dr. Greger, please do more videos on Bodybuilding and adequate protein intake !
    What plant foods have the highest protein ? etc …

  • Reply Brooklyn Hudson January 18, 2017 at 7:46 pm

    Please do a video on the effects of a plant based diet on patients with high cortisol. Can it be reversed? Whether caused by your mother's diet or trauma, can the plant based diet reduce high cortisol levels?

  • Reply aprilracine January 18, 2017 at 7:59 pm

    "All which can be prevented and some even reverse by a plant based diet."

  • Reply Peter Rabitt January 18, 2017 at 9:01 pm

    My anxiety disorder simply vanished as soon as I changed my diet to WFPB.

  • Reply Annie Mouse January 18, 2017 at 9:33 pm

    vegan but still stupidly stressed and anxious 🙁

  • Reply burnsport1 January 18, 2017 at 9:55 pm

    Fantastic – would love to see a video on the mechanisms for the hormone drops. You mentioned one: pollutants in meat

  • Reply dcgfhgjnzgfnjcbgn January 18, 2017 at 9:59 pm

    Sounds like they need to control for the fact that the mothers are passing on their eating habits. That could be the cause of their children being more obese, and having higher cortisol levels. It may be completely environmental, and not hereditary.

  • Reply Feldenkrais with Alfons January 18, 2017 at 10:06 pm

    "But why let facts get in the way of assumptions" epic word play

  • Reply noni1smd January 18, 2017 at 10:28 pm

    of course the study was done on black pregnant women….but hey…racism isn't real or anything. VEGANISM is a huge way to level out the harm done by white supremacy.

  • Reply Mark Gray January 18, 2017 at 10:37 pm

    only 200000 subscribers, thats crazy. this is stuff everybody needs to know.

  • Reply White Kita January 18, 2017 at 10:54 pm

    13 paleo fans so far hated this video….LOL…..oh yea and yes its true,… Vegan men don't need help to get it up and have much more endurance in bed,….(as long as they also stay away from drugs, alcohol, and especially porn of course.)

  • Reply TallWaters January 18, 2017 at 11:13 pm

    Bodybuilder test levels are low pre contest because of their low body fat

  • Reply One Needle January 19, 2017 at 12:22 am

    Doctor, does meat consumption exacerbate the symptoms of bipolar disorder.

  • Reply mryodak January 19, 2017 at 3:44 am

    What about legumes and tofu? Is non-animal protein bad for you?

  • Reply mryodak January 19, 2017 at 4:11 am

    Hmmm. But isn't testosteron produced from cholestrol, which increases by comsumption of animal protein?

  • Reply Here's Hot Rod January 19, 2017 at 4:57 am

    I read that vegans and vegeterians tear more easily while giving birth.

  • Reply Dustin January 19, 2017 at 8:27 am

    In reference to the low testosterone in natural bodybuilders leading up to competition is this not potentially due to the very low levels of body fat from caloric restriction?

    Could you not also get a drop in testosterone from vegan bodybuilders if they calorie restricted leading up to a competition and dropped their bodyfat lower than is healthy for the sake of aesthetics?

  • Reply Solange BV January 19, 2017 at 11:20 am

    Hello Dr. Greger, thanks for the video! There must be a lot of work behind it.
    I have a request/suggestion for you and your team. Can you please publish some videos where you analyse studies that have different results from what you've just said, and explain how they got those results? Many thanks to you and your team! Solange

  • Reply Des Troya January 19, 2017 at 1:51 pm

    Great pseudo science Dr.  But if I'm at work do I want to eat a meal that will reduce my stress hormones (possibly putting me to sleep) or increase them (keeping me alert)?  I don't see how stress alone is an argument to never eat meat.

  • Reply View Lo January 19, 2017 at 4:27 pm

    informative as always. but that clip of that spider was uncalled for lol

  • Reply Anachronism January 20, 2017 at 4:04 am

    I have so many questions. Interesting studies, but was that from natural meat or processed meat with steroids, antibiotics and a grain fed diet? Also, this is under the assumption that high protein diets can only be attained through animal protein. I read a study about Eskimos having a lower rate of heart disease despite a primary diet of meat in cold climates.

  • Reply david dawes January 20, 2017 at 5:50 am

    What is the verdict on mistletoe for cancer?

  • Reply M Ulysse January 20, 2017 at 9:46 am

    All I can trust is my own body. I'm going to dry fast and detox for a couple days and then ask and listen to what my body is asking for.

  • Reply vegansoul January 20, 2017 at 1:13 pm


  • Reply D Master January 21, 2017 at 6:49 am

    that means someone with prostate cancer may not need to take testosterone lowering drugs if they eat enough meat.

  • Reply Chalisse Monroe January 21, 2017 at 9:01 am

    My husband has been diagnosed with Glucose-6-phosphate dehydrogenase deficiency. Also known as G6PD. They say it is incurable! I wholly believe in nutritional healing via a plant base, vegan diet. Problem is beans, soy, and lentils are some of the main triggers they say he must avoid! Would a vegan diet alleviate the oxidative stress enough to balance the consumption of beans & lentils??? I need some serious help addressing this!!! The conventional Dr.s have been useless.

  • Reply JaxxoDam January 21, 2017 at 12:59 pm

    I think Dr. Greger is very smart and almost always tells the truth. But I think that bodybuilders who up to a competition loose their test levels, is not because of high meat diet, it's because they train so hard, and eat so little. Think about it, natural bodybuilders eats as much meat in the off season (hence they should also have low test in off-season) but the study suggests it's first up to competition they loose test levels.

  • Reply Anthony Romano January 21, 2017 at 5:42 pm

    The lies the food and drug administration and the meat and dairy industry fed us for decades is ingrained in the culture.

  • Reply Kodi O'Neil January 22, 2017 at 2:37 am

    Hey Dr. Greger, do you think that the data showing drops in natural body builder's testosterone are from them going off cycle from their steroids to avoid getting caught with substances during the drug tests before a competition?

  • Reply omegafile January 23, 2017 at 1:37 am

    This is baloney. The truth is the complete opposite. It's eating grains, carbs and sugars that make you fat plain and simple. The more you eat of it the sooner you will die. Farmers know this for centuries. You need fat and protein more than you need carbs and the type of protein makes a difference in the body's ability to break it down into it's individual amino acids. Vegetable proteins are poor sources of nutrition and are usually the ones causing your health problems to begin with. Stick with animal proteins and fats.

  • Reply CV January 23, 2017 at 6:40 pm

    Any studies on a High Protein vegan diet. Using Vegan protein powders?

  • Reply Ivan B January 24, 2017 at 8:30 pm

    I will tell you right now I'm a pretty objective person and having extensive experience in bodybuilding I will say that Dr. Greger is absolutely right on in this video. I used to feel so stressed when I was eating animal foods but now being plant-based it's much much less. Also having competed nationally in many NPC shows I recall seeing many former pro and offseason IFBB bodybuilders, and virtually all of them were not lean or in good shape. One of them told me his testosterone plummeted once he stopped taking anabolic steroids and competing and his body fat level was higher and his waist was like a balloon. So this is really fascinating stuff and I will also say that it used to be so hard for me to get leaner eating an animal-based diet whereas now eating plant-based it's incredibly easy to be leaner. It's crazy. So I can vouch for what Dr. Greger is saying here. And many of these oxymoronic ideas are actually not so far-fetched. I will continue to follow the research and see where it leads but certainly this video is prognostic.

  • Reply Kira Page January 26, 2017 at 12:26 pm

    This has me worried. I am a vegan now and eat for the most part Whole Foods but during my first pregnancy I ate a lot of fast food during first and third trimester, and for my second trimester I followed (not so) nourishing traditions. This plan emphasizes eating full fat raw dairy products, taking fish oil, eating meat, bone broth, animal livers, EGGS, etc. To hear now that my poor sweet baby boy could have long term health problems from the foods I mistakenly ate during pregnancy kills me inside. I guess the ultimate question would be since I am feeding him a plant based diet now will he still be facing these health problems down the road?

  • Reply Sara Sinclair January 27, 2017 at 8:26 pm

    Any male bodybuilder can tell you their testosterone levels drop when they're near contest weight. That's a given. But most likely due to a LOW FAT diet and extremely low body fat. Most contest diets are low in fat and carbs, so they have to eat protein as their main macronutrient. This study is a terrible example. Bodybuilders do the work in their OFFSEASON to build all the muscle and shed the fat over a 6 month period for a competition. Having muscle and looking 'manly' has nothing to do with testosterone levels. Booooooooo

  • Reply KungFuChess January 29, 2017 at 3:55 pm

    Bodybuilders continually pound their bodies with high stress workouts which probably raises cortisol more then the protein intake

  • Reply 🐺 February 2, 2017 at 7:58 pm

    Natural bodybuilders testosterone drop because their diet is extreme before competition.
    Not because of eating meat.
    I eat plenty of meat and my test levels are higher than normal.

  • Reply Tico Burch February 3, 2017 at 6:42 pm

    Can you please do more videos on multiple sclerosis? I'm recently diagnosed and all my specialist say stay off the internet for false and inaccurate hope/diagnosis but only tell me to eat clean and to focus on overall healthy eating vs a specific diet. Vitamins were suggested but not required. I was told to start taking probiotics. I'm so lost and confused and afraid…pleas help

  • Reply Caleb Brandalise February 4, 2017 at 7:33 am

    omg yesssssss

  • Reply Sheryl Gething February 5, 2017 at 6:41 pm

    thankyou Dr.Greger🙏

  • Reply bedouin4life February 9, 2017 at 11:26 am

    organic is good. those studies didnt study thzt

  • Reply Benzo Stanbury March 5, 2017 at 12:45 am

    Might the rapid loss of weight in-and-of-itself contribute to lower testosterone? And what about the idea that although vegan eaters have higher testosterone and lower cortisol, they also have higher sex hormone binding globulin? I appreciate citations to address these issues… and that's why I like this channel, because its citations are robust!

  • Reply Calin 12 March 7, 2017 at 6:16 pm

    Isn't the lower testosteron in bodybuilders close to competition the result of a low body fat?

  • Reply Rob Lim July 12, 2017 at 4:48 pm

    I think what the study about bodybuilders leaves out is that they dieted down to sub5% body fat which would crash testosterone levels as well

  • Reply COMING November 1, 2017 at 11:57 pm

    My psoriasis and chronic insomnia went away thanks to plant based diet. I've become a plant based dietarian for life

  • Reply Laurice January 27, 2018 at 5:50 am

    This is a Profound Revelation for low income families and for the African American communities!

  • Reply W April 14, 2018 at 5:14 pm

    can you do a video on protein powders?

  • Reply Marcelo Medina April 28, 2018 at 7:17 pm

    fuck "boosting foods", like meat.

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  • Reply fun in the sun May 24, 2018 at 6:42 pm

    This video made me think of the meat pushers of the 1950s, when my parents were growing up. My grandma was overweight, my mom is overweight, all my brothers and sisters are overweight. I'm the only one who is a normal weight. Like Dr McDougall says, "it's the food!"

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  • Reply UMU-i-D July 23, 2018 at 4:22 pm

    so I should eat more sugar, juices, bread, high carb foods and avoid meat?? That's ridiculous!

  • Reply Maureen K August 1, 2018 at 9:43 pm

    I only wish Dr. Greger and nutrition had been around when I was young!

  • Reply yaggle fraggle September 3, 2018 at 9:46 am

    I have like 4 lbs of protein power, but I guess I got to throw it away now.

    I've been lifting for 10 years and still look skinny. I've had ocd, depression, and suicidal thoughts since childhood. Have quit 3 jobs from social anxiety. Gynecomastia. If going vegan might help I guess it's worth a try.

  • Reply Emma T September 18, 2018 at 12:59 pm

    High protein diets are low in magnesium, that might have something to do with excess stress hormones.

  • Reply gabriel gagne February 20, 2019 at 8:04 pm

    I can’t get to the sources in this video, I’d like to look at the studies

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