Image Credit: Nanagyei / Flickr. This image has been modified.

Why Are Children Starting Puberty Earlier?

Early onset of puberty is considered a risk factor for a number of diseases in adulthood, including hormone-related cancers, a shorter lifespan, metabolic syndrome, and cardiovascular disease.

The conventional thinking has been that the age of puberty has been getting earlier and earlier because our children have been getting fatter and fatter. However, European kids are also getting heavier, yet there has not been a steady decline in puberty onset (see graphs here). So it may be less about how much kids are eating and more about what they’re eating.

The most consistent link between diet and premature puberty has been found to be animal protein consumption. Every gram of daily animal protein intake—that’s just like the weight of a paperclip—has been associated with a 17% increase in the risk of girls starting their periods earlier than age 12.

Why this link between animal protein and premature puberty? We know meat increases the level of IGF-1 and that alone is associated with early onset puberty. If you’re not familiar with insulin-like growth factor 1, I have a series of videos about the growth hormone (though mostly in relation to cancer risk). See, for example, The Answer to the Pritikin Puzzle and Cancer-Proofing Mutation.

The early onset of puberty in girls associated with animal protein consumption may also be due to endocrine disrupting chemical pollutants in the meat supply. Watch my 4-min video Protein, Puberty, and Pollutants.

For more videos on premature puberty see:

I talk more about endocrine disrupting chemicals in particular in:

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 – 2015 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, From Table to Able, and Food as Medicine.


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

32 responses to “Why Are Children Starting Puberty Earlier?

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  1. It is said that besides the above mentioned consequences of early onset of puberty another big problem would be that maids won’t grow in length more than one more year after menarche. Afterwards they wouldn’t grow any more. If this happens when being for instance only 11 years old, it
    could lead to a pretty short body length. Is there any science behind this? I’d regard this point as very important as maids soon become women and if they will have health problems in the distant future it is bad indeed, but if they don’t even enjoy a happy life until they get sick it is even worse – their love life and happiness would be affected.

    1. yes it is true that menarche permanently stunts the growth. which one of the worst reasons why artificially early menarche is so bad.

  2. At the time of the Revolutionary War, the average of menarche (when a girl gets her first period) was about 17. Around the 1900’s, in America, the average age was about 14 to 15. Currently it is about 11-14, but girls as young as 9 can get their periods now. Moreover, we are seeing signs of the start of puberty….hair under the arms, pubic hair, etc in girls as young as 6. It is due to the increased saturated fat in their diet. The more periods a girl has in her lifetime, the higher her risk of breast, uterine, and ovarian cancer. Plus, early menarche robs girls of their childhood.

    1. I am now 72, but my peers and I entered puberty at age 11. Today, many physicians are seeing signs of puberty in little girls age 3 and 4.

    2. There is zero evidence to support this. In fact, there is no evidence to support that saturated fat is harmful at all. The biggest heart study in the world found saturated fat and cholesterol to be protective!

      There is however, substantial evidence that all the soy, growth hormones and xenoestrogens in everything all around us are huge factors in our health. I’d start there.

      1. Actually, I agree with Padma, being another person that ACTUALLY WORKS with patients, I have helped deliver babies from 12 yr olds. We are seeing children as young as 8 yrs old in puberty. this was not common in the 70’s when I began practice. And BTW, There is no legitimate study I have ever seen that says saturated fat is protective, it is EB knowledge that saturated fat is very inflammatory and destructive to the inner lining of our arteries, that includes brain, heart, kidneys…

      2. I don’t think either saturated fat OR soy are the problem. There are societies that eat tons of saturated fat (Mongolians, Turkish herding peoples, the arctic peoples, herding peoples in Africa, and traditionally some native americans) who never had early puberty problems. On the other side of the coin, you have Chinese, Japanese, Korean, and other east Asian peoples who ate a ton of soy and rarely consumed animal protein (they called soy “the meat without a bone”) and they also did not have problems with early puberty. what is causing early puberty is the massive influx of petrochemicals into everyday life of so many, from the food made out of oil (the fertilizer and pesticide both being made out of oil, you are literally eating oil when you eat these plants) to the buildings made out of oil (vinyl and polyester carpet floors, plastic counter tops, vinyl chair seats, mattresses stuffed with polyfill and saturated in fire retardants) cars made out of oil (the dash, seats, etc all made from oil) and running on oil, the same at school and home, and eating out of plastic and cans that have xenoestrogenic effects on the health. oil is not good for us and every oil-based product has a xenoestrogenic response in the body and unfortunately our entire lifestyles are saturated with petroleum now, from our food to our environments, the clothes on our back, the soap, food containers, building materials, etc its all oil based unless you make a concerted effort to avoid it

    1. If you are consuming dairy products that have had added female and male hormones that would be a contributing factor. However, most of the female hormones in milk are there naturally due to the pregnancy. Most of today’s “improved” dairy cows are kept pregnant over 300 days of the year. So they are usually milked while pregnant. Pregnancy is a very high estrogenic state. Dr. Garvey would be more qualified as a gynecologist to comment further. Being nursed and pregnant at the same time is not a prescription for long and productive life. Most dairy cows are sent off to slaughter after only about 4 years. Of course they live longer then the male dairy cows who are diverted to veal production and live for about 6 months before slaughter.

  3. Remember, recombinant bovine growth hormone which was injecting into cows to force them to give more milk. This was implicated early on during the 1990’s. And came onto the market with Michael Taylor, now food czar for the U.S. FDA, but in the 1980’s, a lobbyist with Monsanto worked to get it widespread into dairy.

    This was the reason I began buying certified organic Organic Valley and Stonybrook Farms dairy milks and yogurt, and I was not alone.

    However, now with an injured spine, my calcium comes from beans, certain fruits, and mostly dark leafy greens. They don’t make my body hurt the way dairy did.

  4. the average menarche of the maasai is almost 14 years. considering their diets are almost entirely animal foods [high protein and high saturated fat] shouldnt their menache be somewhere around age…4?

    1. I couldn’t find any references on age of menarche for the Maasai but assuming 14 is accurate there are many reasons why it should be higher then folks on the standard american diet but not as high as those on a WFPD. The two that come to my mind are activity and calorie intake based on food availability. Photo’s of the Maasai show them to be very lean. Since fat cells produce estrogen women who have higher per cent of body fat will have higher estrogen levels. As Jeff Novick points out so well in his Calorie Density DVD you can eat higher calorie dense foods if your physical activity level is high enough. Like any complex system there are many factors contributing to the outcome.

      1. The Massai consume about 3500 calories per day and though “active” in the sense that they walk a lot, they aren’t as active as American athletes. The Massai are lean while eating crazy levels of saturated fat.

  5. This article sadly conflates modern, industrially produced, hormone-laden animal foods with ALL animal foods. It’s not like humans haven’t been eating meat, dairy, fish and eggs for, oh, thousands and thousands of years now. Mongolians, Maasai, and other heavy meat eaters don’t have early puberty, so this theory, without qualification, is bunk.

    And the author hasn’t even factored in the fact that almost everything processed contains some form of SOY now–a known source of phytoestrogens. Nor considered all the industrial chemicals used in the U.S. in everything from furniture to clothing that are known xenoestrogens! We can’t just lay it all on animal protein, it doesn’t make good sense or science.

    It is totally possible to get wholesome meat, dairy, fish and eggs that haven’t been tainted by industrial chemicals, hormones and soy additives. Just ask your local family farmer.

    1. Ignoring the fact that you did not cite any evidence for your claims, the issues primarily discussed here do not have too much to do with contamination. The most convincing evidence to cut out animal products is ubiquitous among factory farmed meats and organic grass fed meats. That issue being endotoxemia and elevated IGF-1.

      In addition, human evidence shows that soy phytoestregons do not function like xenoestrogens and are beneficial to ones health and negligible in terms of negatively effecting hormonal balances. This remains true as long as one is below the 3-5 serving per day mark. After this point, one can expect raised IGF-1 levels which in turn may affect early onset of puberty in children and promote tumor growth. This is true due to its protein quality, not necessarily the phytoestrogens.

      In addition, poultry is a highly concentrated source of arachidonic acid which is highly inflammatory.

    2. Meat eating is only in recent human history, there are only scant findings before a few hundred years ago. Not too many humans can run down a deer or even a rabbit, the muscles in our legs are not designed to do such a thing, but our hands are perfectly designed to grab those apples off a tree, or our teeth to chew on a handful of grass seeds. Our intestines, gastric juices, pancreatic enzymes, and bacterial flora are perfect to digest fiber in plants and fruits, not decayed meat. Only a carnivore can eat an animal carcass that has sat in the sun for a week, guess what would happen to you!

    1. It certainly could be a contributory factor along with many others. Since it has been introduced into the food chain relatively recently compared to the declining rates of puberty it most likely isn’t a major one. That said I advise patients to avoid it applying the precautionary principle.

        1. I did not see this early puberty in vegan children, mostly overweight flesheating children. Everyone was exposed to BPA without realizing it back then, even the veggie kids. 30 yrs ago when I worked at a city hospital we were helping pregnant 12-13 yr olds deliver babies. In MHO, believing meat is ok to feed young girls is living in a fool’s paradise. Recently, I saw a little girl that was months from puberty at 8 years old, we see that more and more at 9 and up, but 8 really throws you. I hate to say this, but this information has been out for decades, meat eaters are fools

          1. I would add those who eat dairy and eggs to your list as well. I think they are only fools once they learn about the dangers and continue to consume them. Unfortunately many health care professionals are missing the opportunity to point out the way to eat as well as its importance.

          2. Dr.s suspected my 12yr old of having underlying chronic illness because she had not yet reached menarche. 13 1/2 now and signs are there but she is hoping not to deal with it til after 14 like her mother and grandmother. Both her and I are vegan, grandmother not but in postwar Germany everyone virtually so.

            1. It’s quantity too. Meat used to be an occasional treat or at most a flavoring, not the center of the meal 3X daily! Even carnivores only eat meat a few times a week if they’re lucky!

  6. i don’t think it is milk and meat in general that are causing early puberty. there are societies that consume almost nothing but milk and meat (Mongolian, African herders, native americans who ate so little starch that today they are high risk for diabetes, and inuit almost purely meat and fish) and I don’t think these traditional societies ever had a problem with menstruating 9 year olds. The reason we are seeing precocious puberty is due to modern pollutants that mess with the endocrine system. Petrochemicals mimic estrogens, are xenoestrogens. Also we feed kids foods that make them obese and body fat actually makes some of its own estrogen. Kids don’t walk to school or play outside like they used to because of fear of molestors and parents getting charged with neglect and their kids being put in CPS if they walk or play by themselves in their neighborhoods. So, we are making kids fat and putting them into early puberty by our lifestyles and dependence on petroleum products in our entire lifestyle, most parents don’t even understand what xenoestrogens they are exposing their kids to with a plastic baby bottle filled with warm formula made from a factory farmed cow or soy. the moms rub petroleum based lotion on their bellies when pregnant and use chemical air fresheners in the house. these are all xenoestrogenic. we cant go raising humans in a soup of xenoestrogens and also make them obese through too much sugar and not enough activity (and not enough vitamin D due to being inside all day) and not expect bad results, in this case, a drastically lowered age of puberty has proven to be the result.

  7. This comment thread is literally hilarious.

    It’s the dairy. No it’s the petrochemicals. No it’s the hormones fed the cattle. No it’s the meat. No (insert “tribe” or exotic culture but with no sources cited”) have their periods at age 17. Or 14. But they exercise a lot and eat lots of fat. But wait it’s the fact that it’s factory meat. No it’s not. It’s the BPA. No it’s the soy we eat. No it’s the soy the cows eat. 4 year olds have moustaches. I saw them.

    I’m sure if it had continued someone would have tied in GMOs, something Monsanto did, vaccines, fluoride, and maybe chemtrails.

    What to take from this? You don’t know. Most recent research cites stress and obesity as likely causes. No firm conclusions.

  8. Thank you for this article Dr Greger. I was born in 1965 and was fully grown by 1973 & started my period in 1975. I ate lots of meat and dairy but I was never overweight at all, most likely due to lots of exercise back then. Does developing so early make me more prone to breast cancer? I was one year post-menopause by age 50 so perhaps it helps that I didn’t have a late menopause?

  9. Could it be that cholesterol deficiency would cause menstruations not to appear at all? I am almost 17 years old (my BMI is 18) and I have not had my period yet. I have done many blood tests and endoscopies. The only thing they found, that could be the problem is that my estrogens are quite low. I was told that this is due to me not consuming enough colesterol. I have only been following plant-based diet for half a year ( even though i was vegetarian since I was ten). If this is true could I just consume more plant fat?

  10. Is it possible to reverse early puberty by switching to a mostly plant-based diet, removing dairy, etc.? Are there any actions a parent can take if their daughter seems to be entering puberty early? thank you.

  11. My daughter turned 12, she was on plant based diet for 1 year. Her breasts didn’t start growing yet. And she shorter then her peers. Can diet play a role in this?
    Where I can find more information about this?

    1. For girls, puberty generally starts sometime between 8 and 13 years of age, so you still have a time :) If you worry about that, a doctor visit might be helpful.

      Have a nice day, Alyona :)!


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