Submitted by -LoveMeMore t3_z5rsad in askscience
I read that obese children, or children with a higher bmi start puberty earlier, and children who are underweight or have a lower bmi start later. Why exactly is this?
Comments
Material_Mongoose339 t1_ixz00dk wrote
Quick answer: additional fatty tissue can supply increased lipid levels, including cholesterol, which is the basis for sexual hormones synthesis. Moreover, fat tissue can itself synthesize some feminine hormone lookalikes that can trigger early puberty (this is also why obesity is a factor influencing male hormones).
Interesting-Month-56 t1_ixz6lwh wrote
In addition to this, obesity is generally an indicator that the child is well fed while being underweight is an indicator of malnutrition.
The decrease in the global average age of menarchy over the last 100 years has been postulated to be entirely due to improved overall nutrition, which would support such a view. It’s not clear from your post whether you’re just comparing overweight and underweight children or overweight to appropriate weight children
cabalavatar t1_ixzf4iv wrote
Higher BMI does not necessarily mean more fat. I was a very athletic and naturally large kid even before puberty, with a high BMI and little fat. See also bodybuilders, US football linebackers, rowers, etc.
BMI is just bad science, and the medical field would do well to scrap its use.
chazwomaq t1_ixzfaoy wrote
>From an evolutionary perspective, you want to grow to sexual maturity as quickly as possible,
This is not true. There is a tradeoff between reproducing early and growing a large body size. Both are advantageous, and so life history theory is all about managing such tradeoffs to maximise overall fitness.
Early sexual maturity (and small body size) is favoured when extrinsic mortality is high, and vice versa.
ImportanceAnxious t1_ixzfng9 wrote
We can’t rule out diet on this one. These days, meat products are full of artificial hormones. A child who eats more processed meat (and other processed foods) has the likelihood of being obese. Excess fat will store hormones (natural or synthetic) which can trick the body into a faster puberty.
Celcey t1_ixzjqai wrote
Obesity is not an indicator that a child is well fed, it’s a sign the child is over fed. And many, probably most, obese children are malnourished because they’re not eating nutrient dense food. So they’re getting calories, but not vitamins and minerals.
Interesting-Month-56 t1_ixzka4m wrote
Granted there is nuance and important detail missed in the generalization, more calories available while growing generally indicates better health than growth stunted by lack of calories.
I recognize that we have also gone from the sublime to the ridiculous and that some overweight kids have nutritional deficits. Don’t know how that affects onset of puberty though.
nicholsz t1_ixzkndy wrote
We understand that, but the endocrine system which evolved before Cheet-os doesn't.
-Metacelsus- t1_ixzkzrr wrote
Leptin is a hormone produced by fat that promotes the onset of puberty. See: https://www.sciencedirect.com/science/article/pii/S0018506X13000330
rymep t1_ixzmxcg wrote
The medical field doesn't use BMI for children (under 18) and understands what population it's not useful for. It's popular to bash on BMI, but for population level studies it's still a reasonably useful metric.
[deleted] t1_ixznfjw wrote
[removed]
[deleted] t1_ixznftf wrote
beara97 t1_ixzoi70 wrote
The way we understand obesity in general is outdated, BMI is a measure that works great on population statistic levels, but individuals tend to fall through the cracks in a lot of ways It details why BMI has issues, but then it pitches waist to height ratio as the new measure so 🤷🏾 https://www.medicalnewstoday.com/articles/265215#Waist-size-linked-to-diabetes-risk,-regardless-of-BMI
Anachronism-- t1_ixzskip wrote
There was a group of doctors who got sick of hearing “BMI doesn’t apply to me because I’m so muscular”. So anytime they heard that they pulled out the body fat calipers. The vast majority of these patients had unhealthy levels of body fat.
Edit - I can’t find the article and don’t remember the specifics but the main takeaway was of people who claimed BMI didn’t apply to them the vast majority where overfat.
jbsgc99 t1_ixzsvkj wrote
From the perspective of an organism that originated in a world where starvation was only a single misfortune away, calories are king.
[deleted] t1_ixzsykx wrote
[deleted]
Anachronism-- t1_ixzt6lb wrote
What is pseudoscience? Body fat? Skinfold caliper tests? Being overweight is unhealthy?
Dave30954 t1_ixzt8x7 wrote
Dairy products are also a factor here, such as milk. That milk is coming from the same cows that they’re pumping full of hormones and drugs to get them to produce as much milk and meat as possible.
Ok-Development-8238 t1_ixzty60 wrote
Just imagining an image of cavewomen gathering Cheetos from bushes, while the men hunt a bright orange, high cheetah
rymep t1_ixzu92b wrote
Why? if someone says "BMI is useless and doesn't apply to me" shouldn't they be happy the doctor is going to use another metric instead of just sticking to BMI?
That's what a good doctor should do, find another metric that the patient can relate to.
-LoveMeMore OP t1_ixzuktm wrote
I mean a higher muscle to fat ratio
DessaStrick t1_ixzvc79 wrote
Hah. Tell that to my pediatrician who was very focused on my BMI.
Also being an NP myself now, as an adult, have never heard of not using BMI below 18.
[deleted] t1_ixzyzy2 wrote
[removed]
[deleted] t1_ixzzfwe wrote
[removed]
hiricinee t1_ixzzrfn wrote
That's just it. The body is essentially made to survive, reproduce, and take care of offspring until they can do the same. Obesity from an evolutionary standpoint is a sign of success, or at least a sign that there's enough resources to go ahead reproducing. The biggest concern to the body reproducing until the last 120 years was not having enough calories to survive (or calorie proxies.)
OLAZ3000 t1_iy02fmi wrote
Actually this is not what current obesity research suggests... we actually don't entirely know why.
I do agree with you for prob 75% of obese children, but there are prob 25% for whom there are other factors we do not understand at play. (Google recent news on obsesity research.)
GoodGoodGoody t1_iy042k0 wrote
Your bias is interesting: the post topic is obesity which you call “well fed” and everything else you call “underweight”.
Emetics t1_iy05xhp wrote
During puberty, your bodys insulin levels naturally rise. Insulin is a hormone to tell your cells and body to grow and store energy.
A typical processed carb rich diet that obese people would eat tends to lead to chronically elevated insulin levels essentially to bring down the glucose, mimicking the effect of the signaling of puberty.
[deleted] t1_iy06o3l wrote
I always was a person with a “fast metabolism “ never could gain weight no matter how much I consumed. And believe me I tried. ( I’m in my Thirties now and finally starting gain weight ) and I remember I was a late bloomer like 14+ and slow and steady till about 25. It was rly annoying and I did have a lot of obese friends in childhood and they all hit puberty at 10-13 and fast. In high school was the worst. It def messed with my head and how insecure I was. Lol. I’m all good now but took enough time compared to others lol
[deleted] t1_iy07q2m wrote
[removed]
Misabi t1_iy08sge wrote
>In addition to this, obesity is generally an indicator that the child is well fed while being underweight is an indicator of malnutrition.
Interesting perspective. An alternative opinion: "Malnutrition is a state of the body in which due to insufficient supply or incorrect absorption of essential nutrients, the body composition changes and the body's functions are impaired. Malnutrition is associated not only with reduced body mass index but also with obesity." https://pubmed.ncbi.nlm.nih.gov/34749356/#:~:text=Malnutrition%20is%20a%20state%20of,index%20but%20also%20with%20obesity.
ProofJournalist t1_iy08vv9 wrote
I bet you'd report a doctor for hurting your feelings if they accurately diagnosed you with cancer
blazinshotguns t1_iy098h1 wrote
Excessive insulin production leads to low SHBG levels which increase free androgens thus inducing puberty.
Exactly the same cause of PCOS syndrome in females in most cases.
Anyone that says anything different has no idea what they are talking about
[deleted] t1_iy09cld wrote
A_Boojum_Snark t1_iy09fpb wrote
Not the one you replied to, but I've always heard "well fed" used with an implication of excess, not as to the quality or correctness.
That said I took their post as spoken from an evolutionary perspective: well fed = resources = begin reproduction sooner. In regards to the "goal" of evolution being reproduction, more food is always a good thing.
ImprovedPersonality t1_iy0b0p1 wrote
> And many, probably most, obese children are malnourished because they’re not eating nutrient dense food. So they’re getting calories, but not vitamins and minerals.
It’s not that hard to get enough protein, vitamins and minerals on the food intake required for obesity.
GoodGoodGoody t1_iy0bhe6 wrote
Youre really trying to square peg-round hole that one. Topic is obesity which they rounded down to well fed. They say everything else is underweight.
Then you went off topic; if the topic was well fed it would be just that. A morsel too much or a morsel too little would be immaterial with no automatic assumption of excess (which is entirely irrelevant to the topic at hand anyhow).
TC9095 t1_iy0c9tm wrote
I'm pretty sure 120 years ago kids were not stuffing there face with McDonald's. I really doubt there were overweight kids in that time. They did not eat sugar like we live off of today
[deleted] t1_iy0chno wrote
[removed]
[deleted] t1_iy0cnpb wrote
[removed]
ExKnockaroundGuy t1_iy0cxzo wrote
Just look at the sugar content of modern packaged foods and the newer GMO wheat spikes insulin levels creating fat storage. Look at pics of crowds like young people pre 1980 compared to 2022.
[deleted] t1_iy0cyz5 wrote
mothman83 t1_iy0d6gq wrote
you are completely misunderstanding the point.
​
Until 200 years ago, famine was a real issue even in wealthy nations. The body does not "understand" obesity. The body " goes" ( i mean no actual thought is involved obviously) " this is a time of plenty, better reproduce ASAP while the going is good".
hiricinee t1_iy0dbvw wrote
It's not hard to imagine, going as far back as you can, a highly successful hunter/gatherer tribe where a kid indulged on berries and meat until they got big enough to start puberty early. It'd be a lot harder without calorie dense foods, but the idea that a body can overweight itself into early puberty was still a real thing.
Dr_dillerborg t1_iy0eyse wrote
Well Hamburger Charlie was selling fast food hamburgers in 1885 - so technically kids could stuff their faces 120 years ago.
[deleted] t1_iy0hjnp wrote
[deleted]
jdubb999 t1_iy0inkt wrote
>These days, meat products are full of artificial hormones
Simply put, this is absolute horseshit. Number one, all pork and chicken is 100% hormone free in the US, so we are only talking about beef. Beef production does allow the use of growth hormones, including bovine somatotropin, estrogen, and progesterone. Ingested hormones have very low bioavailability (ask any rancher or athlete.) The amount of measurable hormones in treated beef is only marginally higher than measurable levels in untreated beef. However, the reality is that your body produces far more estrogen and progesterone (on the order of tens of thousands at minimum) hormones than the beyond miniscule amount you would consume eating beef or drinking milk.
Bovine somatotropin (rBST) is a protein completely broken down (like any other protein) by our digestive systems, and are incapable of binding to human growth hormone receptors.
biguncutmonster t1_iy0ow55 wrote
Source on GMO wheat? There seems to always be some sort of fear mongering surrounding GMO
clullanc t1_iy0ufnl wrote
I really don’t think many children eat that way. Lack of exercise I can believe.
julius_sphincter t1_iy0zhf1 wrote
It's almost certainly sugar drinks/sodas that get most kids fat. I mean kids will eat straight dessert if you let them, but most parents know better than that.
What I see way way way too often is kids pounding sodas/gatorades/juices etc that are have more sugar than a bag of candy
bad_apiarist t1_iy100et wrote
This is true. In the pre-civilization past, substantial obesity was almost impossible. This is due to several aspects of modernity, and not just food availability:
- compared to us, ancient humans had to spend a LOT of energy just to survive. You want clothing? tools? food? Shelter? You're making it. You're finding it. You're preparing it. Every day. Or else you don't make it.
- Parasite & pathogen load. A substantial amount of body resources used to go to parasites like helminths, as well as to fighting off infections. In modern, post-industrial societies almost all parasites are simply eradicated. When you do get infections, you get medical care (antibiotics, vaccinations, antivirals, etc) that drastically reduce the strain on the immune system and energetic resources required.
- Obesity, at a certain point, is debilitating. But modern society makes such a life quite manageable. This was far less true in the distant past. No rascal scooters on the savanna. Many groups of humans were nomadic. If you can't walk and run reasonable well for hours at a time, you're in a lot of trouble.
[deleted] t1_iy10q2m wrote
[removed]
[deleted] t1_iy10q4m wrote
[removed]
Ok-Development-8238 t1_iy11blo wrote
I tell my anthro students that all the time: there’s a reason it’s so goddamned hard to lose weight. For most of the past 3.8 billion years, your ancestors & their relatives were more likely to starve than have way too much
Still fascinating to me that the brain operates on 20 watts
eddie3737 t1_iy11o78 wrote
The decreased average age of menarche is caused by excess of carb intake/decrease in insulin sensitivity. As someone else said many obese children are malnourished from a lack of nutrient dense foods
Ragnarotico t1_iy14dfw wrote
>From an evolutionary perspective, you want to grow to sexual maturity as quickly as possible, so you can pass on your genes before you potentially get eaten by a predator or something.
This is such a false and generalized statement. This isn't true for all animals and certainly not for human females specifically who need to develop hips wide enough to pass a baby's head through.
jduff1009 t1_iy15wzj wrote
It’s actually not hard to lose weight. Just consume less calories than you burn. Pretty basic math.
Ok-Development-8238 t1_iy16jc5 wrote
“It’s not hard to get over depression…just stop having negative thoughts!” 🤣
I have no problem fasting for 48 hours if need be…other people get crazy dizzy after six hours. But I have empathy for people whose psychology & physiology are different than mine
[deleted] t1_iy16pve wrote
[removed]
Saxamaphooone t1_iy170ji wrote
Juice is a really insidious one. On the surface it can sound like a healthier choice, but when you look deeper it becomes quite clear that it can be just as bad as drinks that are well-known to be full of sugar. I know someone who works in a dental office and they have to have “the juice talk” with parents countless times every year.
[deleted] t1_iy179aw wrote
[deleted] t1_iy1gstz wrote
SelectWay5519 t1_iy1i9c2 wrote
It depends on the type and variety of foods consumed, truly. The average American doesn't eat a diet diverse or enriched enough to meet all the basic requirements in calcium, potassium, Vitamin D and fiber for example.
[deleted] t1_iy1n1a0 wrote
[removed]
Celcey t1_iy1nq72 wrote
To an extent. There's a reason our bodies are designed to crave carbs, after all. But in today's food environment, calories can be a big problem. We really don't need as many as one would think.
[deleted] t1_iy1o95x wrote
[removed]
[deleted] t1_iy1ofq6 wrote
[removed]
riotousgrowlz t1_iy1rglb wrote
It’s actually much more complex than CICO. Your metabolism shifts as you lose weight and at a certain point it gets harder and harder to lose each additional pound. If you gain weight back (as most people do) your metabolism doesn’t have a corresponding increase so weight cycling actually results in more weight gain over time than making no changes. The hormones that control hunger are also affected by weight cycling and you can get hungrier the more you crash diet and it is HARD to do anything else competently while experiencing hunger pains. So, it’s not really simple math, there are so many more variables at play than simply calories in and calories out.
NightlyNate t1_iy1ryj2 wrote
However, without a healthy diet containing fiber and protein, which satiates hunger longer, people eat more unhealthy (ultra-processed) food which contains fats and sugars and calories, which is packed with fats and calories, which doesn't satiate hunger, which turns into a cycle. Especially if you buy nutrient deficient foods like microwavable dinners and processed products like those.
​
I hope I make sense.
riotousgrowlz t1_iy1t1u6 wrote
Sure but that’s not a problem solvable at an individual level— we need structural changes to help keep kids healthy. Long recess, more (non-traumatic) physical education, healthy school lunches, walkable cities, shorter workdays, regulations on advertising sugary foods to kids, reduction in environmental toxins that contribute to asthma, safe bike infrastructure, subsidies on fresh fruits and vegetables, etc. all would have an impact. But right now most obesity public health policy seems to “eat fewer calories dummy” followed up by a shocked pikachu face when that seems to have no impact.
Xxazn4lyfe51xX t1_iy1vowh wrote
This is probably not the reason. We don't really know what exactly triggers puberty yet. While adipose tissue is responsible for aromatization of androgens into estrogens, the feedback for this to happen is not present until after puberty.
beara97 t1_iy1z2ga wrote
Its not 99% did you read the article?
geekygirl79 t1_iy216bi wrote
Obesity can lead to early puberty in girls and delayed puberty in boys. Fat cells do produce a weak estrogen (estrone). But the hypothalamus (the center in the brain that is the master control of pituitary-gonad function) responds to a minimum body fat percentage that signals sufficient raw material to initiate reproductive life.
[deleted] t1_iy22ku5 wrote
[removed]
[deleted] t1_iy2a05e wrote
[removed]
throwaway92715 t1_iy2aevz wrote
Yeah and obviously if the hormones are in the meat they are in the milk too. Did you know that all the manure gets dumped into waterways as well? So that hormones even get picked up in fish and algae
throwaway92715 t1_iy2atkj wrote
Honestly none of that makes any sense. Because even if being fat allowed you to mature faster and pass on your genes quicker, you would not be able to run fast enough to keep up with your potential mates. Unless the individual was able to somehow keep their sperm in a chilled storage unit of some kind, there is no way that they would ever be able to deliver on that promise. So, evolutionarily speaking, they would likely not be able to protect any children they had from mountain lions. It is more likely the case that the corellation between BMI and reproductive success came about during the Ice Age, when it was very cold and extra layers of fat were needed to survive the winter.
throwaway92715 t1_iy2avrq wrote
You are right that BMI is outdated. It was more accurate back in 1981 than it is now.
throwaway92715 t1_iy2b683 wrote
Does that explain why there was an increased incidence of gynecomastia among prepubescent boys in the American southeast as documented in the seminal 1981 study by Baker, Simmons et al?
Aggravating_Paint_44 t1_iy2e4oc wrote
Thanks I’m cured
OLAZ3000 t1_iy2frf5 wrote
Google "recent obesity research news" for conclusions from a conference of scientists who study this who disagree with you.
ETA: link https://www.nytimes.com/2022/11/21/opinion/obesity-cause.html
chazwomaq t1_iy2x2rc wrote
My argument is basic life history theory. It may not make sense to you, but there is plenty of material out there to learn about it.
Interesting-Month-56 t1_iy2ycbk wrote
Yes, this exactly, thanks
[deleted] t1_iy45md5 wrote
[removed]
Celcey t1_iy4apx5 wrote
100% agree. We have a societal problem that is currently only solvable on an individual level, and that's just not gonna fly.
No-Cress3750 t1_iy70utf wrote
Those artificial hormones affects the human growth hormone ( testosterone & estrogen ). The effect’s are visible in females but how does it possibly affect males?
[deleted] t1_iy9wtr7 wrote
[removed]
st4n13l t1_ixyykqj wrote
I believe the data suggests this is true for girls, but the data is inconclusive for boys.
>“We found that in mid- to late puberty, girls with greater total body fat demonstrated higher levels of some reproductive hormones including follicle-stimulating hormone (FSH), inhibin B and male-like hormones such as testosterone."
>The researchers found that girls with higher total body fat had differences in reproductive hormone levels, developed mature breasts more slowly and got their first period earlier than girls with lower total body fat.
Obesity may affect puberty timing and hormones in girls