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> The results suggest that some previous studies, which have shown a strong link between childhood obesity and mental health, may not have fully accounted for family genetics and environmental factors

Paper: https://elifesciences.org/articles/74320

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The BMI system is so idiotic. Why does anyone care about this?

Unless they get bullied for it I guess.

Because on 8 years children and with 41,000 data from parents and children, you have to set a reference and the BMI in this case, can be considered acceptable.

Yep.

Also, ha ha.

What is your experience with the BMI system that makes you call it idiotic?

You guys need to go back to the drawing board on that one

we have multiple studies that are saying the same and multiple studies that are saying opposite... so yeah... science

It's a pretty good generalized first step of measuring overall health before going into blood pressure and lab tests. Especially with children as you need to make sure they're not lagging behind in weight as they grow.

BMI doesn’t consider the fat/lean mass but only the height and weight. Generally speaking can be inaccurate but for 8 years children is absolutely acceptable.

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I know what BMI is. I was trying to understand why that user thought it was idiotic. I’ve found it very useful for adults and children. However, for pediatric patients, the standard scale doesn’t apply, and percentiles are more useful. Lean patients with high BMIs are outliers and that is obvious clinically.

My point being, people keep talking about how BMI is a terrible metric but for most of the population, it is very useful.

Nobody in medicine I know agrees with that, but that's fine. You can have your opinion and maybe you're right. I'm just speaking from my own experience. Plus i literally have nothing to do with children. Still rubbish.

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Depends on the person. My daughter is 7 and she is 49 inches tall and 65lbs She is considered overweight by bmi standards but she does competitive gymnastics and competitive tumbling/trampoline never stops moving(she’s at the gym 12 hours a week and spends at least 6 hours a week at home practicing on her own) so she has a ton of muscle mass and 0 fat on her body. So for her bmi is bs. With that said you are right that with most kids/adults it can be helpfully but there is outliers like athletes that it doesn’t work for.

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BMI only took into account white men and wasn’t intended to be used widely/for everyone. It’s…trash.

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I disagree. There are adjustments for gender and age. You do have a point about race differences. But they just means that you have to be mindful when calculating risks when you look at the patient. Overall, it’s still a great measure. You’ll be hard pressed to find a clinically significant difference when you start looking at obese individuals (by BMI) regardless of gender/race.

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Your daughter sounds like a very focused athlete, but that's not the norm. Most children before 12 aren't working out so muscle to fat ratios tend to be a little more similar when they also have the same bmi numbers.

Probably says they or someone they know is obese and they dont like it

Stop trying normalize and excuse unhealthiness...especially when it comes to kids whos guardians should not be excused for allowing/encouraging/enabling it.

You asked EVERYONE you know in medicine about bmi? Kinda weird habit to be into, but ok.

It’s really not. If there is a suspicion that you might be underweight or overweight, you can easily check it thanks to BMI. If you are say bodybuilder, you are not going to care about your BMI.

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Yeah the social side of this seems to be completely ignored, there is significant impact to the mental state of a child based on their weight. This is coming from someone who's been through it....

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When the science is about diet and the mental health of children, it’s not gonna be very exact science.

But did they mention they literally have nothing to do with children.

They conveniently left out physical health, the primary concern for over-weight people. I worked at a daycare for like 12 years, when kids are over weight they can't run without taking breathes or similar things, they discourage themselves with zero outside input. Overweight kids lose more at kickball more, 4-square, tetherball, wallball and other popular schoolyard activities that kids use to judge themselves against others.

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Seriously.. What is this crap?

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Capitalism in conflict again. We have multiple studies saying veganism is good for you and multiple ones saying it's bad for you. Which one is it reddit?

being exact and saying the exact opposite are 2 absolutely different things...

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Social science studies should be taken with buckets of salt.

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So many people blazing right past the nuance and calling this study wrong. In fairness, that title doesn't do any favors.

1. There is obviously a correlation between obesity and mental health disorders. The study doesn't deny this.

> Children with obesity are more likely to be diagnosed with depression, anxiety, or attention-deficit hyperactivity disorder (ADHD). But the nature of the relationship between obesity and these mental health conditions is not clear. Obesity might contribute to mental health symptoms, or vice versa. Alternatively, a child's environment might contribute to both obesity and mood and behavioural disorders.

2. All the children studied were 8 years old, and from Norway. This means results may differ for different age groups and different cultures. (Right, Americans? You weren't thinking this study was all about you, right?)

> Dr Hughes and colleagues examined genetic and mental health data from 41,000 eight-year-old children and their parents from the Norwegian Mother, Father, and Child Cohort Study and Medical Birth Registry of Norway. They assessed the relationship between children's body mass index (BMI) – a ratio of weight and height – and symptoms of depression, anxiety and ADHD.

> ...

> "At least for this age group, the impact of a child’s own BMI appears small. For older children and adolescents, it could be more important," said Neil Davies, Professor at University College London (UCL)

3. The study focuses almost entirely on the link between BMI and symptoms of depression, anxiety, or ADHD.

> The analysis found a minimal effect of a child's own BMI on their anxiety symptoms. There was also conflicting evidence about whether a child's BMI influenced their depressive or ADHD symptoms. This suggests that policies aiming to reduce childhood obesity are unlikely to have a big impact on the prevalence of these conditions.

4. The conclusion does not rule out a correlation between obesity and mental health. The conclusion is that there are underlying environmental causes at play that are better targets to fix both problems. Fixing obesity crises may not improve mental health issues, and fixing widespread mental health issues won't necessarily improve obesity statistics.

> "Our results suggest that interventions designed to reduce child obesity are unlikely to make big improvements in child mental health. On the other hand, policies which target social and environmental factors linked to higher body weights, and which target poor child mental health directly, may be more beneficial," Hughes concluded

How is it completely ignored? This study focused on links between BMI statistics and disorders like depression, anxiety, or ADHD. Wouldn't the effects of social issues (like bullying) be part of the diagnosis statistics, unless they explicitly isolated for it?

Nearly all studies should be taken with buckets of salt.

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Why? This result may not line up with what you agree with, but what did this study do wrong?

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There is a difference in what kind of rigor can be expected though. Well over 90% of biology, chemistry, and physics experiments are controlled and replicatable. Social science data is a lot less clean cut.

No they didn’t conveniently leave anything out. The study wasn’t meant to answer every direct/indirect health related outcome of BMI.

Studies should be viewed independently, and collectively we can form broader conclusions. But it is fine for a study to only look at behavioral health affects of obesity, it doesn’t need to do the obligatory physical affects to make it valid.

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Right, fascists and communists always held uniform scientific views./s

Certainly, yes. But I'll be devil's postmodern advocate and say to be wary of all science which claims to be wholly objective and without influence.

I think a lot of the effects of bullying translate into anxiety, depression and other disorders with a delay. I think they establish a baseline low esteem which in time can contribute to other mental health issues. In speculating.

Welcome to diet and mental health science. I don’t know what else you want me to say.

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The poster is saying to stop telling everyone it's ok to be fat. It's the same notion as "everyone is beautiful, no matter your weight". It's not ok to be fat unless you have some underlying disease that makes it impossible to lose weight. Society has shifted to make everyone think it's ok to be obese. It's not ok. You are killing yourself and creating a bad image for kids to also think it's ok.

Is feels like you didn't read the study.

Scientific rigor is objectively important. All good science is viewed through the lens of skepticism. I am in complete agreement with that.

Buckets of salt is probably undue skepticism for lab experiments though. All things should be checked, some aren’t. Science does reward work that shows flaws in previous work though. I don’t believe headlines, but if I read a research article and the methods and results seem reasonable then I’ll believe it until other data contradicts it.

Exactly it’s important to understand how bmi effects different health outcomes.

Thank you. Some of the comments on this post are very vitriolic and strange, like they didn’t read the article.

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because most other studies suggest the opposite, and it says as much in the first couple paragraphs of the article,

>Children with obesity are more likely to be diagnosed with depression,
anxiety, or attention-deficit hyperactivity disorder (ADHD). But the
nature of the relationship between obesity and these mental health
conditions is not clear. Obesity might contribute to mental health
symptoms, or vice versa.

It is, you’re right. But this study isn’t supposed to address all outcomes, so it’s stupid to complain about it. Just like studies relating BMI to physical health usually don’t incorporate the mental health impact into their analysis. Because it wasn’t in scope for the study.

If this was a dissertation on all health affects of BMI and it didn’t contain information on the physical aspects that would be an issue. But it isn’t, and the people complaining about it are making an issue out of nothing.

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No they didn't you are right. I was saying that conflicting interests will always produce results that benefit them. Capitalism is a vague term.

Good comments. Contradicting current research is always a red flag.

The paper does not dispute that children with obesity are more likely to be diagnosed with depression, though. That correlation is clear. The conclusion seemed to focus more on the causation aspect, suggesting that underlying environmental factors influence both mental health issues and obesity in a population. From the editor's notes:

> the study finds that previous estimates of the effect of BMI on childhood emotional and behavioural symptoms may have been overestimated due to confounding with the environment. Larger samples will be needed to determine whether there is a causal effect of BMI on childhood emotional or behavioural problems, and what size it is.

Which is very on point for this sub.

As a social scientist myself, what makes you say that?

I agree that you need to love yourself no matter your weight. However, I do not agree that being obese is good for you. Basically self love should not be tied to physical appearance. Health is usually adversely affected by being obese (ie -a bmi of 30+ on a non athlete).

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I didn't say that the buckets of salt should be aimed towards the objective data received from experiments, simply that they should be aimed at the all studies.

Data in itself is trivial in nature. Of course water freezes at 0 C and boils at 100 C, because that is part of what defines water. Performatively though, that very point is, although objective in one manner, used rhetorically. In the same fashion, data from objective studies must be interpreted by subjects which is where salt should be aimed at.

There's no foundational truth to it. I'm no expert but most of the studies I've seen use questionable methods. Of particular concern is anything self reported. I don't know how you escape this, beyond what is already done with statistical analysis. I just don't think it's enough to trust it as anything "true".

More like, best guesses from best subjective data we could find, most of the time. Compare that to physics or biology where there's atoms, cells, laws that hold etc. Its just not in the same league, yet people seem to think it is.

Love this thread, just want to mention my general response to this is other sciences have a fundamental truth in reality that social science currently can't achieve.

Not disagreeing that all science shouldn't get salt, but I stand by saying some, like social science, deserve buckets due to their nature.

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There are plenty of studies that are replicable and plenty that don’t rely on self reporting as well

As for self reporting, yes people lie, which is why we formulate questions and interview types that lead to less lies. However some studies are by definition going to need self reporting and that self reporting is literally what makes the most sense

I’ll give you an example of what I do. I’m in the field of Social Network Analysis. We blend together various methods and fields from neuroscience, to psychology, to graph theory, and more. We try to analyze the characteristics and behaviors of social networks and it’s different types and we are able to do so using things like math. However, when we want to see who all is in someone’s social networks, we can either observe them or just ask them. So usually the first person they’ll name is their wife and maybe their kids and what not and we can work with this data. There’s little to no reason to believe they’d lie about that and studies have shown that in some regards they don’t. Hell it’s quite funny because we will get brutally honest answers on anonymous surveys were people will mention their spouse, but also the person they’re having an affair with.

The underlying driver in social networks is that of the homophily principle. To sum it up, think birds of a feather flock together. You are more likely to marry, be friends with, get along with, etc people who have similar interests and appearances to your own. This may sound like common sense but for a long time people assumed that “oppposites attract”

This principle holds true in literally every single society we have studied ever. Even primitive societies hold true to this. My favorite explanation for this is that there’s less cognitive work involved in meeting similar people and thus you’re able to move through beginning stages of a relationship much sooner. So for instance, if you were an expert in this area like I am, this whole comment would be for nothing and we could discuss finer social network theories such as Blau space or information heuristics.

SNA is the backbone behind many things such as terrorist intelligence gathering, networks, and logistics, as well as other covert Social Networks. It’s also used in neuroscience when studying social information that is stored, as well as in emergency response protocols.

TL:DR we are trained scientists just like any other. We are aware of the foundations of science, it’s limits, and societies limits, and employ tricks to get around such things. You are mistaken with self reporting as research shows people get extremely honest with anonymous surveys. I’m not mad, but there’s enough misinformation about social science as is and how rigorous it is. In cross disciplinary meetings, more often than not it’s my lab that has to remind other scientists of some of the basics, simply because we have to be the most careful out of most disciplines.

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Even if people are "honest" it's too subjective and interdependent on complex and personal dynamics that no one study will capture it properly.

I beg you to give me an example of a consistent, repeatable story that emerges from more than 2 social science studies. So far I just see you have strong opinions and love your job. That's great and all, but doesn't change my mind.

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Literally just look into the homophily principle as I stated. Maybe I should’ve mentioned that in the TL:DR. But that one has several countries and differing types of social circles it’s been studied in.

Another classic in my field is Granovetters “strength of weak ties”. It’s a classic but a little dated and was foundational for SNA. Brashears “The weakness of tie strength” modernized the theory and strengthened it. Those two studies and those related to them will cite multiple studies finding similar things.

Honestly your question is so easy to answer it leads me to believe that you’re likely parroting something some physics bro told you, but never actually looked into it yourself.

Did McDonald's sponsor this study?

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Nope.

> This research was funded by the Health Foundation. It is part of the HARVEST collaboration, supported by the Research Council of Norway. Individual co-author funding: the European Research Council, the South-Eastern Norway Regional Health Authority, the Research Council of Norway, Helse Vest, the Novo Nordisk Foundation, the University of Bergen, the South-Eastern Norway Regional Health Authority, the Trond Mohn Foundation, the Western Norway Regional Health Authority, the Norwegian Diabetes Association, the UK Medical Research Council. The Medical Research Council (MRC) and the University of Bristol support the MRC Integrative Epidemiology Unit.

Yeah. Even if there aren’t direct health effects of being morbidly obese (unlikely), the social and mood effects of not being able to participate in common childhood activities (like sports, or just regular play) seems like it would have a huge effect

Maybe the study can address the asshole kids that bully people because they are overweight.

The parents of morbidly obese children belong in prison for child abuse.

I’m a father with a child that deals with weight issues because of medications he has to take. I see the effect it has in his behaviors. Expand your research some parents like to lie to think there children don’t have problems.

Health is affected far before obesity.

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The title of the post and article are both misleading. The study was only done with 8 year olds. The authors note that their conclusions may not apply to kids in general. Older kids are more concerned with appearance, and more likely to be self conscious, or to be bullies. I also feel like very high BMIS are probably a lot rarer in younger kinds who have had less time to put on the weight, and who usually have lots of energy. So if there is a causal effect, it seems it would be the smallest at the beginning of elementary school.

The actual paper also does state that higher BMI is associated with depression. And that "We found inconsistent evidence that a child’s BMI affected their depressive and ADHD symptoms [because it could be that the mental health issues are causing the increased BMI]". And "Our results suggest that interventions designed to reduce child obesity are unlikely to make big improvements in child mental health. On the other hand, policies which target social and environmental factors linked to higher body weights, and which target poor child mental health directly, may be more beneficial."

Basically, it sounds like the study is saying "Heavier kids are more likely to be depressed. We aren't really sure whether helping lose weight will help their depression. But we do know that helping them with their depression directly has good results, and could also help them lose weight, so give that a try." Which is an interesting and helpful conclusion.

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>You are more likely to marry, be friends with, get along with, etc people who have similar interests and appearances to your own. This may sound like common sense but for a long time people assumed that “oppposites attract”

>This principle holds true in literally every single society we have studied ever. Even primitive societies hold true to this. My favorite explanation for this is that there’s less cognitive work involved in meeting similar people and thus you’re able to move through beginning stages of a relationship much sooner.

I put it down to the familiarity principle which states people tend to develop a preference for what's familiar so people will automatically feel a person is more familiar if they have features and traits they recognise in themselves.

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Until they experience bullying due to a higher BMI? I think the mood and behavioural issues are due to social reaction to the weight, not the actual physiology of the fat itself.

Learn new terms

It might be an attempt to say self control is not related to obesity. That's the stretch I can get from it that could be a topic some might want to broach and discredit.

Force them to take dietary classes 3x a week when off work until their children are within healthful weight ranges.

>Well over 90% of biology, chemistry, and physics experiments are controlled and replicatable.

This isn't the case. The replication crisis affects all fields

My point is that whoever is funding the study will generally have results that favor them.

It's awkward to then bring up the next layer; which is that the majority of people are clinically overweight and that designation already carries health issues. Easily 60-75%+ of myriad countries now.

The pushback is immense for mentioning that what many, many, many people perceive as normal is already too sedentary and overly high in bodyfat%.

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I'd say my high BMI had a very bad effect on my mood as a child.

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I have two kids - both eat roughly exactly the same. One is a physical powerhouse, lithe and acrobatic. The younger is heavier, physically denser, and has a tougher time keeping up. They’re less than a year apart, same mom and dad, and the youngest is half an inch shorter and outweighs his older brother by.. 15-20 lbs? It definitely has an effect.

Yeah my other son is also the opposite he’s 4 years younger and I have seen a complete difference in how they are treated. Also the older one has a therapist he has talked to her a lot about it all.

Even just the way my own parents treat them differently is depressing for me. Reminds me of childhood. Ugh. Now I’m gonna have to have another talk with them about this. Glad it came up, but ugh.

It’s much easier to run controls and perfectly sound experiments for hard sciences.

Social science experiments run into ethics issues fairly frequently. Doesn’t mean they shouldn’t be studied, but they do need to be interpreted differently.

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100% I always try to talk to the grandparents as I’m trying to work as a team instead of coming at them like they are doing something wrong. An argument never helps a child everyone has to be on the same page.

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You need a source. You can’t just say that. There is a reproducibility problem in every major field so you don’t even know what you’re talking about.

Rapidly pressing X to doubt.

Eh. If i gain or lose 20 lbs of muscle, i could easily swing to a bmi of underweight to obese and neither would be accurate

If you lose 20 lbs of muscle, you’ll probably lose a lot more weight. That’s a lot of muscle to lose and your doctor would be rightfully worried about you.

If you gain 20 lbs of just muscle as easily as you make it sound like it can happen, I’ll be very impressed!

I mean this is the nicest way possible with no malice or condescension (seriously) but I don’t think you understand what 20 lbs of muscle is.

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More like almost all the comments. These people are commenting in a science sub with layman's opinions. Like the article is LITERALLY there for them to read. But classic reddit

I would really call into question nutrition here which absolutely does make an impact on behaviour and leads to issues with eating and yes, sometimes weight. How you end up overweight (is it pasta or soda etc) has a massive contribution to overall health and I'll eat my shoe if behaviour isn't a part of that.

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I was a normal sized kid. When I hit middle school/puberty and had more agency in feeding myself, I became overweight. I always wondered if I was overeating to soothe an underlying anxiety issue. It makes a lot of sense to me that I likely had anxiety issues first which caused me to gain weight, not that my anxiety was caused by being overweight. Anxiety in kids wasn’t something people were looking for in the 80s.

In my 20s, I lost 80lbs and was still depressed and anxious. I was definitely treated better by peers but neither losing weight nor being treated nicely improved my mental health.

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Thank you for that!

There seems to have been a spate of extremely misleading post titles on r/science lately, makes me wish posts had to be made just with the papers title as the post.

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There was a paper recently where the title mentioned adolescents, but didn't specify that the experiment was on adolescent rodents.

I think titles would be a step in the right direction, but when there's a financial stake in flashy headlines.. it's a losing game

The fundamental truths are all based on linguistics and your definitions of the things you're measuring, and then the science of the measuring tools and strategy.

There are so many flaws in all of our rodent experimentation. Sexism in medicine, what about a foundation of basic biology built mainly on studying male rodents and then extrapolating to humans.

Even physics when you get down to it ends up being an existential debate about the nature of the universe.And the more we discover, the weirder things get.

Atoms, cells, fundamental testable rules. Other fields have those.

Was bullied relentlessly for being an overweight child, even by my own parents. Now I'm 6'5 and grew into my weight but still deal with my self-image after battling several eating disorders. Definitely feel that

Has there been a study done with fat percentage and what about BMI extremes ?

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A good number of astronomy papers are inherently unrepeatable. You can have someone else double check your math, and if you're lucky, there will be multiple observations of the same event, but, uh, to put it simply, a star only explodes once.

Or they physically can’t keep up playing with other kids. Or they have health problems. Or any number of things.

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If you're smaller than other studies and have a result that's contrary to other current research, you've got to look at other variables pretty hard. If that's the data you have, then that's the data you have, but you've gotta explain why your study is getting different results. You should be saying, BMI correlates poorly to those outcomes in XYZ situation.

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In the actual study they do exactly that.

The headline isn't doing any favors though.

Absolutely. I didn’t care I was a heavier kid, until my grandma put me in curves (old lady work out center). Then came the anxiety, hyper focus, and eating disorders. In the long run it has done more damage than good. My brother and I both thinned out as we got older (although mine was likely due to being super strict with my calories) but the damage to my teeth/esophagus from making myself puke was permanent.

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They don’t. Just tryna dunk on the “liberal” sciences is my guess tbh

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So you mean the mood and behaviour of 500 pound 8 year olds is the same as healthy weight 8 year olds?

Yep, that's a nonsense study, what it's trying to prove is just common sense.

Was big as a kid and young adult, daughter is big now. We are strong, smart, and energetic, but “ugly” to others. Bullies are the worst. Humans are not nice creatures.

Why are you booing? He's right.

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As a student that works in a research lab and is getting a degree in Sociology studies like these are what is wrong with so much science done nowadays. Absolutely zero account for human and social activity. I don’t understand why researchers try to act like humans are in a perfect controlled environment where we can solely look at number and standardised indications.

I dreaded presidential fitness week as a chubby young boy. The one pull up, the belly rolling sit-ups, the mile run where I’d get the “I’ve been shot” cramps. The creepy scoliosis exam… oh what stressful times as a kid. But, you survive and grow up.