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Obese Kids are Not Causing the Obesity Epidemic

The math is simple – of the one in five adults in most Western countries, who are now considered ‘obese’, very few of them were obese as kids or even as young adults.

In fact, most obese adults are 40 or older. And, despite the alarming increase in childhood obesity (now affecting about one in twelve kids), obesity rates in younger adults remains at about 10% or less. Indeed, the greatest increase in obesity is seen in 45-54 year old men.

These numbers alone, should tell us that most obese adults (and thus, the vast majority of obese people alive today), developed obesity as adults – not as kids!

This is not to say that excess weight in childhood is not a major predictor of excess weight in adulthood – many of my patients recall being teased and bullied about their weight 30 years ago, when they were growing up in rural Alberta, helping with chores around the farm, riding their bikes to school everyday, and playing shinny hockey on a frozen pond all winter.

But the majority of my patients did not have a weight problem till well into adulthood.

Why do I bring this up?

Simply because, I believe that better understanding, or even fully preventing, childhood obesity is unlikely to have a noticeable impact on adult obesity rates anytime soon.

The problems that lead to obesity for the vast majority of obese adults occurred during their adult years.

Their obesity was not caused by lack of phys-ed classes, poor school lunch programs, hallway vending machines, or parents too busy to cook dinners from scratch.

Their obesity was probably also not caused by too much video gaming, too much TV watching, or not playing outside till the lights came on.

Remember, the demographic group with currently the highest obesity rates (almost one in three) were kids in the 50s and 60s – an era, when a 6 oz serving of pop was considered a rare treat.

Why is any of this important?

1) Focussing all of our efforts solely on better understanding the drivers of childhood obesity and trying to prevent it likely means continuing to ignore the drivers of adult obesity, which account for the vast majority of obesity in the population.

2) Even if we successfully eliminate childhood obesity, by say, changing our kids’ lifestyles back to the lifestyles of kids back in the 1960s, we may still see obesity affecting as many people in 50 years as it does today.

3) Adults with obesity today will live another 30-40 years (or longer) – many more adults not obese today, will become obese tomorrow – this is why preventing and treating ADULT obesity must be the most important priority for any health care system.

4) While childhood obesity is certainly a risk factor for adult obesity – the main driver of childhood obesity is ADULT obesity – having just one obese parent markedly increases the risk for childhood obesity – having two obese parents is virtually a guarantee. Thus, any solution to childhood obesity must focus on the ‘root cause’ of kids’ excess weight, i.e. having obese parents – these parents need treatment.

5) As far as I can tell, the strongest ‘halo’ affect of treating adult obesity is on their kids (the most extreme examples of this come from the kids of parents who have undergone bariatric surgery). Simply stated: successfully treat the parents and you ‘automatically’ prevent obesity in the kids.

I am not implying that childhood obesity is not a concern and that improving the lifestyles of all our kids (irrespective of their shapes and sizes) should not be an important goal.

All I am saying is that we need to stop ignoring the adults if we hope to make any dent in the obesity epidemic in our lifetime.

Imagine if the obesity epidemic was due to a virus that mostly affects adults – would we just be vaccinating the kids?

Vancouver, BC


  1. If you engage children in community activities that parents can participate in (eg. pedometer challenges, neighbourhood bike rides, swimming afternoons, etc.), perhaps their parents will be drawn in? As a medical community, we have not been very successful at engaging obese adults in exercise. I think we need to teach prevention to kids and change lifestyles of families. Once adults reach mid-40’s, hopefully they’ve already established a healthy lifestyle.

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  2. I am not a medical professional but an obese adult (also obese child 50 years ago) and I agree with the commenter that getting parents active with kids is a good start. But there are some significant barriers, speaking as a atheltic person. Places like Mountain Equipment Co-op, Adidas, Lululemon, Nike, don’t sell clothing for athletic activity that is sized to fit or look half-decent on obese adults and “big and tall” shops sell poor quality sports or leisure clothing. Therefore you are left looking and feeling awful or wearing the wrong things to be successful at the sport or activity. This is especially true for women where clothes top out at XL but men can get sports clothes in XXXL.

    There also needs to be constant reminders about the ELMM bias that obese athletes and many obese adults must have unhealthy lifestyles, which is, in fact, a wrong assumption as Dr. Sharma notes about those of us who came out of the womb obese. Just ask my paediatrician.

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  3. Who wrote this? It’s full of typos and grammatical errors, and it’s not in the usual style for the blog.

    While childhood obesity is certainly a risk factor for adult obesity – the main driver of childhood obesity is ADULT obesity – having just one obese parent markedly increases the risk for childhood obesity – having two obese parents is virtually a guarantee. Thus, any solution to childhood obesity must focus on the ‘root cause’ of kids’ excess weight, i.e. having obese parents – these parents need treatment.

    I don’t even know what to say. We know that BMI is as heritable as height. This make no sense at all. Unless the “treatment” it’s referring to is going to change the adults’ genetic makeup before they have children, then it’s not addressing the root cause. This is the kind of blame-all-size-variations-on-“lifestyle” statement that makes my toes curl.

    There have always been fat people – even when food was scarce – and there always will be. You’ve noted before that the fact that the population’s average BMI has increased a bit doesn’t mean that body size is predominantly due to food intake and activity level. In fact, most variations within the population are due to heredity. Sure, parents “cause” their children to be heavier than average if they’re heavier than average – by having the genes for that type of build.

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  4. Apologies for the grammatical errors but the facts remain – most obese adults were not obese as kids – even if we fully eradicate childhood obesity (which, as you point out, will never be the case) – we will still have obese adults. As for treatments – you know, I share the view that not everyone above any given weight needs to lose some of it – yet, in many cases you still need treatment – and I DO NOT mean ELMM.

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  5. This article is confusing. First you say that excess weight in childhood is a predictor, and many of your patients recall being teased in youth. Then you say they didn’t have a “weight problem” until adulthood. I don’t know if the distinction is between “many” and “majority” or you don’t think excess weight and being teased are a “weight problem”. As I wrote in another comment, it becomes like smoking – you see the lung cancer at 45-55, but the smoking started to “look cool” at 16. Does the delay in effect mean that they’re not causally linked?

    I think of my brother, who was overweight at 16. Do you know what that takes? A healthy teenage boy, who is growing vertically, has the energy to play basketball at lunch and the time to chase girls around the high school all day, and is still being fed a balanced dinner by his mother – what kind of food habits must be in place for him to out-eat that level of activity? And, what do you predict would happen once he stops growing, gets a full-time job computer programming, drives everywhere instead of walking, plus gets full time access to fast food, restaurant meals, and eating whenever he wants? The seeds of his adult obesity were there at 16.

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  6. @RG: I agree that much of adult obesity may have its origins in childhood or perhaps even in the womb (which brings us back to the issue of adult obesity in the moms) but there are many cases (in my patients at least) who can pinpoint specific events that happened in adulthood to prompt significant weight gain. Such factors can include professional and/or social stressors, injury, pain, comorbidities, medications, all of which can exacerbate any genetic or behavioral predisposition to obesity. For e.g. I have numerous former athletes in my clinic, who never had a weight problem till they suffered an injury that ended their athletic career. All I am saying is that let’s not forget about the adults in our discussion about the obesity epidemic.

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  7. I believe obesity is having more causations beyond the energy in and out formula with the GMO food, toxins and such. One thing I was a fat kid, not supersized fat but I had a paper route, a family that really kept the food to meal time, and was on my bike hours and hours a day and still was fat. I think exercise is good, but will it solve the whole problem?

    What do you think Dr. Sharma regarding cortisol, stress and trauma triggering off a significant weight gain? The stress in this society is a different sort of one. I wrote once in an essay that higher cortisol levels and our degree of stress in this society had to be influencing the weight. Maybe its influencing the kids? [beyond the already named toxins]

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  8. Fivehundredpoundpeep, it’s interesting that you should mention stress. As a kid, doctors told my parents that I was too heavy at every single appointment as far back as I can remember. They were always surprised by the number on the scale because, for most of my childhood, I didn’t look fat at all. In pictures with my friends, I look well proportioned (almost like an androgynous adult) and muscular rather than skinny and stretched out. I was very active, and I remember that I was really strong for my age. At that point, I think that it was just a natural difference in build.

    Then my parents’ marriage started to fall apart. I won’t get into the details, but it was a horribly stressful few years that were right around puberty for me. That’s when I actually started to look fat. As an adult, I’ve stayed fat, but I still don’t look as fat as I should given my BMI. That original heavy, muscular build is still quite visible. I’ve often wondered if I would have ended up a bit lighter if it hadn’t been for that very stressful period in my childhood.

    I seem to remember reading somewhere that cortisol has an impact on weight gain. If that’s true, then constantly badgering people about their weight, stereotyping and abusing fat people, and putting them under more stress is probably counterproductive, if you’re aiming to get them to lose weight or, you know, have a reasonably happy life that they would want to extend. Well, that part should have been obvious already.

    BTW, I don’t understand why anyone would believe that forcing fat moms to diet before, or even worse, during pregnancy would produce thinner children. If anything, I’d think that it would trigger famine resistant genes, and it wouldn’t do anything to change their basic genetic makeup. I am so sick of all of this “blame the mom” crap. Children with fat fathers and thin mothers are just as likely to end up fat. I’m one of them and hell, my dad didn’t even raise me.

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  9. If you have people plot their weight history and try and link events to the time of serious weight gain, there is often a pattern. Maybe a woman gained an extra 10 pounds after each child, gained 20 pounds when a sibling died, another 10 pounds during a large move to another state. Events and stress trigger emotional/stress eating and weight gain adds up quickly, especially if you are less active. I think that scientists are just beginning to understand how stress affects the body. Your genes are your genes though and no amount of dieting will change your genes! Your better adult habits could help your children though! We tend to pass on our eating habits to our kids.

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  10. As with genes, fathers are just as capable of teaching their children eating habits as mothers are.

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  11. What about Poverty? According to HBO’s award-winning documentary, The Weight of the Nation, public health officials can reliably predict average weight by zip code and have noticed differences in average lifespan exceeding 20 years between poor neighborhoods and affluent ones just 8 miles away on the other side of town. The poor, it’s reported, have less access to nutritious food, exercise facilities or parks for safe play, sidewalks, quality schools, employment opportunities, and political influence. Addressing obesity and related healthcare costs must include addressing the widening wealth gap, poverty and other social ills.

    A recent article in The New England Journal of Medicine showed a dramatic change in the cause of death from just a century ago, with most of it from preventable conditions related to obesity (and I contend, poverty). See It includes an embedded video from HBO’s documentary, “The Weight of the Nation.”

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  12. Excellent article, Dr. Sharma. I live across the street from an elementary school in Edmonton, and the children on its playground do not look fat to me, Every weekday I am on the University of Alberta campus, and a fat young person is very rare on campus. An obese young person is so rare on campus than you can go days without seeing even one. Most of the really fat people I see are over 30.

    I was born in 1952 (making me 60 years old), and I really don’t think that most people are much fatter than they were when I was young. I think that the “obesity epidemic” now is driven by exactly the same phenomenon as it was in 1960, and that is that many people are dismayed upon entering their thirties to find that they have grown heavier and thus less attractive, so they take up dieting and vigorous exercise in an attempt to recover their youthful figures. It’s not about health. It’s about good looks. Look at the covers of health and fitness magazines. The models on the covers are physically beautiful men and women in their twenties. That’s the ideal that is being sold, and its common unattainablity among people in early middle age is the real “crisis.”

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  13. I like what you have written here. Your voice is important and needs to be heard. I would only add that the hysteria over obesity (childhood and otherwise) is in many cases, making people fatter! I hope you’ll take a look at my new book, told from a personal and clinical perspective, FATLASH! Food Police & the Fear of Thin

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