It’s a common pastime among Gen Xers like me, and Baby Boomers like my husband, to reflect on the number of ‘fat kids’ we knew when we were at school.
Overweight and obese children were such a rarity in the 1960s and 70s that the handful we encountered really stand out in our memory; I shudder to think about how they must have been impacted by their unwanted notoriety.
And in retrospect, the handful of ‘fat kids’ whom I recall were mostly in the mildly plump category, and would probably not be singled out by today’s children – not necessarily because Gen Z kids are more tolerant, but because being overweight or obese is now normal.
The Australian Institute of Health and Welfare (AIHW) began collecting data on childhood overweight and obesity in 1995. These AIHW data confirm, quite literally in graphic detail, that Australian kids are growing steadily fatter:
“At ages 10–13 and 14–17, children and adolescents born most recently were significantly more likely to be overweight or obese than those born 20 years earlier. At age 10–13, 31% of children and adolescents born from 2002–2005 were overweight or obese compared with 24% of those born from 1982–1985. At age 14–17, 30% of adolescents born from 1998–2001 were overweight or obese compared with 19% of adolescents born from 1978–1981.” (AIHW, ‘Overweight and obesity: an interactive insight’.)
Most concerningly, while the proportion of kids in the ‘overweight’ category dropped in 2017-18, that drop was not due to more kids attaining normal weight, but to more kids moving from the ‘overweight’ to the ‘obese’ category.
But is this really a problem? Shouldn’t we just change the culture to shut down ‘body shaming’ and promote ‘fat acceptance’? I’ve made the case against this approach in a previous article, Is the ‘Health At Every Size’ movement helping or hurting?, so I won’t rehash those arguments here.
The unpalatable truth is that excessive body fatness is harmful at every stage of the life cycle, and its negative effects are intergenerational – that is, being overweight before and during pregnancy inflicts harms on babies that may persist throughout their whole lives and even their own children’s… and prospective dads aren’t off the hook either.
Consider these recent studies:
- The epigenomes of children whose fathers were overweight at the time they were conceived showed substantial alterations in genes that influence the development of brown adipose tissue (which ‘burns off’ excess calories as waste heat), bones and kidneys, affect appetite regulation, and increase the risk of mammary and germ cell tumours. These epigenomic alterations were still evident when the children were followed up at ages 3 and 7, suggesting that being a fat dad may harm your children’s long-term health and condemn them to battling with their own weight. See Association of Periconception Paternal Body Mass Index With Persistent Changes in DNA Methylation of Offspring in Childhood.
- The sons of women who were overweight or obese before they conceived had impaired psychomotor development (i.e. reduced co-ordination between their brains and bodies, which affects movement, coordination, manipulation, dexterity, grace, strength and speed) at age 3, compared to sons of normal-weight women. See Prepregnancy obesity is associated with lower psychomotor development scores in boys at age 3 in a low-income, minority birth cohort.
- In separately-published findings from the same study, sons of women who were overweight or obese before pregnancy had a substantially reduced IQ when tested at age 7, with specific impairments in scores for perceptual reasoning, processing speed and verbal comprehension. Since childhood IQ is a potent predictor of education level, socioeconomic status and professional success later in life, women who conceive while overfat may be compromising their sons’ potential for the rest of their live. See Prepregnancy obesity is associated with cognitive outcomes in boys in a low-income, multiethnic birth cohort.
- MRI scans comparing the brains of obese children to those of normal-weight kids found that obese children had a significantly thinner cerebral cortex, particularly in the prefrontal cortex, which is a brain region that mediates executive function (our working memory, and ability to exert self-control, focus on particular tasks and handle our emotions). The relationship between cortical thinning and obesity is somewhat chicken-and-egg: it is not clear whether having a thinner cortex causes children to make poorer dietary choices which lead to obesity, or whether the low-grade inflammation induced by obesity causes damage to the brain, resulting in cortical thinning. Animal studies suggest the latter. In either case, the process is likely to be self-perpetuating – that is, poor dietary choices will exacerbate the cortical thinning, further undermining self-control and driving even poorer dietary choices. See Associations Among Body Mass Index, Cortical Thickness, and Executive Function in Children.
- In separate studies by a Brazilian research team, MRI scans of the brains of obese teenagers found disrupted connectivity in areas of the brain involved in appetite regulation, impulse control, emotions and reward and pleasure in eating; and inflammation-related damage in brain regions related to emotional control and the reward circuit. This damage was correlated with changes in levels of the hormones insulin and leptin, which play crucial roles in appetite regulation and fat storage. As with the above-mentioned MRI study of obese children’s brains, these two studies point to a vicious circle in which obesity-related brain changes drive behaviour that perpetuates obesity.
Taken together, the results of these studies paint a picture of obesity as an intergenerational “sexually transmitted disease”: overfat individuals have babies whose brains and epigenomes are altered in ways that make them more likely to become overfat children who grow into overfat teens who grow into overfat adults who go on to have overfat babies.
And the AIHW data indicate that with each repetition of the cycle, individuals are getting fatter and fatter.
What is to be done about this vicious circle? Clearly, we live in an obesigenic environment, in which it’s easier, cheaper and more convenient to obtain energy-dense, fat- and sugar-laden, ultraprocessed and hyperpalatable food than health-promoting food, while the requirement for physical activity in everyday life has dropped precipitously.
This obesigenic environment has insidiously spread throughout the developed and developing worlds; to date, no country has been successful in turning back the tide of obesity.
To address the obesigenic environment would require a massive co-ordinated effort, along the lines of the only major public health success of the latter half of the twentieth century: the reduction of cigarette smoking. This was achieved through a suite of legislative changes (banning smoking in workplaces and public spaces), litigation against tobacco companies, financial disincentives (tobacco excise and cigarette pricing strategies), constraints on cigarette marketing (banning cigarette advertising and sponsorship deals, plain paper packaging), and social marketing and public education campaigns (warning labels on cigarette packets, media advertising on the harms of smoking and promotion of smoking cessation programs).
As a result of this coordinated approach to tobacco control, rates of regular smoking dropped from 72% of males and 26% of females in 1945, to 16% of males and 12% of females in 2018.
Unfortunately, successive governments – especially those on the right of the political spectrum – have demonstrated great reluctance to apply the strategies that proved successful in tobacco control to the obesity problem.
Consequently, at this point in time it’s up to individuals to get informed about the risks to themselves and their children (including future children) of being or becoming obese, and to adopt healthy diet and lifestyle habits that will allow them to lose weight in a healthy and sustainable way.
It’s particularly critical for both men and women who want to start a family, to get themselves into good health – including healthy body composition – before they conceive.
And parents with overweight children or teens have a duty to help their kids attain normal weight, not through ‘dieting’ but through a whole-of-family approach to healthy eating and regular physical activity.
Gaining a solid understanding of caloric density is critical – read my article Caloric density – the key to weight-loss success! for a brief introduction – and is always my starting point when I’m counselling clients on weight loss.
Meal timing strategies (see Which meal should you skip for weight loss?) can be used to accelerate weight loss in people with long-term obesity, and optimising sleep (see Sleep yourself slim and healthy) and physical activity offer additional benefits.
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