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Post No.: 0805dna


Fluffystealthkitten says:


From a population-wide epidemiological perspective, we’ve got to realise that the human gene pool hasn’t changed that much since ~40 years ago. Yet obesity rates have rose sharply in coincidence with an environment that also rose sharply in the amount of available junk food and junk food advertising being fed to people during this time. The obesity rates for cats and dogs have shot up over the past decade too! Meow.


Identical twins can even end up becoming different sizes, and noticeably physically and mentally different in many other ways. So the key difference isn’t the natural genetic but human-made environmental evolutions. And if humans made something then they can potentially un-make it.


Epigenetics plays a role, as in how the environment and your own behaviours and experiences can switch on/off the expressions of certain genes. (The ‘double helix’ shape of DNA is now understood to be an oversimplification of how the chemicals and proteins of DNA are twisted, wrapped and dynamically interacting.) Humans share many genes with other animals – and even fruit – but they’re expressed differently.


Due to epigenetics, early experiences can have lifelong impacts, hence the importance of a healthy upbringing. Being more physically active switches on genes that burn more calories and change how consumed energy is stored. Exercise reduces the amount of bloodstream lipids. A long brisk walk the night before you have a fatty breakfast, or just before any meal, will improve how you process fats – leaving less fat and cholesterol in your bloodstream after that meal. So maybe the best time to eat your dinner is right after some rigorous exercise.


Your DNA can determine how your body makes and processes cholesterol. But gene behaviour can be modified via one’s diet too – for instance, healthy levels of vitamin E can possibly help boost APOE-4 activity, which controls the transport of cholesterol out of your body.


Although the vast majority of obese people don’t have these conditions – damage to the hypothalamus, thyroid problems and other serious conditions like these, or certain medications like steroids, can contribute to a greater risk of obesity. An under-active thyroid and low levels of thyroid hormones will lead to a low metabolism and contribute to weight gain. Obesity can however cause thyroid problems too.


Hormone levels are critical when it comes to weight management. Cortisol provides the body with glucose (energy) via the process of gluconeogenesis in the liver, which can help one to fight or flee in a survival situation, like evading a tiger. But chronic stresses and constantly elevated cortisol levels about things that don’t result in using up that energy, like stresses about constant deadlines in an office job, will lead to continually elevated blood sugar levels, which can lead to putting on weight and diabetes.


Even just thinking about an imaginary stressful event will release cortisol (well a lot of stress is due to our minds over-thinking or catastrophising the worst-case scenarios that may never happen). If this is a pregnant mother then this cortisol will affect the baby in the womb too by potentially reducing the size of the baby’s brain – which means that environmental stressors can be impacting before even birth and have lasting consequences! Cortisol gets you through the short-term via the fight-or-flight response, at the expense of long-term goals like growing bones and the brain – your body isn’t going to invest resources for any long-term goals if it feels that it needs those resources now i.e. there’s no point in thinking about tomorrow if there isn’t going to even be a next minute because there’s an immediate threat to one’s existence. But this doesn’t apply to most modern day stressors, like losing one’s phone, missing the train or ‘keeping up with the Joneses’.


Hormone injections are possible to aid weight loss, but if you want to avoid the potential side-effects then you can alter your hormone levels via your diet and activity levels, as well as by reducing stress and getting enough sleep.


Past gene therapy studies include those on IGF-1 (which encourages muscle growth (in mice at least) even without exercise) and myostatin (which puts the brakes on muscle growth, thus deactivating or reducing this in the body should allow for more muscle growth). But drugs and gene therapies won’t ever mean that people will no longer need to take care of their own bodies. You could get given a Ferrari engine and parts, but if you feed it with the wrong fuel and don’t look after the mechanical components, you’ll still end up with a heap of junk. You could be born with the potential to be the cleverest person in the world, but if you don’t bother to learn anything then you won’t know anything. We are not what we’re born with as much as what we do. And being kept alive by medications isn’t necessarily the same thing as thriving with a high quality of life either.


Targeted gene therapy is a powerful way of preventing diseases in foetuses and treating diseases in those already born. But like surgery – it starts off with its aim of helping those who are unwell get better, but then eventually some people (starting with the richest) will exploit it for mere purposes of vanity and compounding their advantages. It also interferes with natural selection at the DNA level, whether one sees this as a threat or opportunity.


A note on the controversy of home DNA testing kits at present – different laboratories can come to different conclusions because we don’t yet know enough about which particular genes and combinations are the most important for many disease risks, or what they in practice mean regarding, say, how much caffeine you’re recommended to not exceed per week because your risk of hypertension and myocardial infarctions is ‘high’?


They may lead people to worry needlessly because some tests are unreliable, or people cannot comprehend statistical odds in their contexts properly (e.g. the doubling of an incredibly low risk is still very low, yet someone may get fixated on this risk rather than on the other more pertinent aspects of their health). Conversely, people may get slack with taking care of their health and attending future fluffy health screenings because the test was incomplete but showed that one was clear of any elevated risks. So people usually benefit from a trained genetic counsellor to interpret the results. The privacy of one’s DNA data is another concern too.


When people hear that something is heritable or has a genetic cause, some will erroneously think that this means that the only answer must be some kind of biological or chemical answer like a pill, or it’s fated. But behaviour change can be an answer too. People with DNA that influences skin paleness have a say in whether they avoid melanomas by being careful in the sun. What hair colour you’re born with is down to your DNA, yet you could dye it. A strong cardiovascular system will reduce or delay your chances of developing dementia. (Be aware that the onset of dementia doesn’t just happen at over 60 so it’s best to maintain a strong cardiovascular system as early as possible in life. Well exercise seems to be far less effective, or even totally ineffective, when dementia has already set in; although more research is needed in exploring the efficacy of different types of exercise.)


Where and how we’re raised shapes our beliefs and habits. If we were born into a religious household in a religious country then we’d highly likely be religious too, with all the cultural traditions that entails. If we were born into a healthy-eating and active household then we’d highly likely have healthy habits too. Our parents, siblings, peers, teachers, role models, the media, government and everyone else around us influence us, and we influence them.


Our upbringing and lifestyle can change the capacity and number of our fat cells; making it harder to lose fat and easier to put it on later in life. Hence why it’s best to prevent an individual from ever becoming obese in the first place i.e. we need to instil healthy living habits when young. Fat cells increase in size then in quantity – but (in non-human animal studies at least) fat cell quantity doesn’t decrease until possibly an extremely long time. It’s therefore relatively easier to become obese again once one has become obese before, because the number of fat cells in the body remain for a very long time even after one has lost lots of weight.


Life events and environmental changes can mean that someone, despite being thin when a child, can become obese when an adult, or vice-versa. But how one is raised shapes the probability of how one will continue as an adult. It’s just like not everyone who wears a seatbelt survives car crashes but it raises the probability and thus it’s still sensible to wear one. We shouldn’t abandon something that works for most cases just because it doesn’t in a relatively few cases. The headlines, and our own confirmation biases, have a tendency to focus on the tree that stands apart rather than the whole forest, but we shouldn’t be focused on less common statistics whilst ignoring the bigger truths.


We can reduce the non-communicable diseases (diseases that aren’t directly transmissible from one person to another) attributed to obesity by improving the physical, social, cultural and economic dimensions of the environment to be more conducive for healthy lifestyles instead of the opposite. Prevent the obesity-related diseases in the first place. This is better than relying on the healthcare system to treat diseases once they occur. In fact, if it weren’t for modern medicine in treating obesity-related diseases (which is often publicly funded), the obesity crisis that’s in key part contributed by the proliferation of junk food (which mostly feeds private profits) would be far worse.


But some of us don’t want the government to nanny us. Yet when things go wrong, they’ll inculpate the free market for causing them harm and/or the government for not stepping in(!) If you try to help, you’re patronising. But if you don’t, you get blamed!


Global food shortages could become more prevalent due to climate change and wars – but is this the natural ‘self-correction’ to the obesity crisis we really want?! Well this probably won’t solve it anyway but merely further widen the gap between the obese and the starving in the world.


…All in all in our investigation into ‘obesogenic’ genes and environments, which started in Post No.: 0794, we cannot just blame our parents for our DNA. Genes, no matter how ‘good’ or ‘bad’ you think yours are, are overall only about half the story, thus even if you could completely change your own DNA to whatever you wanted – your environment still plays a major contribution to your outcomes. For instance, in an environment with no soft drinks – no soft drinks would logically be consumed regardless of if you possessed many genes that increased your penchant for them! It’s both nature and nurture.


We cannot just blame our parents for our upbringings either. The wider environment is influential on them too, as well as us. And we cannot completely control our own environment all of the time (e.g. the prevalence of fast food restaurants near where one works).


It can evidently be harder for some than others to maintain a healthy weight in the modern environments that many of us now live in – yet there’s still enough control for nearly all of us to live healthily unless we live in severe poverty. We can ultimately control what we stick into our mouths for dinner. We shouldn’t think like we’re mere passengers in life.


Meow. Also, your Land Rover may not be a Ferrari, but you can still get from A to B quite well; and you’d be more capable if you ever needed to go off-road too.


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