Big Fat Lies!

a 5-minute read

Have you heard people say that being overweight is a choice? Or that it’s just about calories in versus calories out? Well, misinformed statements like this are often said by those with little understanding or recognition of the complex and multifactorial nature of obesity and are just… big fat lies!

As someone who has struggled with my own weight from a young age and who was bullied for being the ‘fat kid’, I’ve had a personal interest in weight management for as long as I can remember. In fact, I think it’s one of the reasons why I entered healthcare and why I’m such a strong advocate for exercise, having found it to be the best way to control my own weight after trying and failing many other methods.

Me at 16 years old, and nearly 16 stone… and no that cake didn’t stand a chance

Although exercise has, and still does help me manage my own weight I know it’s not the answer for everyone, and I have slowly come to understand that weight management is a complex and complicated topic that goes far beyond just exercise and calories. Unfortunately, many healthcare and fitness professionals have not and many still believe that being overweight is a simple condition brought on by choosing to eat too much and exercise too little.

Calories In / Calories Out

This is bullshit, in fact, if I hear another fitness professional say ‘calories in v’s calories out’ without any context I think I will drop kick them in their fart box, because although in principle this sounds accurate and simple, it’s just not this simple or accurate. The causes of weight gain and obesity are in fact far more complex than just ‘calories in calories out’ involving physiology, psychology, and sociology.

Saying obesity is as simple as calories in versus calories out is no different than saying poverty is as simple as money in versus money out, or depression is simply happiness in versus sadness out! I think we can all agree that no-one chooses to be depressed or poor so why is it any different for obesity?

In the late 1990s, obesity was classed by the World Health Organisation as a global pandemic due to the direct links it has to increases in many other diseases such as diabetes, hypertension, cardiovascular disease, osteoarthritis, some forms of cancer, and mental health issues such as depression (ref).

There is still much debate around if obesity should be considered a ‘disease’. But when you consider a disease is defined as…

  • A condition that impairs function and reduces life expectancy
  • A condition that leaves an individual more susceptible to other diseases
  • A genetic impairment that leads to other functional impairment

Obesity checks all of these, even the last one! Yes obesity is a genetic impairment. There is now some strong evidence that shows obesity is dictated a lot by genetic factors as demonstrated in multiple identical twin studies, done in multiple countries, on various different aged individuals (ref).

It is also known that genetic variations can increase an individuals propensity to obesity such as leptin and POM-C receptor deficiencies (ref, ref). Our genes play an important role in how we all respond differently to the foods we eat, the number of calories we consume, and the environments we consume them in.

For example, have you ever wondered why two people who eating the same types and amounts of food often have completely different weights and body fat percentages? Well an interesting study conducted on 12 pairs of identical twins closely monitored the affects of overfeeding them by 1000 calories a day, everyday, for 100 days, and found weight gains were very similar for each twin, but varied hugely between the pairs of twins from 4kg to 13kg (ref).

This clearly shows how genetics has a role in determining how much weight is gained based on the calories consumed. There have also been a number of studies that looked into the effects of genetics on weight gain in rats to try and see if they could find any more answers.

Fat Rats

In one study 100 rats were all fed the same high-calorie diet for a few months. Again they got a lot of variation in amounts of weight gained by the rats, with a bell shape curve with a few of the rats not putting on any weight at all, a few rats putting on huge amounts of weight, and most of the other rats falling somewhere in between (ref).

Now the interesting part with this study is they then took the rats from this trial who didn’t put on any weight and bred them together, as well as taking the rats who put on the most weight in the trial and bred them together. And after a few rounds of breeding these different weight gaining rats they got two very different types of rat.

In the first group of rats they got offspring who were very diet-resistant, that is rats whose weight did NOT increase when they over-consumed calories. However, in the other group of rats they got obesity-prone offspring who gained weight very quickly and very easily with overconsumption of calories.

What’s also interesting is that if you take these obesity-prone rats and place them on a low-calorie diet they lost weight, but as soon as their calories were returned back to normal baseline amount their weight quickly returned back to their starting obese weight, even though they were not over consuming calories. Meaning you can get an obese prone rat to lose weight, but unless you keep it on low calories forever its inherent nature is to be an obese rat.

The same thing most likely applies to humans. If you were to take a thousand children and weigh them, their weight will also be distributed in a bell-shaped curve. Some skinny kids, some kids in the middle, and some overweight kids. Some of the skinny kids will remain skinny throughout their life, and some of the obese kids will stay obese throughout life, meaning you could argue that their weight, to some degree, is predetermined.

Now, of course, it’s not just this simple as humans have had the same genes for 100’s if not 1000’s of years, and it’s only recently that obesity has become a bigger problem, so how do we explain this? Well, the obvious answer is the sudden increase in the easy access to very calorie-rich food.

It is now extremely easy to eat your entire daily quota of calories in a single meal that doesn’t cost much and doesn’t leave you satisfied for long. High-calorific meals full of calories dense corn starches and sugars, not to mention sugary drinks and alcohol that can contain 100’s if not 1000’s of calories without providing much satiety mean we over-consume really easily.

Although our genes play a big role in our weight, our environment also plays a huge role too. The readily available abundance of calories in many modern lifestyles is a relatively ‘new thing’ in human evolution, and it appears our genes haven’t quite managed to adapt and it’s not certain if they ever will.

In our history, genetic selection has prepared and equipped us much better for famine rather than feast, and for good reason. Food used to be scarce and infrequent, and periods of starvation were common throughout human history. Obviously, this was difficult and unpleasant to deal with, but is the opposite scenario we now face any better?

So if obesity is a disease the question we need to ask, just like we would for any other disease, is how can we prevent, treat, or even cure it? Well just like any complex disease there will not be any one single simple quick fix or solution. However, one interesting area that could hold a lot of potential is how our neurophysiology can affect our behaviour.

Fat Hormones?

A neurotransmitter called GLP-1 has been shown to affect nerve cells that control whether we feel full or not, and so dictate if we eat or not, and GLP-1 has been found in both our brains and our guts literally allowing them to ‘speak’ to each other (ref). Research has shown that if you increase levels of GLP-1 your desire to eat is significantly reduced and even halted, acting a bit like the full signal on your cars fuel tank and although more work is needed there are some promising results here (ref)

Of course, GLP-1 or any one neurotransmitter in isolation is not the whole answer to obesity and there are numerous other avenues of research into physiology, psychology, and behaviour change needed, not to mention a huge shift in governmental and societal approaches and beliefs to food and weight management. However, research like this does give us some insight into the complexity of obesity and some hope that there are solutions for this growing pandemic.

Moving forward we all have to recognise that if anyone wants to loose some weight they often have to change their behaviour but also their environment to do this, which isn’t always easy or possible to do. However, if we want to change a populations weight then its essential that we all change the environment so that it is suitable and conducive to weight lose for everyone, and not just for those in privilege!

Lose some weight, lose some pain

Personally I think a lot more healthcare and fitness professionals need to be much better educated into the complexity of obesity, and far better educated and equipped to help and support those with it. A recent paper has highlighted how obesity is highly prevalent in chronic pain populations, and as a physio, I have found helping some people lose some weight can be a great way to help them lose some pain (ref).

Not only does losing weight decrease some of the physical and mechanical loads on our bodies which may be sensitive or irritated, but it can also, and probably more so, help to lower systematic inflammation levels and improve a host of other metabolic and neuroimmune functions.

More importantly, I think helping someone in chronic pain lose some weight by helping them find some strategies that work for them in their current situation, can help improve their confidence and self-efficacy which can in turn, help them gain control and ownership over many other aspects of their lives which may help mediate their pain.

Again, I am not going to say this is simple or easy to do, but from my own personal experience I know how much better I felt once I gained control over my own weight, and I think many others will do too.

As always, thanks for reading





  1. Yes I can understand this but not why it is so different over generations. Is it fast food, little interest in cooking less exercise ( people used to walk!)
    Any ideas?

  2. Thanks for a very thought provoking article Adam. I don’t always agree with everything you say, and how boring a world it would be if we all agreed on everything! But your articles always cause me to reflect and question my values on the issues you discuss, and that can only be a good thing.

  3. Interesting. Are you awere of the work of Prof Tim Spector? He’s made the largest twin study of all time. Identical jeans, different weights. He’s a Microbiome advocate, which may or may not be your bag.

  4. As an avid listener to the NAF podcast I have digested a lot of valuable content from you over the years. However, the most recent extrasode and blog is, quite frankly, harmful (Ironic considering your recent BS series on instagram) to society. It is proof why physios should stay in their lane and avoid diverging into topics they know little about. To suggest health professionals saying calories in/calories out are doing a disservice is downright hypocritical. Overweight people don’t need ay more excuses for why theory are overweight and this is exactly what you’re doing by giving them outs for their fatness. Physio is all shades of gray weight loss really isn’t as much as you try to say it is.

    Let’s point out an obvious logical fallacy:
    False equivalence – The money in/money out example. Money is something people do not have full control over, whereas everyone has absolute control over what goes in their mouths. If a poor person was given 1 million dollars a year from some hypothetical benefactor they would no longer be poor so it would be correct to say money in/money out. We both know how stupid it would be to believe such a fairy-tell to ever happen. With food, every calorie is consumed by us through our mouth, we purchase the food and it goes in the stomach and absorbed into the system. Eat less of said food means less calories in, AND if it’s below maintenance calories you lose weight. There is no equivalence there to money.

    The rat study you cite, your message isn’t disproving calories in/out at all, in fact it’s the opposite. You seem not to understand the set point & homeostasis and how they influence weight loss. The genetically disadvantaged fat rats have their set point still up near their original starting weight. It makes absolute sense why the rat’s body will quickly try to return to homeostasis and prioritize that through bodily processes aiding fat gain. This is evolutionary, potential feast/famine. As you state, their calories were “returned to normal” after the Low-calorie diet. Returned to normal is now a calorie SURPLUS for them, their maintenance dose of calories needed to DECREASE to maintain weight loss.

    This is the same in humans, your calories must change as you change weight as the leaner you are the lower your metabolism, your NEAT (Non-exercise Activity Thermogenesis) decreases. If someone has terrible genetics, it sucks to be them but they just have to eat less. You don’t get to eat the same as your friends who have a higher metabolism or burn more calories or have a higher NEAT. If that person follows those friends you will be fat because you are in a calorie surplus they are not. There are no ifs or buts, IT IS WHAT IT IS. the uncomfortable truth that fat people don’t want to hear. AND they then cry that “I don’t eat THAT MUCH. If you are putting on weight you are in surplus.

    Every starvation study done in humans has shown weight loss. No matter their genetics , A calorie deficit leads to weight loss…. PERIOD. A calorie surplus leads to weight gain….. PEROID.
    You lost weight Adam because you were in a calorie deficit…..Period

    The ultimate science, the laws of the universe, of thermodynamics. “Energy cannot be created or destroyed”. No human being in existence can overcome the law of conservation of energy. If they could, there should be some fat, starving third-world children somewhere. I have yet to see a fat starving child but if you find one please enlighten me, then we can end world hunger forever.

    Genes play a role in our weight – They do and they impact what each person’s set point, metabolism, NEAT is going to be but again it’s calories in/calories out. To power a human body still requires a minimum number of calories per day. So it doesn’t matter what excuses someone wants to use whether it’s hypothyroidism, Leptin sensitivity etc. the answer is just eat less. IF YOU ARE NOT LOSING WEIGHT YOU ARE NOT IN A CALORIE DEFICIT. The remedy?…………Eat less.

    2 friends live together- Friend 1 cries that they both eat the same but they are getting fatter

    Friend 1 is 80kg has a metabolism of 1800, NEAT of 200 and fairly active job burning 300 a day. Their maintenance is 2300.

    Friend 2 is 80kg has a metabolism of 1800, NEAT of 100 and is sedentary . Theiri maintenance is 1900.
    They both eat 2100 a day on average. Person 1 will lose weight and person 2 will gain weight.

    The biggest barrier to weight loss is always wIllpower. I am a great example of this. Was not a shredded kid, was average. I started at 22% body fat @ 95kg after a bulk and cut down to 8% bodyfat shredded @82kg. My secret to get below 12%, GLP-1 agonist Semaglutide/ozempic. Previously, I didn’t have the willpower to get below 12%, I knew what I had to do but food was too tempting, eating out with friends, alcohol it was too fucking diffciult. The leaner you get the more Ghrelin punches you in the face…….. Until Ozempic/Semaglutide took away the appetite and I could adhere to the plan. I kept in my deficit, ate 1500 calories a day on average as a 85kg bodybuilder and eventually got there. The drug doesn’t affect anything other than appetite. It allowed me to stay in a calorie deficit by taking away willpower as a variable. I could have out-eaten the drug if I purposely tried to.

    Change is uncomfortable, the body likes homeostasis and fights you every step of the away as soon as you move away from homeostasis.

    Whatever variables you pick that factor into obesity it comes back to Calories in calories out every time. E.g:
    Socioeconomic status – If your socioeconomic status means you can’t afford good food…….. Simple, don’t buy as much food. Bonus, You save money too!!!!!

    For those that are obese, to quote Greg Doucette (someone people should be listening to for weight loss advice) – “Put the fork down”

    I would recommend watching Greg Doucette, I thought you would be the type to watch him already but alas.

    Also secret eaters (makers of embarrassing bodies, homegrown UK programming for you) is a great show to show how delusional the general pop. can be in regards to their food intake & caloric balance.

    • Wow… that’s quite the rant there Matthew, and a lot of harsh, unfair accusations about me being harmful, not to mention some horrible people blaming and other bullshit. I did think to just ignore you and this rant but thought I would reply as you seem to be completely misunderstanding and misrepresenting what the blog is trying to get across, and so I will try to put this as succinctly and politely as I can.

      You have completely missed and misunderstood the premise of the post. I don’t state it’s NOT about calories in / out… I state it’s not as simple as, or only about calories in / out. If you cant and dont appreciate and recognise the social, economical, environmental, psychological, behavioural, and genetic issues that all contribute to obesity and weight management then I think you shouldn’t have any role in trying to help others manage their weight.

      Your self-indulgent, delusional, personal experiences of how you lost weight count for nothing except to you. To think everyone can and should lose weight just like you have, or I have, or anyone else has done is both ignorant arrogant and pathetic, and clearly shows you have little understanding of the complex and multifactorial causes of obesity or weight management, its not only about will power… at all!!!

      Also if you are that naive and insensitive enough to state that “overweight people dont need any more excuses”, then again you shouldn’t be working with, or be responsible for others’ weight management, and I would ask you to stop blaming people, and to read a bit more about social determinants of health here to start.

      • You probably won’t reply to this because you hadn’t even bothered to reply to the important parts of my argument that were disproving everything you tried to pass off as fact.
        First I want to commend you on your weight loss, it requires incredible effort and willpower to achieve the weight loss you did. Well done, hats off to you!
        THat being said, You are literally arguing against the law of thermodynamics. I look at you right as you might a flat earther, arguing against a law of the universe with “studies”
        “I don’t state it’s NOT about calories in / out”. You state “calories in/calories out is bullshit”. What does that mean to you? Or, more importantly, what do you think that might mean to a reader? You can be all technical that you didn’t literally “state it” but you know if you call something bullshit what that connotes to any normal person.
        All those factors you stated (social, economical, environmental, psychological, behavioural) are BEHOLDEN to calories in/out. Doesn’t matter what factor you want to pick that impacts on obesity, EVERYTHING comes back to calories in vs out. If you have shit genetics and your Basal metabolic rate is lower than your mates, sucks to be you but the answer is eat less. If you’re environment means you only have bad food options? Eat less of that food.If you’re friends are big social drinkers and eaters? Eat or drink less.
        My story was not to highlight ‘how good I am’, it was to highlight that I, a physio & bodybuilder with in depth weight loss knowledge, still couldn’t get to my goal without the help of an illegal drug (Semaglutide). By using my story I am highlighting that weight loss is extremely fucking hard even though the answer is simple (eat less & calorie deficit)
        I think you are biased because you used to be fat and still have holdovers from those emotions when people would call you on your fatness. Now, I’m pretty sure you’ve mentioned hating snowflakes but this is exactly what you’re being. It’s funny you call me delusional yet that is exactly what you’re being. Explain how I was delusional? The truh ins’t nice, Fat people are looking for reasons to explain their fatness that are out of their control. That is why I say they don’t need any more excuses, they are instrincitnely looking for excuses .
        Social determinants of health?? Health and weight loss are not the same thing. I can eat one big mac every day and someone else can be eating the cleanest, most healthy diet of 3000 calories a day. The person eating the big mac will lose significant weight and the person eating healthy will be putting on fat

  5. Hey Adam, sent you an email as I didn’t want to write an essay here. Loved the episode and would love to hear your thoughts!

  6. A really interesting episode. Thank you.I need to confess you used to really trigger me but the more I look past the social media headline and listen to what you actually have to say I am learning so much.

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