The Real Reason Mankind is Getting Fatter

Everyone has an opinion regarding why the human race has steadily been getting fatter since the first half of the 20th century. There’s the “too much sugar” lobby, the “excess saturated fat” campaign, the “gluten is killing us all” group and many more that defend the idea that the obesity epidemic is caused by high-fructose corn syrup, food additives, modern agricultural products, dairy, carbs, eating at night, hydrogenated vegetable oil, emigrants, Obama... you name it, you’ll probably find a movement that claims that one single food type is responsible for humanity’s expanding waistline and declining health.


Why the focus on a single particular food or food group? It’s simple really; people like to be able to put the blame on something definite. If you say that “X” is making everybody fat and unhealthy, then all you need to do is eliminate “X” and you’ll lose weight and get healthy again; Get six-pack abs in six weeks with the “No X Diet”, that’s how you sell a successful fad-diet. Remember the “No X Diet” folks, we’ll talk about it a little later.


But can the obesity epidemic really be blamed on a single food-type in our modern diets. The best thing to do (and my duty as a scientist) is to look at the data. A lot of the information that I’m about to give here is from the United States because

A: Lots of Americans are fat and

B: They’ve kept pretty good records of it.


Let’s first see what the problem actually is;  the National Health and Nutrition Examination Survey (NHANES) run by the Center for Disease Control (CDC) revealed that 

  • 13% of adults in the U.S. were classified as obese in the Early 1960’s
  • that number rose to 15% in the early 1970’s
  • 16% at the beginning of the 1980’s
  • 23% in the early 1990’s
  • 31% by the year 2000
  • and a hefty (pun intended) 36% according to the most recent set of data in 2014 {1,2}.

Now bear in mind that those figures are just for obesity i.e. people with a Body Mass Index (BMI) over 30. If you include the overweight individuals too, you get a scale-tipping 69% of the U.S. population with a BMI of over 25 (while I’m not a fan of BMI as an indicator of overweight, it does serve its purpose in population statistics) {3}.


So, we’ve confirmed what the problem is; America is after getting REALLY Fat.


“Well, we already knew that” I hear you mumble. Good for you, I just needed to make sure you were paying attention. Now, let’s take a look at why this happened.


According to the data from NHANES the average calorie consumption for U.S. adults in the early seventies was 1971 kcal/day. This steadily rose during the seventies, eighties and nineties until in 2004 it had reached an all time high of 2267 kcal/day; a rise of almost 300 calories a day. Luckily that number has actually gone down since 2004 and daily caloric consumption in the U.S. stood at 2172 kcal/day as of 2010 {4}, which is still 200 kcal/day higher than the figures from the seventies. Now, before we go any further it’s worth pointing out that the data used here came from dietary recalls which are notoriously inaccurate as people tend to under-report foods they consider bad and over-report foods they consider good. However, once again for the purpose of observing trends over time, they do a decent job as you can observe that the “under-reported numbers” are increasing.


Now, while 200 extra calories a day might not sound like a whole lot I can assure you that over a long enough time period that much of a calorie boost will help get you well on your way to getting a new spare tire. We can even take a look at where those extra calories are coming from to give us a better idea of what people are eating more of. Between the 1950’s and the new millennium:

  • meat consumption increased from 63 kg/person/year to 89kg/person/year
  • total dairy consumption actually dropped by 50kg/person/year but cheese consumption increased by 10 kg/person/year
  • added fats and oils increased by 14 kg/person/year (mostly from salad and cooking oils)
  • total grain consumption increased by 20 kg/person/year
  • consumption of all caloric sweeteners (sugar, high-fructose corn syrup etc.) increased by 19 kg/person/year {5}.

So to answer that question of what exactly Americans have been eating extra of to get so fat,  the answer would appear to be... EVERYTHING! Admittedly the majority of those extra calories are coming from refined carbohydrates, especially sugars {6,7} but in general, consumption of many major calorie sources in the U.S. has increased dramatically in the last half century.



Excess food, junk food, obesity epidemic
Since about the second half of the 20th Century, people have just been eating too much... of everything (except fresh fruit and veg).



So, is that it? Are Americans just eating too much (of everything) or is anything else playing a role here. Well, let’s take a look at the other side of this increasingly rotund coin. You get fat when you take in more calories than you burn during physical activity and just being alive. While being alive is a pretty constant activity, levels of physical activity can and do vary a lot. Between 1950 and 2000:

  • the number of people working in low physical activity jobs increased relatively by 83% whereas...
  • the number of people working in high physical activity jobs decreased relatively by 25% {8}.

Looking at it another way, American men and women today are burning, respectively, 140 and 124 LESS calories than in the 1960’s{9}. On top of that, from the 1950’s to 2000, the distance traveled in vehicles (i.e. sitting down for extended periods of time) increased relatively by a staggering 224% and daily hours watching television increased by 61% showing that sitting down has quickly become one of America’s favorite pastimes {8}.


Now, let’s try and analyze this data in the simplest way possible, after all Occam’s Razor dictates that “The simplest explanation is usually the correct one”. We’ve seen that in the past 50 or so years, energy consumption has increased by about 200 calories/day and energy expenditure (physical activity) has decreased by well over 100 calories/day meaning that Americans now have an energy surplus of over 300 calories/day. The first rule of thermodynamics states that “Energy can neither be created nor destroyed, but transformed from one form to another”, so what is all that excess energy transformed into? That’s right; love-handles, man boobs, beer bellies, thunder thighs and whatever other cute nickname you can come up with for excess body-fat. To be even more specific, based on the assumption that 1kg of body fat contains about 7000 calories {10}, with a calorie surplus of 300 calories a day someone could “theoretically” gain 1kg (2 lbs.) of body fat in just 23 days or nearly 16kgs of body fat in a year. Thankfully this doesn’t happen as the human body can increase energy expenditure a little over time to counter the excess calories, but only to a certain point.


The disappointing truth of the obesity epidemic

So the answer to the great question of why the world is getting so fat is disappointingly simple; “People are simply eating too much and exercising too little”.


Why do I say, “disappointingly”? Well, taking this information into account, people no longer have a single scapegoat to blame their weight-gain on. According to the evidence I’ve shown here you can’t simply say that you can no longer fit into your skinny jeans because of all the gluten that people eat nowadays or because High-Fructose Corn Syrup has messed up our metabolisms or because human beings weren’t designed to eat modern agricultural products like grains and dairy.


The simple fact of the matter is that nowadays, people are too lazy and too greedy... and nobody wants to hear that about themselves.


That’s why it’s such an unpopular concept and that’s why there has been a surge in fad diets promising weight-loss by cutting out entire food groups while allowing you to eat as much as you want of others.


Now, I can already hear many of you screaming that you or a friend of yours lost a load of weight by going on a gluten-free diet or by going low-carb or Paleo or Raw-Vegan. I have no doubt in my mind that you or someone you know, did just that. The truth is that these diets do actually work but not because you’re eliminating something that your body isn’t adapted to consuming. These diets work for one simple reason... you end up consuming less calories.


Like I mentioned at the start of this article, all of these “No X Diets” try to convince you that you need to eliminate some specific foods (X) from your diet. What happens next is virtually identical in all of these diets;


You end up eating far less processed/ready made foods (or none at all) and you start cooking at home a lot more. The simple combination of not having as many options of possible foods to eat (people eat more with greater food choice) {11} along with being more conscientious about the food and portions that you consume means that overall you just take in less calories. And that’s it! The “secret” of all these fad diets is simply reducing calories. There’s no magic to any of them, just basic thermodynamics.


Well, if losing weight is so simple, then why is the world still getting fatter? I’ve shown that the whole weight loss equation is simple but unfortunately human nature means that it’s not easy. People will literally try anything to avoid eating less and exercising more. Why do you think liposuction and “diet pills” are so popular these days? People generally don’t want to make changes to their lifestyles and if they do, they want to do it following the latest, sexy diet fad.


My whole intention with this article is simple; to educate. The world of nutrition is filled with a lot of misconceptions and downright lies (albeit I’m willing to admit that some of them might be well intentioned lies). The general population deserves to know the actual mechanisms behind the current obesity epidemic and they also deserve to know what they can do to counter it for themselves. At the end of the day there are multitudes of diets and countless ways that will help you lose weight. I honestly don’t care what way a person achieves their weight-loss as long as it’s both healthy and sustainable in the long term. Achieving that is another article in itself.


Eat well folks.


Have you been working out? You're looking good!
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  1. Flegal KM CM. Prevalence and trends in obesity among us adults, 1999-2000. JAMA J Am Med Assoc. 2002;288(14):1723–7.
  2. Ogden CL, Carroll MD, Fryar CD, Flegal KM. Prevalence of Obesity Among Adults and Youth: United States, 2011-2014. NCHS Data Brief
  3. National Center for Health S. Health, United States. Health, United States, 2014: With Special Feature on Adults Aged 55-64. 2015.
  4. Ford ES, Dietz WH. Trends in energy intake among adults in the United States: Findings from NHANES. Am J Clin Nutr. 2013;97(4):848–53.
  5. U.S. Department of Agriculture, Office of Communications. “Profiling Food Consumption in America,” Chapter 2, Agriculture Fact Book, 2001-2002, 2003
  6. Wright J, Kennedy-Stephenson J, Wang C, McDowell M, Johnson C, National Center for Health Statistics. Trends in intake of energy and macronutrients--United States, 1971-2000. Morb Mortal Wkly Rep. 2004;53(4):80–2.
  7. Bleich SN, Wang YC, Wang Y, Gortmaker SL. Increasing consumption of sugar-sweetened beverages among US adults: 1988-1994 to 1999-2004. Am J Clin Nutr. 2009;89(1):372–81.
  8. Brownson RC, Boehmer TK, Luke D a. Declining rates of physical activity in the United States: what are the contributors? Annu Rev Public Health [Internet]. 2005;26:421–43.
  9. Church TS, Thomas DM, Tudor-Locke C, Katzmarzyk PT, Earnest CP, Rodarte RQ, et al. Trends over 5 decades in U.S. occupation-related physical activity and their associations with obesity. PLoS One. 2011;6(5).
  10. Hall KD. What is the required energy deficit per unit weight loss? Int J Obes. 2008;32(3):573–6.
  11. McCrory MA, Burke A, Roberts SB. Dietary (sensory) variety and energy balance. Physiology and Behavior. 2012. p. 576–83.

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Comments: 1
  • #1

    Lorac (Friday, 18 June 2021 10:00)

    The food that we all need is spiritual food!!! So better to change your perspective
    before man becomes extinct !�