One possibility: we have been collecting learning to use our feet less throughout life.
"In 1969, 48 percent of children 5 to 14 years of age usually walked or bicycled to school (The National Center for Safe Routes to School, 2011).
In 2009, 13 percent of children 5 to 14 years of age usually walked or bicycled to school (National Center, 2011).
In 1969, 41 percent of children in grades K–8 lived within one mile of school;
89 percent of these children usually walked or bicycled to school (U.S. Department of Transportation [USDOT], 1972).
In 2009, 31 percent of children in grades K–8 lived within one mile of school;
35 percent of these children usually walked or bicycled to school (National Center, 2011)."
The amount of calories burnt through exercise is completely negligible. For instance running a mile at a good pace will generally burn around 100 calories, the same as you get from eating about one banana, or about drinking about half a bottle of Coke.
Exercise does have many positive metabolic and other benefits, but not anywhere enough to be a causal explanation on its own. If people started walking 5 miles a day, every day, not only would there still almost certainly be a widespread and growing obesity epidemic, but there's even an argument that it could be worse. Increases in activity tend to drive increases in hunger which will typically surpass caloric deficits if somebody is not actively controlling their diet, in which case they would not be fat in the first place.
This is made even worse by misleading advertising which will do things like showing fit athletes drinking Gatorade, Coke, etc during their training or competition. And somebody goes and does a couple of miles on a training bike and does the same thing - which is going to send their net caloric input skyrocketing.
I can regulate my weight by doing sports regularly or not with zero conscious attempts to change what I eat. And yes, non sports like taking daily walks have measurable effects too on me.
People who stop doing sports suddenly gain weight. People who get into sports habit like running or swimming slowly loose weight.
So, imo, this uber simplified model of just don't work like that.
Exercise does more than just use calories, it also changes blood glucose profiles, and I suspect lots of other metabolic things too, given how impactful it is on general health. It's distinctly plausible those things influence weight.
Proper physical activity burns a lot of calories, especially when its cold. It also changes some metabolic components, so not just the burning alone has an effect. It will not necessarily lead to hunger surpassing calorific deficits (and at very high activity it isn't even possible to eat enough to cover the deficit).
On the other hand, 50 calories x 365 days a year x 20 years x 5,000 calories per lb of weight = 75 lb of additional weight.
> Increases in activity tend to drive increases in hunger
As far as I know, certain types of high intensity exercise do so but not necessarily all exercise.
Yeah, I always get a bit amused when people point to one sole food or environmental issue ("microplastics!" says one comment) to blame for the obesity epidemic, when there are two glaringly obvious pieces of data:
1. As another commenter posted, total calories consumed per capita has gone up considerably since 1970.
2. As you posted, we move a lot less than we used to. There are tons of studies that confirm this across a number of different metrics (e.g. average grip strength has gone down considerably since the 80s, https://www.npr.org/sections/health-shots/2016/06/13/4815909... ).
We eat a lot more, of more foods that have higher calorie-to-nutrient ratios than we used to, and we move a heck of a lot less.
Yeah I'd believe a stronger sedentary lifestyle is the biggest factor in the waste line stagnation if the diet is not the same.
They did not have omnipresent smartphones in 1970.
It's probably multifactoral. For example, here's a recent provocative paper from a highly respected researcher (John Speakman) arguing metabolic rates have actually slowed since then: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10445668/
A massive increase in environmental plastics may also have something to do with it.
"The scientists theorize relationships among the global increase of plastics production, human exposure to microplastics, and the global increase of overweight and obesity in populations." https://www.niehs.nih.gov/research/programs/geh/geh_newslett...
The obvious answer is more calories. The obvious answer for why more calories is pretty obvious to non-Americans - your portion sizes are crazy, albeit everyone else in the world is catching up. Even if you buy a "healthy" meal in a quick service restaurant or as a pre-packaged retail product, the smallest portion size is still likely to be grossly excessive.
The obvious answer for why portion sizes are increasing is that food keeps getting cheaper, in particular relative to other costs in the food service industry. The traditional formula for restaurant pricing is 1/3 ingredients, 1/3 labour and 1/3 overheads; if your food costs have decreased over time but your rent and labour costs continue to increase, it's natural to increase portion sizes to maintain the appearance of value-for-money. The same would apply (to a moderately lesser extent) to convenience foods sold at retail. This has a quite drastic anchoring effect - when you normalise excessively large portions, reasonable portions seem meagre.
I think a major factor is that today people eat a lot of food designed by engineers to maximize sales. Designs that makes people overeat probably increases sales so they optimize for that.
So we should expect people to continue to get fatter as we get better at engineering food.
Note that I don't think that engineered food is inherently bad, just that today most food are engineered to be unhealthy because that is better for sales.
What about them? Are they designed to make you overeat? Or do they fill you up? I don't know which is why I ask. It is possible that they regulated things differently or their food companies had different values so they engineered snacks and fast food to not make you overeat.
As I said, engineering food isn't bad in itself, it depends on what goals you have when you engineer it. Just because Japanese people eat a lot of engineered food doesn't mean it is bad for them if that food wasn't engineered to make them fat.
Many say they slim down as they visit Japan, so I wouldn't rule it out.
What I'd want to see is if two countries that has the same snacks available had vastly different outcomes. But as far as I know most countries has domestic snacks so it varies wildly around the world. For example, why is Czechia much fatter than Slovakia? They were the same country 30 years ago.
Sugar's effect to 1970s waistlines would be determined by preceding decades. Insulin tolerance and other MBS things develop slowly over a person's life.
One simple explanation is protein. Modern diets have terribly low protein levels, and much of that protein comes from sources with extremely poor digestibility [1], meaning the effective protein consumption levels are even worse than they seem.
Protein is a major appetite suppressant. I'd read this but never really realized how true it is until starting on a protein heavy diet. I now eat near 500g of chicken breast a day, and by the end of the day I'm basically having to force feed myself. Yet 500g of chicken breast is less than 800 calories! And the other stuff is just to balance out my diet.
And I love eating as much as anybody else. But you simply cannot eat that much when you're on a protein heavy diet. Finding data on protein consumption rates over time is difficult, but I'd hypothesize we were probably much higher on effective protein consumption in the past. I know absolutely nobody that regularly had something like 'steak and eggs' for breakfast, yet it seems that was indeed a thing at some point.
One possibility: we have been collecting learning to use our feet less throughout life.
"In 1969, 48 percent of children 5 to 14 years of age usually walked or bicycled to school (The National Center for Safe Routes to School, 2011). In 2009, 13 percent of children 5 to 14 years of age usually walked or bicycled to school (National Center, 2011). In 1969, 41 percent of children in grades K–8 lived within one mile of school; 89 percent of these children usually walked or bicycled to school (U.S. Department of Transportation [USDOT], 1972). In 2009, 31 percent of children in grades K–8 lived within one mile of school; 35 percent of these children usually walked or bicycled to school (National Center, 2011)."
[Source](http://guide.saferoutesinfo.org/introduction/the_decline_of_...)
The amount of calories burnt through exercise is completely negligible. For instance running a mile at a good pace will generally burn around 100 calories, the same as you get from eating about one banana, or about drinking about half a bottle of Coke.
Exercise does have many positive metabolic and other benefits, but not anywhere enough to be a causal explanation on its own. If people started walking 5 miles a day, every day, not only would there still almost certainly be a widespread and growing obesity epidemic, but there's even an argument that it could be worse. Increases in activity tend to drive increases in hunger which will typically surpass caloric deficits if somebody is not actively controlling their diet, in which case they would not be fat in the first place.
This is made even worse by misleading advertising which will do things like showing fit athletes drinking Gatorade, Coke, etc during their training or competition. And somebody goes and does a couple of miles on a training bike and does the same thing - which is going to send their net caloric input skyrocketing.
I can regulate my weight by doing sports regularly or not with zero conscious attempts to change what I eat. And yes, non sports like taking daily walks have measurable effects too on me.
People who stop doing sports suddenly gain weight. People who get into sports habit like running or swimming slowly loose weight.
So, imo, this uber simplified model of just don't work like that.
Exercise does more than just use calories, it also changes blood glucose profiles, and I suspect lots of other metabolic things too, given how impactful it is on general health. It's distinctly plausible those things influence weight.
Proper physical activity burns a lot of calories, especially when its cold. It also changes some metabolic components, so not just the burning alone has an effect. It will not necessarily lead to hunger surpassing calorific deficits (and at very high activity it isn't even possible to eat enough to cover the deficit).
On the other hand, 50 calories x 365 days a year x 20 years x 5,000 calories per lb of weight = 75 lb of additional weight.
> Increases in activity tend to drive increases in hunger As far as I know, certain types of high intensity exercise do so but not necessarily all exercise.
1 reply →
Yeah, I always get a bit amused when people point to one sole food or environmental issue ("microplastics!" says one comment) to blame for the obesity epidemic, when there are two glaringly obvious pieces of data:
1. As another commenter posted, total calories consumed per capita has gone up considerably since 1970.
2. As you posted, we move a lot less than we used to. There are tons of studies that confirm this across a number of different metrics (e.g. average grip strength has gone down considerably since the 80s, https://www.npr.org/sections/health-shots/2016/06/13/4815909... ).
We eat a lot more, of more foods that have higher calorie-to-nutrient ratios than we used to, and we move a heck of a lot less.
Yeah I'd believe a stronger sedentary lifestyle is the biggest factor in the waste line stagnation if the diet is not the same. They did not have omnipresent smartphones in 1970.
Heck, back in my days, we kids at least had to walk to each other's house to play video games together.
I wonder how jobs have changed too. I started gaining weight when I switched from a delivery job to a lab job.
It's probably multifactoral. For example, here's a recent provocative paper from a highly respected researcher (John Speakman) arguing metabolic rates have actually slowed since then: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10445668/
But two decades of "fat doesn't make you fat" probably didn't help, and neither did the continued trend of increasing empty calories from cheap vegetable oils, especially soybean oil: https://thedietwars.com/why-are-americans-getting-fatter-a-f...
https://www.ers.usda.gov/webdocs/charts/59529/indicators_goa...
>Added fats and oils provide more calories per day for the average American than any other food group
EDIT: I think most Americans would be shocked to discover that their "favorite" food group is added fat/oil.
A massive increase in environmental plastics may also have something to do with it.
"The scientists theorize relationships among the global increase of plastics production, human exposure to microplastics, and the global increase of overweight and obesity in populations." https://www.niehs.nih.gov/research/programs/geh/geh_newslett...
The obvious answer is more calories. The obvious answer for why more calories is pretty obvious to non-Americans - your portion sizes are crazy, albeit everyone else in the world is catching up. Even if you buy a "healthy" meal in a quick service restaurant or as a pre-packaged retail product, the smallest portion size is still likely to be grossly excessive.
The obvious answer for why portion sizes are increasing is that food keeps getting cheaper, in particular relative to other costs in the food service industry. The traditional formula for restaurant pricing is 1/3 ingredients, 1/3 labour and 1/3 overheads; if your food costs have decreased over time but your rent and labour costs continue to increase, it's natural to increase portion sizes to maintain the appearance of value-for-money. The same would apply (to a moderately lesser extent) to convenience foods sold at retail. This has a quite drastic anchoring effect - when you normalise excessively large portions, reasonable portions seem meagre.
I think a major factor is that today people eat a lot of food designed by engineers to maximize sales. Designs that makes people overeat probably increases sales so they optimize for that.
So we should expect people to continue to get fatter as we get better at engineering food.
Note that I don't think that engineered food is inherently bad, just that today most food are engineered to be unhealthy because that is better for sales.
There are lots of "common wisdom" answers to this but almost every one spins out pretty quickly. Look at the snack foods readily available in Japan.
What about them? Are they designed to make you overeat? Or do they fill you up? I don't know which is why I ask. It is possible that they regulated things differently or their food companies had different values so they engineered snacks and fast food to not make you overeat.
As I said, engineering food isn't bad in itself, it depends on what goals you have when you engineer it. Just because Japanese people eat a lot of engineered food doesn't mean it is bad for them if that food wasn't engineered to make them fat.
Many say they slim down as they visit Japan, so I wouldn't rule it out.
What I'd want to see is if two countries that has the same snacks available had vastly different outcomes. But as far as I know most countries has domestic snacks so it varies wildly around the world. For example, why is Czechia much fatter than Slovakia? They were the same country 30 years ago.
I'm looking... https://youtu.be/lr4MmmWQtZM?t=34
2 replies →
Sugar's effect to 1970s waistlines would be determined by preceding decades. Insulin tolerance and other MBS things develop slowly over a person's life.
In spite of sugar, a lot of people went hungry.
You can note that average male height in the US continued increasing up until the late 1980s.
That points to a general caloric deficit up until roughly 1990--which is roughly where we claim the "obesity epidemic" kicks off.
Also, a graph of sugar doesn't include caloric fillers like "soy protein" which now seems to be in everything.
> You can note that average male height in the US continued increasing up until the late 1980s.
Fat is estrogenic, and estrogen accelerates growth plate fusion.
> Fat is estrogenic
I meant bodyfat specifically
That part is pretty clear. People are eating more calories than they did in 1970. The more difficult question is: why are they doing that?
One simple explanation is protein. Modern diets have terribly low protein levels, and much of that protein comes from sources with extremely poor digestibility [1], meaning the effective protein consumption levels are even worse than they seem.
Protein is a major appetite suppressant. I'd read this but never really realized how true it is until starting on a protein heavy diet. I now eat near 500g of chicken breast a day, and by the end of the day I'm basically having to force feed myself. Yet 500g of chicken breast is less than 800 calories! And the other stuff is just to balance out my diet.
And I love eating as much as anybody else. But you simply cannot eat that much when you're on a protein heavy diet. Finding data on protein consumption rates over time is difficult, but I'd hypothesize we were probably much higher on effective protein consumption in the past. I know absolutely nobody that regularly had something like 'steak and eggs' for breakfast, yet it seems that was indeed a thing at some point.
[1] - https://en.wikipedia.org/wiki/Digestible_Indispensable_Amino...
Meat consumption per capita has almost doubled since 1960: https://ourworldindata.org/grapher/per-capita-meat-consumpti...
Meat consumption is associated with higher BMI: https://pubmed.ncbi.nlm.nih.gov/32443920/ (summarized in: https://www.news-medical.net/news/20200615/Vegetarians-have-...)
2 replies →