With fitness, human evolution will win and ‘art’ confused this
The human body has evolved over millions of years to do things in certain ways – ways that enabled people to survive. In a process commonly referred to "natural selection," those with abilities and attributes best suited to the environment lived or reproduced more, those less suited died or reproduced less.
The results of this evolution have had some key results that directly impact our fitness goals (and yes, I am a Christian that believes in evolution).
However, there has been an iconic piece of artwork that adds a lot of confusion to the conversation - it's of a series of humans evilving in a nice progression from ape-like to human-like, in a nice evenly psaced amnner. This often used image – or versions of it – was created by an artist to fit nicely onto a piece of paper.
The problem is that the image implies an evolution with each stage lasting about the same amount of time (and on a side issue, the timeline should look more like tree branches than a stick, but that's a different issue). The image's timeline is not "to scale."
Some have used the image with dates written below it, which helps to correct some of the issues, but it still is visually misleading.
But, to be truly accurate on the timeline issue, the images should be spaced as this:
If you look at the above it is clear why this "to scale" timeline was not used – it's hard to read and makes for 'bad art.'
So why do this matter? The 'artistic' version is, at the least, visually misleading, since;
1) We had to hunt and gather all of our food – actually physically work to get it – for most of our time on earth – about 99% of it. And, on the artistic version, it is lost that for over 80% of the time this hunting was done without somewhat modern weapons – it was more labour intensive.
2) We started to use fire about three quartersof the way into our existence so we had 3-million years of life without fire and 1-million with it. Fire allowed us to cook food, making it soft and much easier to chew and eat. In fact, our modern processed foods allow us to eat 5 – 6 times as much food per hour as our distant ancestors. For a great piece on this read check out: "The Way We Eat Now" by Craig Lambert in Harvard Magazine, May-June 2004. Or go here: http://harvardmagazine.com/2004/05/the-way-we-eat-now.html
3) So, most of our time on earth was about a food shortage, not a food surplus.
Put these three things together and you get this: Today we have an ability to easily consume 5-6 times as much food per hour as our ancestors and we don't have to do anything to get it (we can call for home delivery). So it's easier to get fat. Remember, if we take in more calories than we burned to get it and before the next feeding, we get fatter.
This entire series of items is compounded if we try a short-term diet – we make matters worse because of – once again – evolution. You see, our bodies have sort of a "pre-set fat-storage amount." Over the past few million years, if we had a time of famine, those with better food/energy/fat storage lived and the others died (we did not have refrigerators or bulk food storage abilities back then). And the bodies that adjusted their fat-storage level higher after the famine were more likely to survive the next famine.
This worked great until we came up with processed foods, home delivery, grocery stores, drive-through restaurants, etc. Today we can get fat easier – since we don't need to physically do anything to get more than enough food to eat.
Today, when we decide to go on a short-term or "fix" diet, our body perceives it as a time of famine (stemming from evolution). Then, when the diet is over, our bodies - having evolved to adapt to this lack of food - pack-on more reserve food. So, it's easier and more likely for us to get fatter than we were before the diet - or body perceived "famine." For a complete explanation of this see "Why dieting doesn't usually work" by Sandra Aamodt at Ted.com or go here.
So today, we can get fat easier and when we do a quick fix diet, we will tend to get even fatter after the diet!
And it's all because we haven't had time to evolve to fit the new reality of "we don't need to do anything physical to eat." We are still stuck in our "hunter-gatherer" bodies.
1) Only eat the amount you've done enough work to metaphorically "catch"
2) Don't diet, change your entire eating pattern and lifestyle to fit for the long-term