Craving Cake Instead of Carrots? Blame Millions of Years of Evolution
Key Takeaways
Your wants and needs have been shaped by over 5 million years of evolution to accomplish one goal: live long enough to pass on your genes.
It was more important for survival to cram every available calorie down our throats, push past hunger cues, and store the excess energy for later rather than merely eating to satiety.
In today’s food environment of abundance for most of the population, this evolutionary strategy simply leads to obesity, diabetes, and frustration.
The reason we crave cake and not carrots is that the consumption of the cake compared to carrots promises to keep us alive for significantly longer and elicits a much greater pleasure response.
The two most effective tools to combat our misguided eating instincts are discipline and consistency.
Full Story - Craving Cake is Not Your Fault
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The 90’s were SO long ago, right? WRONG. 30 years is just a fraction of the time humans have been on Earth. Here’s a concept you can’t possibly grasp: humans have been around for ~200,000 years and our ancestors for over 5 million years (1, 2). Over this time, your wants and needs have been shaped to accomplish one goal - live long enough to pass on your genes.
Along the way, the development of consciousness muddied the waters, but it is indisputable that your deepest instincts are driven by this goal. I don’t know why or how all this happened, but I do know that thousands of years of evolution has made it tough to be healthy today.
Pop Quiz - Craving Berries and Caribou
It’s 200,000 years ago, you have not eaten in an entire week, and you are starving, irritated, and sick and tired of coming back empty-handed from your caribou hunts. On your way back to the campsite, you stumble across a gorgeous, ripe berry bush. Do you
A. Devour every single berry before you can even think
B. Bring them back to share with your tribe
C. Put them in Tupperware for next week’s meal prep
If you had chosen B or C, you would not have survived long enough to pass on your genes, and your story would end with starvation rather than continuing with a belly full of berries. The answer is A, “Devour every single berry before you can even think”, and herein lies the deep-seated cause behind the obesity and metabolic disease crisis of modern times.
The projected obesity rate for most states in 2030 is between 40-60% (3).
How Evolution Works Against Us
For the vast majority of human history, calories were scarce. Except for the most recent portion - and I’m talking less than 1%- of the previous 200,000 years, Homo Sapiens have had limited access to precious, life-preserving calories. Just as you feel a rush of excitement when you find a $20 bill on the ground or come up with the correct answer on Final Jeopardy, finding calorie-dense food was a rare and titillating experience.
It has become ingrained among our species to prioritize finding and consuming high calorie foods because, if successful, it means preventing our own demise. It need not be said, but having excess fat and being alive is much better than being shredded and dead. When the opportunity arose, it was more important for survival to:
Cram every available calorie down our throats
Push past hunger cues
Store the excess calories for later as body fat, rather than merely eating to satiety (the point of feeling full)
Go to sleep with a full belly, ready to run, hunt, and forage again tomorrow
This strategy of eating every morsel in sight has been incredibly effective, allowing humans to survive, reproduce, and discuss evolution and appetite today. However, in today’s food environment of abundance for most of the population*, death by starvation is not a primary concern. Now, with more available calories than we could ever imagine, this trusted evolutionary strategy simply leads to obesity, diabetes, and frustration.
*I understand that not everyone in America or the world has access to enough calories and that overconsumption is a lucky, albeit real, problem to have. If you’d like to help end world hunger, you can do so here (4).
Why Doesn’t “Healthy” Food Taste the Best?
As a kid, it always bewildered me that apples and green beans were supposedly “good for me”, but my taste buds preferred bagels and brownies. Not yet familiar with evolutionary biology, the paradox puzzled me; shouldn’t my body prefer nutrition dense food instead of the junk food, since the former made me healthy and the latter made it more likely to overeat and gain fat?
It’s no coincidence that swallowing super tasty, ultra-processed sweets is more rewarding than choking down a chewy, fibrous stalk of broccoli. As soon your ice cream sundae touches your tongue, your brain explodes with:
This is FANTASTIC!
This will keep me alive for at least a few more days!
Yum, yum, yum - give me more!
On the other hand, in response to raw broccoli the brain mutters:
Eh
I guess this is better than nothing
I’ll eat more, but only if I have to
Moreover, if we stumbled across honey, meat, or any other energy-dense food in nature, it was:
Rare
Exciting
Important
While finding vegetables or other low-calorie-dense food was:
Common
Boring
Still good but not nearly as important
The reason we crave cake and not carrots is that the consumption of the cake, compared to carrots, promises to keep us alive for significantly longer. And what is the most important human drive? Survival!
Our brains are smart (or maybe my brain just told me to write that to stroke its ego?) and they know exactly how to reinforce behavior. Because calorically dense food is beneficial for our survival, in response to tasting it, the brain releases tons of feel-good chemicals to encourage us to do whatever it takes to find and taste that food again in the future. We even have a neural circuit in our brains that tells us to eat as many calories as possible until all the food is gone, pushing way past the point of feeling full (5).
Evolution Favors Short Term Survival Over Long Term Health
It was not until I figured out that taste buds are wired for survival and not for developing 6-pack abs that it all started to make sense. Obesity and other metabolic diseases are modern conditions that pit foresight and delayed gratification against thousands of years of hardwired human biology.
Though unfortunate for our diet efforts and waistlines, this evolutionary instinct is not futile. Just as being terrified of bears keeps you alive and being drawn to the attractive man/women increases your chances of producing fruitful offspring, your hunger for calorie-dense foods is extremely beneficial in the eyes of evolution.
Evolution doesn’t care if you live a happy and healthy life, it cares only about survival and reproduction. Tragically, although the instinct to over-consume is life-saving, it steers us toward worse health and, in today’s culture, decreases our chances of attracting a fertile mate. Quite a paradox!
Again, this life saving instinct was extremely beneficial for the overwhelming majority of human existence. But today, in a time of caloric abundance in which the corner 7/11 contains more calories than entire villages did just a few thousand years ago, it is a driving force behind the obesity and metabolic disease pandemic.
Wrap Up
Today, we must resist our evolutionary urge to stuff our face all day, every day in order to optimize our health and longevity. Most commonly, we fight this urge with frenzied workouts, fad diets, and fat-burning detox teas, but these tools have proven to be ineffective time and time again.
By understanding history, evolutionary biology, and behavior change we are better able to delineate between clever marketing of useless products and evidence-based, constructive strategies. Though wildly unsexy, the two most effective tools to combat our misguided eating instincts are discipline and consistency. The discipline to:
Find exercise modalities you enjoy
Perform a sustainable workout routine
Prioritize frequent bouts of activity throughout the day
Find convenient ways to prepare healthy foods
Eat mindfully and chew slowly
Avoid ultra-processed, calorically-dense foods (most of the time)
Consume nutritious foods, including:
A lot of protein
A lot of fiber (fruits, vegetables, nuts, legumes)
High volume, low calorie dense foods
A lot of water
A commitment to these habits, along with the consistency to do it week after week, year after year for a lifetime is the only chance we have to defeat our instincts and stave off chronic metabolic disease.