The Thrifty Gene Theory and Modern Obesity
Are Our Genes Responsible for Obesity and Diabetes?
In 1962, geneticist James Neel proposed a very simple idea of why people get diabetes. He suggested that some individuals were born with a "thrifty gene." It was a mutation that allowed hunter-gatherer populations, specifically child-bearing women to gain more weight, especially when food was plentiful.
These fatter individuals would then have more of a cushion, to survive when food became scarce. The "thrifty gene" was then passed down to future generations, because the fatter individuals were the ones most likely to survive.
Today, the majority of people live in a world where food is abundant, all the time. We're eating and preparing for a famine that never comes. It's the mismatch between our genetic heritage and the modern environment that leads to chronic obesity and health problems like diabetes.
It's a very neat theory that matches up nicely with how most people think about being overweight. "It's not my fault, it's my genetics!"
There's just one tiny problem with the hypothesis. The little data that exists, doesn't support the theory. From analysis published in the American Journal of Human Genetics (February 2015) to a study in Biology Letters (January 2015), it seems prehistoric people ate more often, not less, than later societies that grew their food.
Hunter-gatherer societies weren't under constant threat of famine. They were more mobile and migrated to locations where food was most plentiful while farmers were much less likely to move when problems arose.
Because farmers were so tied to their land, when crops failed they weren't prepared to live off what the wilderness provided. Famine now appears to have been more prevalent in "modern" societies than the primitive ones.
With the demise of the thrifty gene hypothesis, several other theories have arisen to explain our growing levels of diabetes and obesity. Researchers are trying to pin the blame on modern aggression control, genetically unknown foods, climate adaptations and something called the thrifty phenotype theory that blames the mother for providing poor nutrition in the womb.
All those ideas help make us feel less guilty about our growing waistlines and increasing illness, but they aren't addressing the real problem. To paraphrase Shakespeare, “The fault, dear reader, is not in our genetics, but in our actions.”
Problem Number 1 - We Don't Do Physical Stuff
Go back to the year 1900. There were few labor-saving devices and over 60% of Americans lived in rural communities. Taking care of farm animals and crops was extremely physical work that burned hundreds of calories a day.
Household chores like cooking, washing clothes and cleaning were done without the benefit of food processors, dishwashers, washing machines or vacuum cleaners. Factory workers had to cut, hammer and weld things by hand and most people worked 6 days a week. The number of calories people burned each day simply by living, was dramatically higher than we experience today.
In the 1980s America was in the information revolution. Only 26% of Americans were still living in rural communities. Fewer and fewer jobs required physical labor and the average American waistline had ballooned. But it was going to get worse.
Researchers from the Stanford Medical School found that adult women who had no physical activity in their spare time, increased from 19% in 1994 to 52% in 2010. The number of adult men who had no physical activity in their spare time jumped from 11% in 1994 to 44% in 2010.
In that same time period, the average body mass index (BMI) for women increased .37% per year, even though there was no evidence they ate more calories. Our inactive lifestyle is killing us.
Problem Number 2 - Corporate Food Sales
The goal of a corporation is to sell more stuff. That doesn't matter if the stuff is pants, plates or peanut butter.
With the food industry, there are two fundamental approaches. The first is through advertising. Companies spend hundreds of millions of dollars every year to convince you that what they're selling is amazing, and you've got to get some. Now before you shake your head and claim advertising does not affect YOU, consider this.
Stanford University pediatrics researcher Thomas N. Robinson conducted a test with 63 children, with an age range from 3 to 5 years. Researchers took two identical food samples from behind a screen and placed them in front of the kids. One set of food came in a plain wrapper, cup or bag and the other came in a clean, unused McDonald's wrapper, cup or bag. Then the kids were asked which one they liked best.
In every single type of food test, the majority of kids said the "best" foods were the ones that came with McDonald's logo, even though that was the ONLY difference between the two choices. 77 percent liked the "McDonald's" fries better, 61 percent said the "McDonald's" milk was better and 59 percent said the "McDonald's" chicken nuggets were better than the generic ones.
When children as young as three are showing a preference for McDonald's fast food, you know the advertising is working.
The second thing food companies do is work on the food itself. Sweet sells. Salty sells. But when you combine the two, they sell more than either one on its own. More and more foods are engineered to activate multiple pleasure centers and keep you buying.
Which brings me to the flavorists. Food companies want every bite you take to be an amazing explosion of flavors in your mouth that keep you drooling in anticipation. But the trick is, they can't let the flavor last too long. Once you've swallowed, the taste should already have dropped by half, so you've got to take another bite to get it back.
By carefully manipulating how the flavors react in our mouths, food companies literally create addictive foods. We eat more, their profits go up and everyone gets even fatter.
Problem Number 3 - Time
We're so busy doing "stuff" we don't have time to take care of what matters. Instead of cooking healthy meals, we grab something from a drive-thru, have it delivered or pour it out of a box. Most of the time the choices we make are much higher in calories, fat and sugar than traditional meals made from scratch.
Combine these three modern problems and what you get, is exactly what we've got. A society where over 65% of the population is either overweight or obese. You don't have come up with complicated or exotic theories of human evolution, just look around.
It's time to stop blaming genetics and start taking control of our actions. Check out our links on some things you can start doing today.
UPDATE - Uricase Mutation
A variation of the thrifty gene hypothesis is a mutation in a gene called uricase. It helps to convert fructose (fruit sugar) into fat.
The idea is that the uricase mutation makes the conversion from fructose into fat so efficient, it predisposes humans to obesity and diabetes. By lowering elevated uric acid levels, you could theoretically lower fat storage, lessen obesity, diabetes and heart disease.
While research is ongoing, it's amazing to think scientists have to construct such elaborate scenarios to account for the growing obesity problem. Yes, genetics do play a part in how efficiently we convert calories into fat. But that's not the primary problem with modern society. The problem is we're eating too many calorie-dense foods with low nutritional value. When we cut back on the calories, the weight drops off!
Quit blaming your genetics and put down the plate of junk food.
UPDATE - Obesity Gene and Weight Loss
It can be difficult to take responsibility for what's wrong in our lives. One of the ideas people have latched onto is that they're overweight because of their genetics. In fact, geneticists know some genes can predispose people to gain weight.
However, those genes don't prevent or hinder people from losing weight if they regularly exercise and eat a healthy diet. In fact, when people WITH the "obesity gene" (also known as the FTO genotype) were compared to those WITHOUT the gene, BOTH dropped weight at exactly the same rate.In a quote to Time.com, the leader of the study, John Mathers said, "We think this is good news - carrying the high risk [form of the gene] makes you more likely to be a bit heavier, but it shouldn't prevent you from losing weight."
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