Obesity: Is it the Canary in the Coal Mine?
The goal of people who work in healthcare should be to maintain health, rather than to rescue people from disease. As we think about how to maintain health, we need to consider what simple observations and interventions can successfully address aging and longevity.
Before we get to the simple part, I want to talk about some science. (Not a scientist? Read on anyway. It all will make sense, believe me.)
One pathway to longevity identified by science is to focus on the insulin receptor pathway. We’ve learned a lot about this biological process in the last few decades – both in the laboratory and with patients. It’s the mechanism that regulates how – and how well – your cells convert the sugars in your diet to energy and growth.
There are several lines of evidence that point to this pathway as an attractive target in longevity.
There have been many studies on longevity and a lot of theories about what might contribute to a person living longer. Some of the factors are internal – like the genes you inherit from your parents – that can’t be changed. The things you can change are what we call environmental factors. And the only environmental approach that reproducibly improves longevity is calorie restriction.
Simply put, people who eat less live longer.
Why? Because calorie restriction reduces the activation of the insulin receptor pathway. When this process slows, it sets off a series of “downstream” effects within the body’s cells. These include the important downstream activation events of Akt and mTOR (the target of rapamycin) and enables cells to remove damaged parts – organelles and mitochondria – through the process of autophagy (self-eating). Repairing damage makes the cells “younger” in biological terms.
(Interesting side note: We also know that the conserved longevity pathway Daf2 discovered in the worm c. elegans is a homologue of the insulin receptor. Another conserved longevity gene, Daf16 is a homologue to FOXO-3a, a forkhead transcription factor that is activated downstream of the insulin receptor. Send me a message if you want to discuss this.)
Here’s the simple part:
In his groundbreaking work Good Calories, Bad Calories, investigative journalist Gary Taubes reviewed all the literature he could find on nutrition and obesity. He started off believing that obesity was “more calories in and fewer calories burned off.” After his investigation, he came to the conclusion that obesity actually results from insulin receptor activation.
That is, consumption of foods that activate the insulin receptor causes us to store calories as fat. If we reduce activation of the insulin receptor, that may allow us to lose weight.
What foods activate the insulin receptor? Sugar and carbohydrates.
The USDA and the American Heart Association have recommended a low fat diet since 1961. Tellingly, that’s around the time the obesity epidemic accelerated. Since protein is fairly fixed in our diets, lower fats mean higher carbohydrates. In fact, the average American eats around 100 pounds of sugar per year.
Now, the World Health Organization (WHO) recommends that only 5 percent of dietary calories come from sugar – less than one can of a sugary soft drink per day.
Since activation of the insulin receptor may cause obesity and aging, the question becomes – will weight loss and reduced activation of the insulin receptor lead to health and youth?
Like the canary in the coal mine, our obesity epidemic may be a warning: we have accelerated the biological aging of our citizens. That process could be the basis of much of the cancer, heart disease, diabetes, and Alzheimer’s disease we see today – diseases of aging that are appearing in younger and younger people.
So, simply focusing on reduced sugar and carb intake and exercise (you’ll need to walk about 12,000 steps a day if you want to keep drinking sugary soda!) will interfere with the activity of the insulin receptor. You may not only lose weight, but get healthier and (biologically) younger!