What do heart disease, cancer, neurodegenerative diseases, and type 2 diabetes have in common? What should we look out for if we want to prevent them?
According to Peter Attia, insulin resistance is to blame for many lives being cut short. In his book Outlive, he argues that the key to avoiding physical and mental decline in old age is preventing four specific chronic diseases. Insulin resistance, he says, is a direct cause of these conditions.
Read more to learn how insulin resistance takes a toll on our long-term health.
Peter Attia on Insulin Resistance
According to Peter Attia, insulin resistance directly causes four chronic diseases: heart disease, cancer, neurodegenerative diseases (like Alzheimer’s and dementia), and type 2 diabetes. Insulin resistance is a main component of metabolic dysfunction.
(Shortform note: This kind of metabolic dysfunction (a precursor to type 2 diabetes) shares many symptoms with type 1 diabetes—for instance, fatigue and persistent hunger. Type 1 diabetes occurs when the pancreas fails to produce sufficient amounts of insulin due to a faulty autoimmune reaction. Insulin resistance is rarer in type 1 diabetics (because it’s not a prerequisite like it is for type 2). However, they can still contract insulin resistance in the same way: by overeating until their body forms intracellular fat inside muscle that blocks insulin signals. The only difference is that they form resistance to insulin injections rather than their body’s own insulin.)
How could metabolic dysfunction and insulin resistance cause four wildly different chronic diseases? Let’s examine all four.
First, extreme metabolic dysfunction is type 2 diabetes. Attia explains that you qualify for a diagnosis of type 2 diabetes when you reach a certain level of chronically elevated blood sugar and insulin resistance.
(Shortform note: Type 1 diabetes presents in the same way as type 2—elevated blood sugar and insulin resistance. The most reliable way to distinguish type 1 diabetes from type 2 is to test your blood for autoantibodies. Autoantibodies show that your immune system is damaging your pancreas, indicating type 1 diabetes.)
Second, metabolic dysfunction directly increases your risk of cardiovascular disease, Attia states. When your metabolism is dysfunctional, your blood pressure increases, damaging the walls of your blood vessels. This damage increases your risk of harmful cardiovascular incidents by causing plaque to build up along your vessel walls. This may eventually clog your blood vessels or force a clot into the bloodstream, causing a heart attack or stroke.
Third, metabolic dysfunction provides the perfect environment for cancer cells to grow. Attia explains that cancer cells consume more glucose than healthy cells do, and they use insulin to absorb these vast amounts of glucose. The more insulin is in your bloodstream, the more fuel is available for cancer cells to grow.
(Shortform note: Common cancer treatments including chemotherapy and steroid medications have the side effect of increasing blood sugar and insulin resistance, providing cancer cells with more fuel while killing them. This is part of the reason that treating cancer is so difficult. This reaction to cancer treatment also often exacerbates existing symptoms of metabolic dysfunction, such as high blood pressure.)
Finally, Attia asserts that metabolic dysfunction causes neurodegeneration: chronic damage to your brain. To function properly, the brain needs a lot of energy—typically in the form of glucose—and it depends in part on insulin to get the glucose it needs. In particular, the parts of the brain responsible for memory appear to be more dependent on insulin than other parts. If you trigger insulin resistance in the brain, the memory systems can’t get the energy they need, and neurodegeneration sets in.
The Role of Exercise and Nutrition
Attia states that, as long as your metabolism is relatively healthy, practicing the ideal exercise routine is more important than consuming the ideal diet. Although fixing your diet is essential if you’re suffering from intense insulin resistance, perfecting your diet yields far fewer health benefits than perfecting your exercise routine.
The Role of Sleep
Multiple studies suggest that poor sleep disrupts your metabolism, making metabolic dysfunction and chronic disease much more likely. Although researchers aren’t totally sure why this is, Attia theorizes that it’s because insufficient sleep puts your body into perpetual fight-or-flight stress. The stress hormone cortisol raises blood pressure and triggers the liver to release glucose into the blood. This can lead to insulin resistance and an increased risk of chronic disease.
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Like what you just read? Read the rest of the world's best book summary and analysis of Peter Attia's "Outlive" at Shortform.
Here's what you'll find in our full Outlive summary:
- A guide on how to extend the active and fulfilling part of your life
- How to circumvent the mental and physical decline that often comes with age
- The one chronic condition that can cause four of the most deadly diseases
