These are the factors I'm aware of that can contribute to insulin resistance, listed in approximate order of importance. I could be quite wrong about the order-- this is just my best guess. Many of these factors are intertwined with one another.
- Cellular energy excess
- Physical inactivity (related to #1)
- Inflammation (related to #1 and others)
- Very low carbohydrate intake (less than 10%)
- Insulin resistance in the brain
- Low birth weight/size
- Inappropriate micronutrient status and insufficient protective phytochemical intake
- Smoking tobacco
- High heat cooking
- Excessive physical or psychological stress
Genetics and birth weight are not modifiable factors in people who are already born, however proper maternal nutrition can reduce the risk of having a low birth weight baby, setting the stage for lifelong health.
For those of us who have already arrived in this world, here are things we can do to prevent and often reverse insulin resistance. I'm not a medical doctor, and this is not medical advice; these are simply ideas to consider. It's always best to discuss health-related decisions with a skilled physician who understands your specific health challenges and goals.
- Eat an omnivorous diet centered around whole foods, simply prepared in the home using gentle cooking methods. It should be a diet that allows the maintenance of a healthy weight and does not favor overeating. It doesn't necessarily have to be low in palatability/reward, but avoiding energy-dense hyper-palatable/rewarding foods is always a good idea (baked goods, chips, pizza, candy, fast food, ice cream, etc.-- you know what your own trigger foods are), and people who carry excess body fat may benefit from further reducing food reward (1). Minimize liquid calories, particularly sweetened beverages and beer. Minimize refined and industrially processed food, particularly foods containing flours, added sugars, and refined seed oils, as well as restaurant food. This does not necessarily mean reduce unrefined starch intake. Favor fresh foods rather than cured and preserved items. Obtain omega-3 fatty acids from seafood, pastured animal foods, green vegetables and/or flax. Include abundant vegetables and fruits in the diet that provide a variety of fermentable fibers, protective phytochemicals such as polyphenols, and minerals such as magnesium. Avoid a very low carbohydrate intake (less than 10% of calories).
- Lose fat if you are overweight, to the extent that is achievable. Even small losses help.
- Exercise. Anything is better than nothing; daily is best even if it's only walking.
- Don't smoke.
- Get your serum ferritin checked (a marker of iron status) if you are a man, post-menopausal woman, or pre-menopausal woman who does not menstruate. If it's on the high side, consider giving blood to reduce it.
- Find ways to manage stress constructively, and optimize sleep duration and quality. Meditation can be very helpful in this regard (2). Don't overtrain yourself physically.