Insulin 101: Your Blood Sugar Regulator
In a previous post, I explained the different kinds of carbohydrates and how they’re broken down and absorbed into your bloodstream. You can’t discuss carb metabolism without learning about insulin - the key player that unlocks our cells and gets glucose (carbs) to where it needs to go.
What Is Insulin?
Insulin is a hormone made by your pancreas, often called the “key” that unlocks your cells, allowing glucose to enter and be used for energy.
Here’s how it works if you don’t have any issues:
You eat a meal with carbs
Glucose enters your bloodstream
Your pancreas releases insulin
Insulin “unlocks” your cells, letting glucose in
Glucose is used for energy or stored for later use (fat/energy)
When working well, your blood sugar stays in a healthy range, think rolling hills. When this system does not work well, your blood glucose can look more like peaks and valleys.
What Is Insulin Resistance?
Insulin resistance happens when your cells stop responding to insulin as effectively. Imagine the “locks” on your cells getting rusty—insulin keeps knocking, but glucose has a harder time getting in.
To compensate, your pancreas makes more insulin to try to keep blood sugar levels normal. Over time, this can wear out your pancreas and lead to higher blood sugar, higher insulin levels, and eventually prediabetes or type 2 diabetes.
When I was in grad school, I remember learning about this and having a difficult time understanding that we actually want insulin sensitivity. For whatever reason, I couldn’t connect the dots that a ‘sensitivity’ to insulin was positive — but it is! So, sensitive = positive in this case, resistance = a challenge.
What Causes Insulin Resistance?
It’s complex and varies from person to person, but common contributors include:
Genetics and family history
Excess body fat, especially around the midsection
Lack of physical activity
High intake of ultra-processed carbs and sugary foods
Chronic stress or poor sleep
Important: You can be thin and still have insulin resistance… it’s not just about weight.
This graph shows the impact of your blood glucose levels when you pair carbs with a protein source. Your blood sugar levels will rise and fall more gradually (i.e. rolling hills versus peaks and valleys):
Source: Evaluation of the Effect of Macronutrients Combination on Blood Sugar Levels in Healthy Individuals
What Helps Improve Insulin Sensitivity?
The good news: insulin resistance can often be improved with lifestyle shifts. A few suggestions:
Movement: Regular exercise, or a small win that’s very beneficial, is walking after meals, so your cells can use glucose more efficiently
Balanced meals: No carb stands alone! Generally, try to eat carbs with protein, fiber, and/or healthy fats. This slows digestion and reduces blood sugar spikes
Sleep + stress: Both have a big impact on insulin sensitivity
Consistency: Small daily habits and being consistent matter in the long run
