Today’s prompt, and the companion piece behind it.
Insulin Sensitivity
What’s the difference between insulin resistance and insulin sensitivity, and which do you want?
The Short Answer
Insulin sensitivity means your cells respond efficiently to insulin — a small amount of insulin effectively moves glucose into cells. Insulin resistance means your cells respond poorly — more and more insulin is required to do the same job. You want insulin sensitivity. Insulin resistance is a step toward type 2 diabetes. On the carbohydrate-insulin model it also promotes fat storage, makes weight loss harder and drives hunger, though the model’s own proponents call the human evidence inconclusive. The good news: insulin sensitivity can be improved through fasting, exercise, weight loss, and dietary changes.
Something to Sit With
Based on your eating patterns, activity level, and how you feel, where might you be on the sensitivity-resistance spectrum?
What changes would most improve your insulin sensitivity?
How does knowing this mechanism change how you think about eating and weight?
Learn More
What Insulin Does.
Insulin is a hormone released by the pancreas in response to eating, especially carbohydrates. Its primary job is to move glucose from the bloodstream into cells for energy or storage.
Think of insulin as a key that unlocks cell doors. When you eat, blood glucose rises. Insulin is released. Insulin “unlocks” cells. Glucose enters. Blood sugar returns to normal.
This system works well when cells respond efficiently to insulin’s signal.
Insulin Sensitivity: The Ideal.
When you’re insulin sensitive:
Small amounts of insulin work well. A little insulin effectively unlocks cells. Blood glucose is cleared quickly and efficiently.
Fat storage is minimal. Insulin promotes fat storage, so less insulin means less storage signal.
Fat burning is accessible. When insulin is low (between meals, during fasting), fat can be released and burned. With good sensitivity, insulin drops quickly after eating.
Hunger isn’t pushed by insulin. In the animal studies behind the carbohydrate-insulin model, increased hunger was the last link in a chain that began with high insulin, and on the model’s account good sensitivity keeps it from starting.[1]
Cells get what they need. Muscles and other tissues efficiently receive the glucose they require.
Insulin sensitivity is associated with metabolic health, easier weight management, stable energy, and lower disease risk.
Insulin Resistance: The Problem.
When you’re insulin resistant:
More insulin is required. Cells don’t respond well to insulin’s signal, so the pancreas produces more to compensate. Blood insulin levels are chronically elevated.
Fat storage is promoted. Elevated insulin suppresses the release of stored fat — that physiology is not disputed.[1] That chronically high insulin is therefore a primary driver of weight gain is the carbohydrate-insulin model’s proposal, and its own proponents call the human evidence inconclusive.[1]
Fat release is suppressed. That this keeps fat locked away even in a calorie deficit comes from animal studies.[1]
Hunger may follow. In those animal studies, increased hunger came last, after the changes in insulin, fat storage and energy expenditure.[1]
Cells remain starved. Despite high blood glucose, cells don’t receive it efficiently. This creates fatigue despite eating.
The pancreas works overtime. Eventually, it may fail to keep up, leading to type 2 diabetes.
Insulin resistance is associated with weight gain, difficulty losing weight, type 2 diabetes, metabolic syndrome, and increased cardiovascular risk.
How Resistance Develops.
Insulin resistance develops through:
Chronic overexposure to insulin, on one account. Eating frequently, especially high-carbohydrate foods, keeps insulin elevated.[1] One common explanation is that cells then become “deaf” to the constant signal, like background noise you stop hearing; that is a hypothesis rather than an established result.
Excess body fat. Fat tissue, especially visceral fat around organs, contributes to insulin resistance through inflammatory signals.
Lack of physical activity. Muscle is a major glucose-consuming tissue. Inactive muscles become less responsive to insulin.
Poor sleep. Even a few nights of poor sleep can induce temporary insulin resistance.
Chronic stress. Cortisol and other stress hormones contribute to insulin resistance.
The combination is particularly potent: eating frequently, moving little, sleeping poorly, staying stressed — modern life in a nutshell.
Improving Insulin Sensitivity.
Fasting. The idea is that breaks from insulin let cells resensitize. Be careful how much weight you put on this, because the species matter and the human trial is small. Much of the time-restricted-feeding work on insulin sensitivity is rodent work, and the species marker travels with it.[2] The human result worth knowing is narrower and better designed: in an isocaloric crossover trial — eight overweight men with prediabetes, five weeks per arm — eating earlier in the day improved insulin sensitivity without any weight loss, which is what lets it separate timing from calories.[3] Eight men is not proof; an isocaloric design is still the right kind of evidence.
Exercise. Both aerobic exercise and resistance training improve insulin sensitivity. Muscle contraction moves glucose into cells independent of insulin, and regular exercise makes cells more responsive.
Weight loss. Losing excess body fat, especially visceral fat, improves insulin sensitivity. Even modest weight loss produces significant improvements.
Lower carbohydrate intake. Fewer carbohydrates mean less insulin required.[1] Whether lower insulin then lets cells resensitize is the same hypothesis as above, not an established result.
Improve sleep. Adequate, quality sleep supports insulin sensitivity. Sleep deprivation worsens it.
Manage stress. Chronic stress impairs insulin sensitivity. Stress management practices help.
Specific foods. Some foods may help: vinegar, high-fiber foods, foods low on the glycemic index. Avoiding ultra-processed foods and refined carbohydrates may help too.
The Bigger Picture.
Insulin sensitivity vs. resistance isn’t a binary — it’s a spectrum. You can be anywhere on it, and your position can shift.
Some people who struggle with their weight have insulin resistance without knowing it. On the carbohydrate-insulin model, that mechanism rather than willpower is what works against them; the model’s own proponents call the human evidence inconclusive.[1]
The good news: the same interventions that help weight management (fasting, exercise, dietary changes) also improve insulin sensitivity.
Further reading:
- Ludwig DS & Ebbeling CB, “The carbohydrate-insulin model of obesity”[4] — JAMA Internal Medicine (2018)
- Sutton EF et al., “Early time-restricted feeding improves insulin sensitivity, blood pressure, and oxidative stress even without weight loss in men with prediabetes”[5] — Cell Metabolism (2018)
- Fung J, The Obesity Code[6] (2016) — On insulin and weight management
Written by AI, directed and approved by me. How this is made →
You already know what to eat
You already know enough.
The information isn’t the problem. You have plenty of information.
The problem is that by the time you’re standing in front of the fridge — tired, negotiating with yourself about whether you’ve earned a snack — it’s already too late. Your habits have voted. Willpower shows up late, outnumbered.
So what if the right thought arrived before all of that?
One thought, every morning, before your day fills in
365 Changes sends you a single prompt about eating. It arrives early — before hunger, before decisions, before habits kick in.
Not a meal plan. Not a rule. Just a question or idea to sit with while you make coffee. Each is simple, but they accumulate.
You need the same core ideas to arrive from hundreds of different angles until they stop being things you know and start being who you are.
Get the daily prompt free:
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Each morning you’ll get a question or scenario like:
You’re in a bad mood and craving comfort food. What do you do first?
Click any of these and read the response — Each one is a complete thought worth reading on its own. The daily email makes sure one arrives before you need it.
- What’s the difference between insulin resistance and insulin sensitivity, and which do you want?
- You don’t have a plan for when you slip up. What will you do next time, specifically?
- How have official dietary guidelines changed over the decades, and why?
Why daily? Why morning? Why small?
Daily, because change doesn’t happen in one big moment of clarity. It happens through accumulation — the same ideas arriving from slightly different angles until one day you notice you’re thinking differently about something you used to not think about at all.
Morning, because evenings are when you negotiate. Mornings are when you can still hear yourself think. There’s a small window before the momentum builds, before the habits wake up. That’s when a thought can land.
Small, because you’ve already heard it all. You don’t need another article, another tip, another list. You need the right ideas to keep showing up until they stick.
This is not a diet program
There’s no tracking. No streaks. No badges. No notifications begging for attention.
If you open the email, good. If you don’t, it doesn’t guilt you. There’s no streak to break. Tomorrow another one arrives.
One email. It asks almost nothing. It just shows up.
Free. No tracking. No streaks. Just one email, every morning.
Does it work?
Honestly? We don’t know if it will work for you.
I built this for myself. I was tired of feeling like I know exactly what I should eat and never quite eating that way. Tired of the mental math — what I ate, what I’ll eat, what I’m going to eat tonight.
I didn’t need more information. I needed the right thought to arrive at the right time. So I built something that does that, every morning, and I started using it.
It’s working. Slowly. I can’t point to a moment when things changed. I just notice that they have.
—Craig
How this gets made is written down too.
The writing here is done by AI. I direct it, and I approve everything before it publishes. Methods is a journal about the work behind the writing: what gets checked, what gets corrected, and what goes wrong. Methods is free, public, and nothing you have to read.
One way to find out:
Want more depth?
Some mornings the prompt will make you curious. The prompt is complete on its own, but each one also has a companion piece — 3 to 5 minutes of depth, grounded in research, for when you want to understand why.
All 500 companions are free to read. Here are four to start with:
- The Future Self — The person you’ll be in five years is being built by today’s choices
- The Food Mood — You’re in a bad mood and craving comfort food. What do you do first?
- The Tolerant One — You can sit with hunger and discomfort without reacting
- The Self-Deception — In what ways do you deceive yourself about what or how much you eat?
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