Why weight is hard to lose with insulin resistance and how to decide on meal timing
With insulin resistance, insulin stays high, fat is stored more easily and hunger signals come more often. Our book gives two ways to give insulin a rest: intermittent fasting and regular meals. Intermittent fasting is not advised for people with diabetes or a tendency to low blood sugar, and people who skip meals and then eat a lot at once are advised to eat regularly every three hours. Supplements have limited effect; the groundwork is meals, muscle and sleep.
- ACADEMYSenior Academic Director, Korean Academy of Dermatology, Obesity and Plastic Surgery (KACS)
- PROFESSORAdjunct Professor, Korea University Medical Center
- FELLOWSHIPFellowship, University of Florida Shands Hospital
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- Ewha Womans University College of Medicine
- Residency, Korea University Medical Center
- Adjunct Professor, Korea University Medical Center
- Fellowship, University of Florida Shands Hospital
- Senior Academic Director, Korean Academy of Dermatology, Obesity and Plastic Surgery (KACS)
Contents6
- 01Why weight is hard to lose once insulin resistance sets in
- 02Signs that suggest insulin resistance and when tests are suggested
- 03How to choose between intermittent fasting and regular meals with insulin resistance
- 04Meal order, strength training and sleep for reducing insulin resistance
- 05Why to keep expectations low for supplements such as berberine
- 06Frequently asked questions
Some people tell us they have cut down on sweets but their waist has not changed, and they get very sleepy after lunch. The first chapter of the book I co-wrote, Eat to Succeed (a Korean-language book, 2026), explains this picture as insulin resistance.
Why weight is hard to lose once insulin resistance sets in
Eat a doughnut and your blood sugar rises, so the pancreas releases insulin. Insulin works like a key that lets sugar into cells, and once the cells take it in, blood sugar settles back down. But if you have bread, biscuits and fizzy drinks every day, blood sugar goes up and down like a roller coaster and cells gradually stop responding to insulin. The book puts this in the cells' own words.
"Insulin again? Can't be bothered. Ignore it!"
Because the cells do not respond, the pancreas sends out even more insulin. Insulin resistance is this state, where insulin rises but the body does not respond. When insulin stays high, more fat is made and less is broken down, and it tends to collect around the abdomen as visceral fat. When sugar cannot get into cells, the brain reads it as an energy shortage and keeps sending signals to eat. That is why you can eat less and still get hungry easily and keep your belly fat.
The book also describes a loop that does not stop there. Obesity brings inflammation, and that inflammation makes insulin resistance worse. Extra fat tissue itself releases inflammatory substances, so the loop is hard to break.
Signs that suggest insulin resistance and when tests are suggested
Some people find their eyelids getting heavy about two hours after lunch and keep reaching for something sweet even when they are not hungry. Chapter 1 of the book lists the signs of insulin resistance like this.
- Strong sleepiness about two hours after a meal
- Wanting to eat even when not hungry, with strong cravings for sweet things
- Weight gathering around the navel
- Darkening skin on the back of the neck
- Energy going up and down like a roller coaster through the day
Having one of these does not mean we suggest tests for everyone. Looking at your overall health does not mean recommending tests to every patient. We suggest the tests you need only when your symptoms and medical history give a reason to check.
Sometimes blood sugar comes out high even in people who hardly eat sweets. Chapter 6 of the book explains that lack of sleep lowers insulin sensitivity, and that a high level of the stress hormone cortisol raises blood sugar and makes insulin resistance worse. In other words, changing your diet alone may not be enough.
How to choose between intermittent fasting and regular meals with insulin resistance
The book describes two ways to give insulin a rest: intermittent fasting, which leaves long gaps without food, and regular meals, eating small amounts every three hours. They look like opposites, but they suit different people.
| Group | What the book describes |
|---|---|
| People who can try intermittent fasting | Have insulin resistance and cope with long fasts without difficulty · freelancers or people working from home with flexible schedules · prefer simple rules such as "eat during these hours, not during those" |
| People for whom intermittent fasting is not advised | Diabetes, a tendency to low blood sugar or hypoglycaemia · high stress · skipping dinner leaves them too hungry to sleep · a history of eating disorders · pregnancy or breastfeeding · growing teenagers · high-intensity athletes · jobs that need constant concentration such as surgeons, pilots or drivers |
| People advised to eat regular meals | Skip food in the morning and then eat a lot at lunch or dinner · get shaky, irritable and unable to concentrate when fasting goes on too long |
If you go without food for a long time and then eat a lot at once, blood sugar shoots up, insulin floods out and the leftover energy is stored as fat. When blood sugar then drops, strong hunger returns and you go looking for food again. That is why we suggest regular meals to people who eat this way. Eating regularly keeps blood sugar steady, so insulin is released in moderation. If you already eat three regular meals a day and do not binge, though, there is no need to split your food into five times a day.
If you have started intermittent fasting, let your body's response decide whether to keep going. The book says that if you feel tired, irritable, unable to focus or start binge eating, the method does not suit you. If you feel refreshed, focus well and find it easy to control your meals, you can carry on.
Meal order, strength training and sleep for reducing insulin resistance
It is easy to think only of swapping white rice for brown rice, but the book covers meals, muscle and sleep together.
- Cut refined carbohydrateseat less white rice, white bread, biscuits and fizzy drinks, and get more fibre from vegetables, whole grains and beans.
- Eat vegetables firsteating vegetables, then protein, then carbohydrates makes blood sugar rise more gently.
- Strength trainingmuscle uses a lot of sugar, so strength training should not be left out.
- Sleeplack of sleep makes insulin resistance worse, so get enough of it.
A small study has looked at sleep and blood sugar. It compared 11 healthy young men after six nights with only four hours in bed and after six nights of recovery with 12 hours in bed. When short of sleep, their bodies handled glucose less well and their evening cortisol was higher. With only 11 participants, the result cannot simply be applied to everyone.
There is also a study that followed lifestyle change over several years. It took 3,234 people who did not have diabetes but had high fasting blood sugar and high blood sugar after a glucose load. The group that changed their lifestyle, aiming to lose 7% of body weight and to be active for at least 150 minutes a week, developed diabetes 58% less often than the placebo group over an average of 2.8 years. What the study compared was whether people developed diabetes, not methods of losing weight.
Why to keep expectations low for supplements such as berberine
You will often hear the names of supplements said to be good for blood sugar. Chapter 7 of the book notes that there are studies suggesting supplements such as berberine, curcumin and resveratrol improve blood sugar and insulin sensitivity, but that their effect is limited. Even if you take them, they cannot replace changing your meals, muscle and sleep.
Chapter 1 also says that topping up magnesium and chromium helps improve insulin sensitivity. That means filling a shortfall, not that taking more is better.
Once you have chosen an approach, what comes next is time. In the words of the book: "Any method is fine, but keep it up for at least three months. Once it becomes a habit, nothing is more powerful."
Frequently asked questions
QCan you lose weight with insulin resistance?
When insulin stays high, fat breakdown is held back and the brain, sensing an energy shortage, sends hunger signals more often, so weight can be hard to lose. The book suggests cutting refined carbohydrates, eating vegetables first, and changing strength training and sleep at the same time.
QDoes intermittent fasting help insulin resistance?
People who cope with long fasts without difficulty can try it. It is not advised if you have diabetes or a tendency to low blood sugar, a history of eating disorders, are pregnant or breastfeeding, or do work that needs constant concentration. For people who skip food in the morning and then eat a lot at once, we suggest regular meals every three hours.
QDoes everyone need a test for insulin resistance?
We do not suggest it for everyone. We suggest the tests you need only when your symptoms and medical history give a reason to check.
QAre there supplements that help insulin resistance?
There are studies suggesting supplements such as berberine, curcumin and resveratrol improve blood sugar and insulin sensitivity, but their effect is limited. They cannot replace changing your meals, strength training and sleep.
QCan lack of sleep cause insulin resistance?
Lack of sleep lowers insulin sensitivity. In a study of 11 young men kept to four hours in bed for six nights, their bodies handled glucose less well than after enough sleep.
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