Sugar causes the overproduction of insulin and weight gain as insulin is a fat-storage hormone that promotes weight gain when elevated.
If losing weight were as simple as counting calories or going on a “diet,” then there would be no issues with losing weight, but there is more to losing weight for the long term that doesn’t involve calorie counting. Losing weight with insulin resistance starts with understanding the connection between sugar and the overproduction of insulin and weight gain.
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According to the work and research of Dr. Jason Fung and his phenomenal book The Diabetes Code, insulin is the primary hormone responsible for weight gain. Elevated insulin levels and insulin resistance are associated with weight gain, so the question that needs to be asked is what causes the overproduction of insulin and weight gain?
Before we dive into how refined carbs and sugar causes weight gain and the overproduction of insulin, let’s first examine the purpose of insulin in the body.
What does the hormone insulin do?
Insulin is a hormone produced by the beta cells of the pancreas and is secreted when blood sugar (glucose) levels rise. The role of insulin is to transport glucose into the cells so glucose can be used as a source of energy once inside the cells. Insulin acts as a key that locks into receptor sites on the cells to allow the entry of glucose from the bloodstream to get inside cells. Without insulin, glucose would not be able to enter the cell. Thus, cell starvation would result.
How does insulin cause weight gain if it is just a hormone that transports glucose?
Insulin causes weight gain by signaling the body to store fat. When insulin levels rise in response to eating food, insulin tells the body not to burn fat because glucose is available in the bloodstream for energy. When blood glucose levels rise, insulin levels rise so that glucose can get into our cells and be stored in the liver and muscles as glycogen for later use. Still, when these stores are full, the liver will convert any excess glucose into fat to maintain normal blood glucose levels.
Insulin causes weight gain as it is the hormone that tells the body to store glucose and not burn fat; thus, insulin can be thought of as your fat-storage hormone. When insulin levels are elevated, the body will be in fat storage mode.
How sugar and refined carbohydrates cause the overproduction of insulin and weight gain?
Refined sugar found in the forms of fruit juice, soda pops, table sugar, and refined carbohydrates such as bread, pasta, pastries, sweet treats, breakfast cereals, chips, and refined grains (flours) are broken down and absorbed at a very rapid pace. The rapid absorption of these foods causes what is known as blood sugar spikes.
The body does not like having a fast release of glucose into the bloodstream; therefore, in response to higher than normal blood glucose levels, the pancreas will secrete higher amounts of insulin to bring blood glucose back to balance. Instead of all those calories providing long-lasting energy, they are quickly stored or turned to fat to restore homeostasis of blood sugar. Sugar causes weight gain by spiking insulin levels, so reducing refined sugar and insulin is crucial to losing weight.
The consumption of refined carbohydrates and sugar often leaves people on an emotional blood sugar roller coaster experiencing energy spikes along with dips and weight gain! These energy spikes and dips are also your body’s initial signs of blood sugar imbalances.
When sugar and refined carbohydrates are eaten continuously, and the body is never given a chance to burn through its glycogen stores in the liver and muscles, the body becomes overwhelmed with the excess glucose.
The cells do not want to take in any more glucose; therefore, they become resistant to the hormone insulin. The cells are screaming, I have enough sugar already, and I do not need any more, so the cells start to become unresponsive to insulin signals.
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How does insulin make you gain weight?
Insulin makes you gain weight by telling the body to store glucose. The glucose storage in fat cells, the liver, and muscles promote increased insulin resistance and weight gain.
The insulin resistance and weight gain problem starts to show once the cells have become unresponsive to insulin signals because the glucose has to go somewhere. So the pancreas pumps out more insulin hoping that more insulin will get that sugar inside the cells so that blood glucose levels lower. But when the cells are consistently unresponsive to the uptake of new glucose, it is converted to fat, resulting in…, you guessed it, weight gain.
The body needs to be given the opportunity to burn through and utilize all the excess glucose that is already in the body to restore insulin sensitivity. The cells will not become responsive and sensitive to the hormone insulin until they need more glucose. To restore insulin sensitivity, you have to stop putting more sugar, refined carbohydrates, and food into the body.
Refined carbohydrates and sugar in all of their many forms are the foods that increase insulin production, thus raising insulin levels and contributing to insulin resistance. So reducing sugar is key to losing weight and reversing insulin resistance. If you need a sugar substitute, stevia, erythritol, and monk fruit extract are the best sweeteners for diabetes. These non-nutritive sweeteners have the least impact on raising blood sugar and insulin levels.
Sugar and refined carbohydrates are found everywhere from commercial breakfast cereals, pop, fruit juice, bread, pasta, sauces, chips, and pretty much everything that comes from a cardboard box. 5 grams of refined carbohydrates equals 1 tsp of sugar. So ditch all the commercial processed foods and get healthy carbohydrates from liver cleansing vegetables.
Eating small amounts of fats will signal the satiety hormones that make you feel full and satisfied while offering a slow-burning source of energy. Be mindful that while fats have the least impact on signaling insulin, they are still energy-dense, and not all fats are equal. Saturated fats directly increase insulin resistance and promote weight gain. Some people need to implement intermittent fasting to restore insulin sensitivity and lose weight.
All food that is eaten will signal the hormone insulin to some degree. In some cases, to restore insulin sensitivity and lower the amounts of insulin present, you must implement more extended periods of fasting (not consuming any food). Fasting allows the body to burn through excess glucose in the body and glycogen stores in the muscles and liver. Cells will be hungry for glucose and responsive to the signals of insulin after fasting.
When practicing intermittent fasting, the glycogen stores will become depleted in the liver and muscles so that glucose has somewhere to be stored temporarily and doesn’t need to be converted into fat for storage.
Why fasting is not the same as calorie restriction
If weight loss were as simple as counting calories, then the answer would be simple, eat less and lose weight. But that is not the case. The body can both raise your metabolism and slow down your metabolism. If a person restricts the number of calories consumed, the body can slow down its metabolism to match the calories consumed.
But, by extending the time period in which no food is consumed, the body will stay in a fat-burning mode allowing you to utilize stored and fat for energy without slowing down your metabolism.
Even if it is just a small amount, any amount of food eaten will trigger the fat-storage hormone insulin. The minute insulin levels rise due to food consumption; you will burn or store the food you just ate.
Losing weight with insulin resistance starts with eliminating/reducing sugar, refined carbohydrates and implementing more extended periods of fasting or practicing intermittent fasting so that you can restore insulin sensitivity and you achieve weight loss. As everyone is unique and may have different degrees of insulin resistance, the fine-tuning of the diet and fasting periods can vary.
While it is important to avoid processed sugar and refined carbohydrates to reverse insulin resistance what is missing from the story is how fats also increase insulin resistance and how a low fat plant based diet is the fastest way to reverse insulin resistance while still eating healthy whole food carbohydrates.
I highly recommend checking out the Mastering Diabetes program and coaching if you want to lose weight and reverse insulin resistance. Their program is revolutionary and effective. It is through following their dietary advice that I was able to manage gestational diabetes and lower my fasting blood sugar.
Supporting your liver with the nutrients it needs to detox along with B vitamins and magnesium to utilize glucose for energy production is a great way to support the liver for weight loss goals. All these nutrients can be found in Metabolic Detox Complete.

Found this information amazing and know some friends who can benefit from this.
Thanks Elizabeth, I’m glad you found the information helpful:)
Really nice and interesting post
Thanks Lucy, I’m glad you enjoyed reading it and found it interesting:)
Thank you so much! Such a helpful write-up
This was actually super informative and helpful, and explains in a very simple and clear way! Thank you!
Your welcome! I’m so glad you found the article helpful and easy to understand:)
Hello, I cannot do any fasting because my Adrenals are shot and I can’t put more stress on them. But I have cut out simple sugars and starchy carbs from my diet for 2 months now because I believe I was insulin resistant…BUT I haven’t experienced ANY weight loss. How long until my body starts losing weight? I’m starting to lose hope as I’ve only been eating high quality animal protein and organic vegetables for 60 days but not seeing any results. I’m wearing a CGM tracker and my Blood Sugar is very low, average of 80, never going above 120 and I’m still not seeing ANY weight loss. HELP!
Thanks for sharing your story. Yes that’s frustrating but there are many additional underlying causes of an inability to lose weight such as food sensitivities and fatty liver. Fruits are among some of the best foods for weight loss and animal products are high in saturated fats that increase insulin resistance and the risk of developing fatty liver. What happens to you blood sugar when you eat natural sugars in whole fruits? If you cant tolerate fruits without your blood sugar spiking out of the normal range then this is a sign that you are still insulin resistant. Mastering Diabetes has another approach to insulin resistance that many people are unaware of.