Does Insulin Really Make You Fat? The Facts vs. the Myths

There's a common narrative that insulin is the ultimate culprit in weight gain. According to the “Carbohydrate-Insulin Model of Obesity,” eating carbohydrates causes a surge in insulin, leading to fat storage, hunger, and ultimately weight gain. But is this theory as sound as it appears? Let’s delve into the details and see if insulin is really making you fat, or if there’s more to the story.

The Carbohydrate-Insulin Model Explained

The theory argues that when we consume carbs, our bodies release insulin to manage blood sugar levels. Insulin then promotes fat storage, as it shuttles nutrients from the bloodstream into cells. As blood sugar levels drop, hunger increases, causing us to eat more and perpetuate a cycle of overeating and fat storage. The end result, some claim, is dramatic weight gain, with insulin as the key player.

There’s some truth here: insulin indeed plays a role in storing fat. However, this theory leaves out crucial details, especially when it comes to how insulin functions in the body.

The Real Role of Insulin

Yes, insulin does promote lipogenesis, the process of creating and storing fat. But insulin doesn’t just feed fat cells; it also feeds muscle cells and helps with muscle growth and repair. Importantly, the process of storing fat cannot occur without a calorie surplus. In other words, you need to consume more calories than you burn to gain fat, regardless of insulin levels.

People on both high-carb and low-carb diets can gain or lose weight. What matters most is the overall calorie balance. Research has shown that, as long as calorie intake is the same, weight gain does not significantly differ between high-carb and low-carb diets.

Are Low-Carb Diets the Solution?

Many turn to low-carb diets to minimize insulin spikes, replacing carbs with fats. However, dietary fat can easily be stored as body fat. When people consume high-fat diets in excess, this fat is directly stored without the need for conversion, which is a more efficient path to fat gain than carbohydrates. Additionally, fat is slightly more lipogenic than carbs, meaning it can promote fat storage more readily.

The Truth About Hunger and Insulin

One misconception is that insulin spikes drive hunger. While exogenous insulin (like insulin injections) can increase hunger, endogenous insulin (naturally produced in the body) often promotes satiety. If insulin’s role was solely to make us ravenous, then high-carb diets would always lead to increased hunger and overeating, but real-world studies show this isn’t the case. In fact, insulin release after a meal often contributes to a sense of fullness.

The Most Lipogenic Foods Aren't High in Carbs

Foods most associated with fat gain are not necessarily high-glycemic or insulin-inducing. Instead, highly processed foods like pizza, ice cream, and cookies—which combine fats and sugars with a high-calorie density—are the biggest culprits. These foods are low on the glycemic index, meaning they don't cause major insulin spikes, yet they are among the most lipogenic because they are calorie-dense and highly palatable, making it easy to overconsume.

Why Do These Myths Persist?

People often seek simple explanations for complex problems. Blaming insulin allows people to sidestep the need for dietary moderation and portion control. Instead of focusing on the amount and quality of food, they fall into the trap of thinking that simply reducing carbs or avoiding certain food groups will prevent weight gain. But the science tells us that weight gain is more about the overall balance between calories in and calories out.

So, What's the Real Takeaway?

The idea that insulin alone is responsible for weight gain is an oversimplification. While insulin is involved in fat storage, it’s only one piece of a larger puzzle that includes calorie intake, physical activity, and overall diet quality. If you focus on a balanced, nutrient-rich diet while managing calorie intake, you can maintain a healthy weight without obsessing over insulin spikes.

Are you interested in taking control of your health and understanding the real factors that influence weight management? At Brooktree Consulting, I go beyond simplistic myths and offer a personalized approach to wellness. Whether you’re looking to lose weight, build muscle, or improve your overall health, I can help you find a sustainable plan that works for you. Ready to get started? Schedule a discovery call with me today and start your journey towards a healthier you!