Does Insulin Cause Weight Gain?

If you’ve been experiencing unwanted weight gain and struggling to find the root cause, you may be surprised to learn that your insulin levels could partially be to blame.

Insulin is an often misunderstood hormone that plays an important role in allowing your body to use glucose for energy. But having too much of it has been associated with weight gain, insulin resistance, and hyperinsulinemia. 

Finding yourself stuck in a pesky weight loss plateau or noticing the number on the scale rising despite all your efforts can be frustrating. So, could high insulin levels be part of the reason why?

Read on for the full breakdown on insulin and weight gain, plus some effective tips to support healthy insulin levels and sustainable weight loss.  

What is Insulin?

Insulin is categorized as an anabolic hormone in the body. It can stimulate various growth-related pathways, including the storage of glucose as glycogen and the storage of fat.

Insulin can influence the brain and is associated with cognition and memory processing, among other functions. It also supports muscle growth, cell repair, and other building functions.

While it is important to assure we do not always have high levels of insulin circulating, normal insulin levels help regulate your blood sugar levels. Here’s how it works:

• Blood glucose levels rise after you eat, prompting your pancreas to release insulin into the blood.
• Insulin directs the body to use the blood glucose for energy or store it in the liver or muscle tissue as glycogen for future use.
• This is what allows your body to keep glucose levels in the normal range.

Although key components involved in insulin signaling are present in almost every cell, there are a few “classic” areas that host a lot of insulin-related action. These areas are the liver, skeletal muscles, and fat or adipose tissue.

What is Hyperinsulinemia?

Hyperinsulinemia means having chronically high levels of insulin. Some studies have suggested that high insulin levels may be present years before diabetes develops. 

The amount of insulin that your body needs in circulation may depend on the person, and there isn’t yet a scientific consensus on optimal insulin levels. However, studies suggest that normal fasting insulin levels are anything less than 25 mIU/L. 

Some experts believe the optimal threshold should be lower, though more research is needed. While it’s important for the body to have enough insulin to store glucose in the body and complete other functions, high levels of insulin is strongly associated with type 2 diabetes. 

According to current research, addressing hyperinsulinemia may support optimal metabolic health. High insulin can be a risk factor for metabolic health conditions such as:

• Obesity and weight gain
• Heart disease
• Cancer
• Fatty liver disease 
• Cognitive decline

Insulin and Weight Gain

Hyperinsulinemia is associated with insulin resistance and weight gain. This is because when cells are constantly exposed to high insulin levels, they may start to “ignore” the effects of insulin.

The glucose then remains in the bloodstream and this can lead to elevated blood glucose levels. In this case, even though there is plenty of insulin available, your body may not respond to it, aiding in an environment of insulin resistance.

So how does this cause weight gain?

• Because the glucose never leaves the blood, the pancreas never flips the “off switch.” 
• Your pancreas continues to produce higher amounts of insulin. 
• Your body may respond by slowing fat breakdown and promoting fat storage.

High blood insulin levels also signal the sensation of hunger, resulting in increased food intake and increased sugar cravings. It is a vicious cycle that can be hard to break.

A combination of genetic factors, dietary and lifestyle factors may all contribute to hyperinsulinemia. Some researchers suggest that early treatment of the hyperinsulinemia that precedes metabolic dysfunction may successfully treat obesity and prevent complications.

If you take insulin injections for diabetes, weight gain is a common side effect. Make sure to always talk to your healthcare provider if you are experiencing any suspected side effects of prescribed medications.

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What Causes Hyperinsulinemia?

As we mentioned, there are a number of potential causes of hyperinsulinemia. Environmental, genetic, and socioeconomic factors can all contribute to the development and progression of this condition.

Fasting insulin levels are determined by the balance between insulin secretion, insulin sensitivity, glucose tolerance, and insulin clearance, each of which may have different determinants. 

Let’s take a look at each of the factors that may drive hyperinsulinemia.

1) High Blood Glucose Levels 

Having chronically high blood sugar levels, or hyperglycemia, can lead to excess insulin being released into the body. Dietary factors, lack of physical activity, and high stress levels (which may include a lack of sleep) are all things that can lead to chronically high glucose.

2) High Free Fatty Acid Levels in the Blood 

Research has shown that high levels of fatty acids can lead to insulin resistance. People who are overweight or obese tend to develop both elevated levels of free fatty acids and insulin.

3) Dietary and Environmental Factors

Dietary and environmental exposures may stimulate hypersecretion of insulin under fasting conditions. This can lead to hyperinsulinemia.

Interestingly, air pollution has been associated with adverse lipid changes and higher fasting glucose and insulin. It is also linked to higher childhood body mass index (BMI) trajectories. 

4) Ethnicity and Genetics

Hyperinsulinemia may have certain ethnic and genetic predispositions, meaning that people with certain ethnicities and genes may be more susceptible to developing this condition. 

Who is at Risk for Hyperinsulinemia?

People who have or are at risk for prediabetes or type 2 diabetes mellitus may also be at higher risk of developing hyperinsulinemia. This may be because hyperinsulinemia may lead to the development of obesity as well as the beta-cell dysfunction that can lead to type 2 diabetes.

Those with insulinoma, which is a type of benign tumor caused by the hypersecretion of insulin, may also have an increased risk of developing hyperinsulinemia. Insulinoma can lead to hypoglycemia, or low blood sugar levels.

There is often a connection between insulin resistance and hyperinsulinemia. Hyperinsulinemia is what leads to insulin resistance and “feeds” it, leading to a vicious cycle of poorer insulin and glucose regulation over time.

In fact, scientists believe that the link between the following processes are all so strongly intertwined that hyperinsulinemia on its own may be enough to cause the others to occur:

• Hyperinsulinemia
• Insulin resistance
• Impairment of glucose-stimulated insulin release 

So what can you do to prevent this condition? If you are concerned that higher insulin levels may be leading to weight gain, here are a few things you can implement into your routine:

4 Ways to Support Healthy Insulin Levels Starting Now

Now that you understand the link between insulin levels and weight gain, you may be wondering what the best ways to support healthy insulin levels are. While there are strategies to improve your insulin levels, the “best” ways will vary as your body is unique.

Always work with your doctor/qualified healthcare team to find the right solutions for you! Seeking personalized guidance from a dietitian is also a good idea. 

1) Limiting Refined and Processed Carbohydrates 

Refined carbohydrates often have a higher glycemic index, or GI, which can negatively impact your insulin sensitivity. Studies have shown that a high GI diet is strongly associated with insulin resistance, especially over a long period of time

Limiting your carbohydrate intake to unrefined, whole food sources can help to support healthier insulin levels. Better yet, pair your low GI carbs with additional fiber and protein.

2) Finding the Right Macronutrient Breakdown For Your Unique Body

In addition to limiting refined carbohydrates, you may want to explore the optimal breakdown of macronutrients for your dietary needs. This can mean trying out different types of carbs, proteins, and fats by creating a meal plan with foods such as legumes, whole grains, and root vegetables.

As we discussed, glucose levels and insulin are closely linked, so finding your glucose tolerance can also support healthy insulin levels. Blood sugar monitoring with a tool like a continuous glucose monitor, or CGM, can be one way to find this.

A CGM can provide you with glucose data that you can use to find your glucose tolerance, and optimize your diet and overall wellness.

3) Incorporating Resistance Training Into Your Routine

Exercise, especially resistance training, has been shown to support healthy insulin levels. Resistance training involves doing intense exercise in short bursts and comes in many forms and can range from weight lifting, or cardio, functional training, or a mix of all three.

Not only can exercise help with weight management and maintaining a healthy body weight, it can support healthy glucose levels and even boost your mood.

You can experiment with the different types of exercises and find ones that work for you. 

4) Building Healthy Habits

In addition to incorporating exercise, there are other beneficial lifestyle changes you can implement that will help support healthy insulin levels. For example, studies show that higher levels of insulin may be a result of higher oxidative stress load in the body.

Some healthy habits for optimal metabolic health include:

• Meeting nutrient needs including optimal vitamin and mineral intake
• Not under or overeating
• Getting enough sleep 
• Managing other sources of stress 
• Supporting your body’s antioxidant functions