A ‘Vicious Cycle’ -- Insulin Resistance and Weight Gain

Changes in the body that most people don’t notice are underway long before a person is diagnosed with type 2 diabetes. Insulin resistance is the most vital change. Unfortunately, since there are usually no symptoms, you won’t know you have insulin resistance. But there’s good news: You can prevent or delay it if you’re at risk.

Insulin resistance is often accompanied by weight gain – but one does not cause the other, explains Pascual De Santis, M.D., an endocrinologist at Baptist Health South Florida.

Pascual De Santis, M.D., an endocrinologist at Baptist Health South Florida.

Insulin is a hormone made by the pancreas that helps glucose in the blood enter cells in your muscle, fat, and liver, where it’s used for energy. Glucose comes from the food you eat. The liver can also makes glucose in times of need, such as when you’re fasting. When levels of blood glucose, or blood sugar, increase after you eat, your pancreas releases insulin into the blood. Insulin then lowers blood glucose to keep it in the normal range.

Insulin resistance is when the cells don’t respond well to insulin and can’t easily take up glucose from your blood. As a result, the pancreas makes more insulin to help glucose enter the cells.

“What causes insulin resistance is a difficult question to answer because it’s not really well understood,” said Dr. De Santis. “We know it is an interaction of a genetic predisposition with environmental factors or lifestyle habits (poor diet and lack of exercise) that allow the insulin resistance or the genetic predisposition to flourish. And the modifiable factor that has intimately been linked to insulin resistance is obesity.”

Insulin resistance usually doesn’t cause symptoms until the person develops diabetes, says Dr. DeSantis, who recently spoke extensively on the topic on the TB Media Group podcast.

“For example, somebody who’s gaining weight cannot say, ‘Well, I’m gaining weight because I’m insulin resistant.’ No. You are gaining weight in parallel to the development of the insulin resistance,” he explains. “It’s happening together and it’s a vicious cycle. The more weight you gain, the more insulin resistance you have. And the more insulin resistance you have and the higher insulin levels, the more weight you gain.”

Prediabetes — a condition fueled by insulin resistance that if left unchecked often leads to type 2 diabetes — is so common that U.S. public health officials often attempt to boost awareness about this relatively silent epidemic. 

In the U.S., more than 1 in 3 adults are believed to be living with prediabetes, and more than 80 percent don’t even know they have it. Prediabetes can increase a person’s risk of developing type 2 diabetes, heart disease, and stroke.

How long would it typically take insulin resistance to develop?

“That would be very dependent on each individual, each life, each history, each lifestyle, each genetic background,” says Dr. De Santis. “That’s a difficult question to answer. But this is something that usually happens over many years.”

How do you find out if you’re insulin resistant? There’s no single test that diagnoses this condition. But getting your routine blood work with your primary care physician is crucial in the process of reaching a diagnosis. If you have high blood sugar levels, high triglycerides (a kind of blood fat), high LDL (“bad”) cholesterol, and low HDL (“good”) cholesterol, your health care provider may determine you have insulin resistance. And if you are overweight or obese, the risk of insulin resistance increases significantly.

“So, the more weight you gain, the more insulin resistant you become and therefore the higher the insulin levels that you’re going to have — which is going promote more fat deposition and so on,” said Dr. De Santis. “With that type of snowball effect, it’s going to be much more difficult to reverse it the later you catch it.”