---

In the late 2000s, Janice Hwang was a young resident at Beth Israel Deaconess Medical Center in Boston, where she encountered a patient with a condition every textbook said was treatable: type 2 diabetes. Their body was not responding to insulin — the hormone that helps deliver sugar to cells for energy — causing sugar to build up in the bloodstream.

No matter how carefully Hwang adjusted her patient’s insulin regimen or explained the importance of monitoring blood sugar, their numbers never improved. Then one day, the patient admitted they were afraid of taking their medication. The treatment regulating their blood sugar actually made them feel shaky and dizzy.

Years later, Hwang would learn that this patient’s experience wasn’t imagined — or uncommon. Their brain had adapted to chronic high blood sugar. What felt “normal” to their body was dangerously elevated to everyone else.

That realization humbled her.

“If I had known then what I know now, I would have spent less time lecturing and more time listening,” she admits.

Today, as chief of the Division of Endocrinology and Metabolism at UNC-Chapel Hill, Hwang explores this feedback loop, investigating how the brain interprets signals from the body and, in turn, shapes the body’s response. By tracing this dialogue, she hopes to better understand how miscommunication between the two may drive metabolic diseases like diabetes and obesity.

Science driven by care

Hwang began studying medicine in 2001 at Harvard Medical School, driven by the same goal as many other young physicians: a desire to cure cancer.

But during her residency, she noticed that nearly every patient she treated, regardless of their diagnosis, had some form of metabolic disease.

Her observation reflected a staggering reality. Today, 1 in 10 Americans has diabetes, and nearly half meet the criteria for obesity. These conditions increase the risk of heart disease, stroke, and cognitive decline — and together account for more than $400 billion in medical expenditures. 

Even when metabolic disease wasn’t the main reason for hospitalization, it shaped every aspect of care. So, Hwang shifted her gaze away from cancer and toward metabolism, focusing instead on how our body uses and stores energy, processes that fall within the scope of endocrinology.

“It’s the field for people who want to understand how the different organs communicate and how the whole body works as a system,” she says with a smile.

In endocrinology, Hwang also found fertile ground for research. In 2012, she moved to Yale University to start a research fellowship under the guidance of Robert Sherwin, a pioneer in metabolism research and one of the inventors of the insulin pump.

First developed in the 1970s, the device transformed diabetes care. It started off the size of a backpack; now it fits inside a pocket — delivering a steady stream of insulin, which gives people unprecedented control over their blood sugar and freedom from the rigid routines of daily injections.    

“Bob was the perfect example of a physician-scientist,” Hwang recalls. “He took what he learned from experiments in the lab and brought it right back to his patients.”

It’s a balance Hwang strives to emulate in her own work — shifting between treating patients and managing a lab, letting each one inform the other.

As a physician, she specializes in diabetes but treats cases spanning the full spectrum of endocrinology. As a researcher, she uses advanced neuroimaging tools to understand how metabolic conditions like diabetes affect the brain — and how the brain influences the body.

The ultimate feedback loop

In studying the brain, Hwang is taking a slightly unconventional approach for an endocrinologist. Traditionally, the liver and pancreas have been the central characters in the story of metabolism. They are responsible for producing, storing, and regulating hormones like insulin and sugars like glucose, the body’s main source of energy.

But these organs don’t act independently. The brain serves as the control center orchestrating their actions. When blood sugar rises after a meal, the brain signals the pancreas to release insulin. When levels dip, it cues hunger and prompts the liver to release stored glucose.

The brain also weaves in other, seemingly unrelated, signals about stress, sleep, and body weight to adjust metabolism.

“It’s the ultimate feedback loop,” Hwang explains. “The brain takes all these signals from the periphery — nutrient signals, weight signals, stress signals — integrates them and feeds them back out to control the rest of the body.”

In healthy people, rises in blood sugar trigger a proportional change in the brain. Hwang’s research shows that in obesity and diabetes, the fidelity of this communication starts to break down or becomes blunted.

“Glucose is one of the cues that tells your brain you’ve eaten enough,” Hwang says. “A weaker signal might mean the message never fully gets through.”

The muted perception of the body’s state may, in turn, contribute to increased hunger and difficulty regulating weight.

Hwang’s research reframes not only how physicians approach treatment, but also how society views metabolic conditions like obesity, which have historically carried a heavy social burden.

“Obesity is often viewed as a failure of willpower,” Hwang says. “But it’s not just about controlling what you eat and how much you exercise.”

By mapping the intricate relationship between the brain and metabolism she shows it’s not simply a behavioral problem — it’s a biological one.

When metabolism talks back

Hwang believes that understanding how the brain coordinates metabolism could open new doors for treating a range of metabolic conditions. But the bridge between brain and metabolism runs both ways.

Changes in metabolism can alter the brain’s structure and function, especially early in life, when it’s most responsive to shifts in its internal or external environment. This is particularly relevant for type 1 diabetes, when the immune system mistakenly attacks and destroys insulin-producing cells, causing large and frequent fluctuations in blood sugar.

“Some kids diagnosed with type 1 diabetes thrive, while others go on to experience cognitive and emotional challenges later on,” Hwang says.

Understanding why some children are more vulnerable than others is one of the central questions driving her current work. Her lab is part of BRAINY-T1D, a multi-site study funded by the National Institutes of Health that follows children diagnosed with type 1 diabetes over several years to examine how the condition shapes brain development.

The study involves 11 sites across the country, combining advanced brain imaging with mental and social tests to uncover what makes some people resilient and others vulnerable, questions that echo across her broader work.

For Hwang, the connection between science and care is as dynamic as the one between brain and body. Each patient encounter offers insights that shape her research questions, and each experiment deepens her understanding of the human stories behind the data.

“Working with people is great because of the relationships you develop,” she says. “You can teach them about their disease, and they can teach you about their experience.”