What do diabetes, obesity, chronic kidney disease, liver disease, cardiovascular disease, and even some cancer have in common? They are all metabolic conditions – sometimes caused, or worsened by poor metabolic health. And critically, these diseases often can be improved or even reversed by changing what you eat.
What exactly is metabolic disease, and why is it at the center of so many chronic ailments?
Metabolism is how we deconstruct food into energy, building blocks for our human systems, and waste products, and build and store what our body needs. When that process doesn’t run smoothly, we call it metabolic disease. At the core is the body’s development of resistance to insulin – the glucose-regulating hormone – and the result is abnormal insulin levels, as well as unhealthy fat storage. And it turns out that abnormal metabolism reaches beyond conditions we typically associate with diet.
For generations, we thought of diabetes as THE metabolic disease. But it turns out that so many other conditions have a metabolic root cause – and by extension, a metabolic root cure. Cardiovascular disease and chronic kidney disease, for example, were always more common in patients with diabetes – but it wasn’t until the American Heart Association recognized the cardiovascular-kidney metabolic (CKM) syndrome in 2023 that clinicians aligned behind this concept. The same is true of metabolic dysfunction–associated steatohepatitis (MASH), a liver disease driven by poor metabolic health that was only renamed in 2023 – underscoring how recently the field has begun connecting these dots.
Similarly, scientists have always known that diabetes is a risk factor for some cancers, but the idea of cancer having a metabolic component is somewhat new. We think of cancer as a disease of genetic mutations leading to unchecked cell growth – tumor cells replicate and expand until they damage the surrounding tissue and spread throughout the body. What’s less well understood is why cancer is more likely in patients with metabolic disease – obesity and diabetes. One theory is that inflammation caused by metabolic disease contributes to cancer’s growth and spread by impairing the body’s ability to detect and repair abnormal cells; another theory is that some cancer cells thrive on high levels of glucose and insulin – two components of metabolic disease. Clinical research exploring dietary intervention in oncology has begun to test these concepts.
Why is this? Does a low-carbohydrate diet starve cancer cells of sugar – their preferred source of energy? Does a low-carbohydrate diet reduce the amount of inflammation in the patient’s system, or change tumor signaling pathways, somehow reducing cancer cell growth? It’s not entirely clear. But sometimes what matters is the results, not the mechanism.
The common mechanism for reversing metabolic disease seems to be the sustained flattening of the hills and valleys of glucose and insulin. Consider a breakfast bagel: it’s quickly converted to glucose in the intestine, blood glucose levels rise, insulin spikes in order to move that glucose into cells, and pretty soon blood glucose falls. When liver and muscle glucose storage is full, additional glucose is converted to fat, contributing to body fat stores and obesity, including abnormal fat accumulation around the abdominal organs causing organ dysfunction. Excess body fat drives inflammation which is a key component of insulin resistance.
When breakfast is a couple of eggs (entirely protein and fat), the cycle never starts. Over a few days, the liver starts to metabolize fat, and glucose levels (also produced by the liver) stay relatively constant, as do insulin levels. This is how metabolic disease is reversed.
Photo: fcafotodigital, Getty Images
Adam Wolfberg, MD, MPH, is the Chief Medical Officer at Virta Health. Previously, he was the CMO at Current Health (acquired by Best Buy) and Ovia Health (acquired by LabCorp). Before that, he worked in medical affairs at athenaHealth and Ariosa Diagnostics (acquired by Roche). Adam trained in OB/GYN and maternal-fetal medicine and practices at Cambridge Hospital. Before going to medical school he was a print journalist. He blogs at www.adamwolfberg.com, and has written for magazines and websites including the Boston Globe Magazine, Slate.com, Huffington Post, and WSJ.com. His first book, Fragile Beginnings, was published by Beacon Press in 2012.
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