Decoding Metabolism and Why When You Eat Matters with Joseph Bass, MD, PhD

Disrupting our internal clocks can lead to diseases such as obesity and diabetes. Scientists at Northwestern have uncovered the mechanism behind why late-night eating is linked to weight gain and diabetes. Joseph Bass, MD, PhD, led the study published in the journal Science in fall 2022. In this episode, he shares the results and details the two decades of work leading to this latest discovery. 

Since this episode was released Dr. Bass has led several other studies looking at circadian rhythms and weight loss. Most recently, his team published in the Proceedings of the National Academy of Sciences about an experimental RNA therapy that induces the body to burn calories and preserving lean mass, thereby enhancing the benefits of GLP-1s.

“...The time that an animal eats influences its body weight, and it does so through a mechanism that must involve the intrinsic timing system, and that was a problem that we set out to address many years ago. This feedback from the diet to the clock, how does this happen and what are the regulators of this connectivity between clocks and diet.” — Joseph Bass, MD, PhD

  • Director, Center for Diabetes and Metabolism 
  • Chief of Endocrinology in the Department of Medicine 
  • Charles F. Kettering Professor of Medicine 
  • Professor of Medicine in the Division of Endocrinology 
  • Member of Northwestern University Clinical and Translational Sciences Institute  
  • Member of the Robert H. Lurie Comprehensive Cancer Center 

Episode Notes 

Scientists at Northwestern Medicine were the first to understand at the gene level why disrupting our internal clocks can be linked to weight gain and diabetes and how energy release may be the mechanism through which our internal clocks control energy balance. 

  • Bass says our contemporary understanding of circadian rhythms originated via an observation in plants by Jean-Jacques d'Ortous de Mairan, a French biologist in the 18th century, placed a mimosa plant in a dark box and showed that the leaf opening and closing of the plant continued even in constant darkness. This was the first evidence for an internal intrinsic process that enables all photosensitive organisms to anticipate the daily rising and setting of the sun. 
  • He arrived at Northwestern University Feinberg School of Medicine during a time when investigators there were exploring a breakthrough understanding between genes that program the regulation of sleep-wake cycles as well as circadian cycles, and processes that regulate endocrine systems. This became a launching pad for the next 20 years of Bass’ work. 
  • The questions that Bass and his colleagues wanted to address emerged within early studies showing that animals whose sleep-wake cycles are aligned with the rotation of the earth are prone to develop obesity as well as a broad range of other additional metabolic problems when the circadian clock is broken. This led to insights into the purpose of the clock beyond its role as a regulator of behavior. 
  • Bass and his colleagues also discovered that circadian clocks, although they are intrinsic and cause us to awake each day, are sensitive to our dietary environment, and furthermore, that the time an animal eats can influence its body weight. This was a problem Bass set out to address many years ago: this feedback loop between diet and clock. 
  • In their research on why eating late at night is linked to weight gain and diabetes, Bass and his team used a set of genetic tools to ask whether the energy burning capacity in the body of animals exhibits a circadian pattern, or in other words, whether the capacity to store or burn food varies according to the light-dark cycle. 
  • These findings have broad implications for public health. For example, patients who are fed with feeding tubes almost always develop very severe insulin resistance and abnormalities of metabolism, possibly due to a violation of the environmental day-night cycle which may give rise to a range of pathologies or disease. 
  • Bass describes this bidirectional relationship between timing and both light and nutrients as fundamental, and deepening this research could lead to a profound understanding of how genes are regulated in a rhythmic fashion, both within neurons in the brain to control behavior, and in tissues in peripheral organs to regulate functions such as energy dissipation. 
  • Ultimately, Bass hopes that this work will stimulate people from a wide range of fields to incorporate these insights into the context of other diseases. 

Additional reading 

  • Browse all of Bass’ publications  
  • Read the Northwestern University press release about the Science study 
  • Find out more about the 2017 Nobel Prize in Physiology or Medicine, awarded jointly to Jeffrey C. Hall, Michael Rosbash and Michael W. Young for their discoveries of molecular mechanisms controlling the circadian rhythm. 

Recorded February 1, 2023. 

Re-released on October 12, 2026.

Continuing Medical Education Credit

Physicians who listen to this podcast may claim continuing medical education credit after listening to an episode of this program.

Target Audience

Academic/Research, Multiple specialties

Learning Objectives

At the conclusion of this activity, participants will be able to:

  1. Identify the research interests and initiatives of Feinberg faculty.
  2. Discuss new updates in clinical and translational research.

Accreditation Statement

The Northwestern University Feinberg School of Medicine is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians.

Credit Designation Statement

The Northwestern University Feinberg School of Medicine designates this Enduring Material for a maximum of 0.25 AMA PRA Category 1 Credit(s)™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Disclosure Statement

Joseph Bass, MD, PhD, has received honoraria from NovoNordisk but the relationship has ended. Course director, Robert Rosa, MD, has nothing to disclose. Planning committee member, Erin Spain, has nothing to disclose. Feinberg School of Medicine's CME Leadership and Staff have nothing to disclose: Clara J. Schroedl, MD, Medical Director of CME, Sheryl Corey, Manager of CME, Allison McCollum, Senior Program Coordinator, Katie Daley, Senior Program Coordinator, Michael John Rooney, Senior RSS Coordinator, and Rhea Alexis Banks, Administrative Assistant 2. All the relevant financial relationships for these individuals have been mitigated. 

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