Pennington Biomedical Panel: "Are We in Control of What We Eat?"

Several times a day, we decide what to eat—or at least we think we do. Our brain sifts through a vast array of information as we choose what and when to eat next. External factors such as price and availability interact with internal factors such as stress level and nutritional state, just to name a few. This raises a compelling question: Are we truly in control of what we eat?

Earlier this month, four esteemed Pennington Biomedical scientists gathered for a thought-provoking panel discussion to explore how we choose—and to what extent the decision is truly ours to make—how we will fuel our bodies.

Drs. Chris Morrison, Hans-Rudolf Berthoud and Heike Muenzberg-Gruening study this question from its most basic and foundational perspective. Vance Albaugh, MD, Ph.D., is a surgeon scientist, and analyzes this question from a clinical, human-focused lens.

"The brain has 100 billion neurons that interact with each other to create over 100 trillion connections. These connections hold your identity, personality, hopes, memories and emotions, and make the brain quite possibly the most complex structure in the universe," said Dr. Morrison, who led the lively discussion, likening it to "cramming a semester course into one evening."

Dr. Albaugh explained how MRIs highlight the fact that food or food cues activate unique parts of the brain. For example, when someone who has lost weight by reducing calorie intake is shown a donut, their brain will "light up like a Christmas tree," he said. In contrast, patients who lose weight through metabolic surgery do not show nearly that kind of brain activity in response to food images.

Dr. Morrison drew parallels from nature, referencing how hummingbirds balance their diet between nectar and insects. Remarkably, the hummingbird "knows" when to stop filling up on the sweet nectar and opt for protein. Dr. Morrison said mice react in the same way, motivated to eat protein rather than a tasty treat when their diet lacks enough protein.

The scientists acknowledged many dieters' frustrations: that people do not always lose weight when they try to eat less and move more. Dr. Berthoud said our bodies are made to gain weight, not to lose weight and that it is very difficult to change biology.

"Our subconscious drive to eat increases progressively for every pound we lose," he said.

Dr. Muenzberg-Gruening echoed this message.

"Our body defends itself against weight loss, and we know this response is mediated by distinct neural circuits within the brain" she said.

Dr. Albaugh reminded the guests that although weight loss surgery has the best and longest lasting results, scientists don't fully understand how it works. After surgery, patients often report things like, "I don't get hungry anymore," "I really crave cauliflower now," and "Certain foods like sweets just aren't that appetizing anymore."

Although some critics suggest that patients want to think this way after surgery (implying their reports aren't genuine), scientists have been able to duplicate this response in animal models. Studies have shown that prior to metabolic surgery, rats strongly prefer sweet and fatty foods, but after surgery their preference shifts to lower calorie foods—a biological shift that suggests deeper neural changes.

While neuroscience has revealed much about eating behavior, the panelists agreed that many mysteries remain. Solving these mysteries and increasing our understanding of the brain-body connection is essential to developing more effective obesity treatments. Discovering solutions for healthier, longer lives requires both federal research funding and private philanthropy.

The evening concluded with heartfelt thanks to Pennington Biomedical's longtime supporters, many of whom were in attendance, whose generosity has driven groundbreaking discoveries into how—and why—we eat.

Key Takeaways:

• While neuroscience has revealed much about eating behavior, many mysteries remain.
• Understanding the brain-body connection is essential for creating more effective treatments for obesity.
• Modern obesity treatments succeed by working with the brain's regulatory systems.
• Biology influences our relationship with food, but understanding these systems allows us to make better decisions about diet, exercise, and medical treatments. However, there is no universal solution that works for everyone.
• Advances in understanding brain function will drive the development of the next generation of obesity treatments.

About the Pennington Biomedical Research Center
The Pennington Biomedical Research Center is at the forefront of medical discovery as it relates to understanding the triggers of obesity, diabetes, cardiovascular disease, cancer and dementia. Pennington Biomedical has the vision to lead the world in promoting metabolic health and eliminating metabolic disease through scientific discoveries that create solutions from cells to society. The center conducts basic, clinical, and population research, and is a campus in the LSU System.

The research enterprise at Pennington Biomedical includes over 530 employees within a network of 44 clinics and research laboratories, and 13 highly specialized core service facilities. Its scientists and physician/scientists are supported by research trainees, lab technicians, nurses, dietitians, and other support personnel. Pennington Biomedical is a globally recognized state-of-the-art research institution in Baton Rouge, Louisiana. For more information, see www.pbrc.edu.

Provided by Louisiana State University