This Isn’t a Willpower Problem: The Truth About Stress, Cravings & Weight Gain

About this episode

In this episode, Dr. Brendan McCarthy—Chief Medical Officer at Protea Medical Center—dives into one of the most misunderstood topics in health: Why does it feel like you can’t stick to a diet… even when you’re trying your best? This isn’t about willpower. It’s not a character flaw. And it’s not your fault. Dr. McCarthy breaks down the biology behind stress, cravings, and weight gain—explaining how chronic stress rewires your brain, alters decision-making, and drives you toward hyper-palatable, ultra-processed foods. YouTube citations : 1. Arnsten, Amy F. T. “Stress Weakens Prefrontal Networks: Molecular Insults to Higher Cognition.” Nature Neuroscience, vol. 18, no. 10, 2015, pp. 1376–1385. Why it is here: Foundational paper for the claim that uncontrollable stress increases catecholamine signaling in the prefrontal cortex and degrades higher-order control, working memory, and inhibition. This is one of the strongest anchors for the idea that stress makes the pause smaller. 2. Schwabe, Lars, et al. “Concurrent Glucocorticoid and Noradrenergic Activity Shifts Instrumental Behavior from Goal-Directed to Habitual Control.” Journal of Neuroscience, vol. 30, no. 24, 2010, pp. 8190–8196. Why it is here: One of the most important papers for your “click-boom” model. It shows that stress chemistry can bias behavior away from goal-directed control and toward habit-like responding. That is not a morality argument. It is control architecture. 3. Plessow, Franziska, et al. “The Stressed Prefrontal Cortex and Goal-Directed Behaviour: Acute Psychosocial Stress Impairs the Flexible Implementation of Task Goals.” Experimental Brain Research, vol. 216, no. 3, 2012, pp. 397–408. Why it is here: Strong support for the claim that acute psychosocial stress impairs flexible goal implementation. Useful when you want to say that under stress, the person may still know what matters but have reduced access to that guidance in the moment. 4. Maier, Silvia U., et al. “Acute Stress Impairs Self-