TED Health Why your body fights weight loss | Katherine Saunders
Aug 19, 2025
Katherine Saunders, a physician specializing in obesity, dives deep into the biology behind our struggle with weight loss. She explains that obesity is not just about willpower but is rooted in our evolutionary biology. The discussion touches on how our bodies are wired to store fat and the hormonal changes that can sabotage dieting efforts. With insights into the latest treatments and the complex nature of obesity, Katherine advocates for empathy and a shift in societal perceptions surrounding this chronic disease.
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Evolution Primes Us To Store Fat
- Human bodies evolved strong anti-starvation responses that favor storing calories to survive scarcity.
- That same biology now promotes weight gain in environments with abundant food.
Diet Can Damage The Brain’s Weight Thermostat
- A high-fat diet can inflame hypothalamic neurons and break the brain's hunger-and-satiety signals.
- This impaired signaling makes fullness harder to detect and promotes further fat storage.
Weight Gain Creates A Self-Reinforcing Cycle
- Weight gain creates biological changes that further drive eating and slow metabolism, producing a vicious cycle.
- When people diet, hormones like ghrelin rise and metabolic rate falls, making sustained weight loss difficult.