Science Friday It’s Not Just You—Bad Food Habits Are Hard To Shake
Oct 14, 2025
Dr. Kevin Hall, a nutrition scientist and former NIH researcher, explores the complex relationship between weight loss and metabolism, drawing from his experience studying contestants on The Biggest Loser. He reveals surprising findings about metabolic slowdown despite intensive exercise and the challenges of maintaining weight long-term. Julia Belluz, a science journalist and co-author of Food Intelligence, discusses how modern ultra-processed foods disrupt our innate appetite signals. Together, they tackle nutrition myths and suggest ways to improve our food environment.
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Internal Signals Guide Eating
- People possess a complex internal system that guides eating beyond conscious willpower.
- Modern food environments interrupt those signals and drive unhealthy eating patterns.
Research On The Biggest Loser
- Kevin Hall joined The Biggest Loser as a researcher to observe a natural experiment on extreme diet and exercise.
- He studied whether intense exercise prevented the typical metabolic slowdown seen after weight loss.
Exercise Didn’t Prevent Metabolic Slowdown
- Despite three hours of vigorous daily exercise, contestants' metabolic rates slowed by hundreds of calories.
- Those with the greatest metabolic slowdown had lost the most weight initially.
