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Centuries of Evidence: Why Diets Don’t Work

Fat Science

Release Date: 09/15/2025

Why GLP-1 Medications Work Even When the Scale Doesn't Move show art Why GLP-1 Medications Work Even When the Scale Doesn't Move

Fat Science

What if the scale isn't moving, but your health is dramatically improving?

If you've ever felt discouraged because the number on the scale won't budge—even on a GLP-1 medication—this episode will change how you think about these drugs. Dr. Cooper breaks down the research showing that the biggest benefits have nothing to do with weight loss. It's all about metabolic health.

This Week on Fat Science

Dr. Emily Cooper, Mark Wright, and Andrea Taylor expl

info_outline Mailbag: Food Tracking, Mechanical Eating Troubleshooting, COVID & Metabolism, and Metformin + GLP-1 Synergy show art Mailbag: Food Tracking, Mechanical Eating Troubleshooting, COVID & Metabolism, and Metformin + GLP-1 Synergy

Fat Science

This week on Fat Science, Dr. Emily Cooper, Mark Wright, and Andrea Taylor answer listener mailbag questions from California, the UK, France, Washington, Wyoming, and beyond. 

The team breaks down why Dr. Cooper does not recommend calorie tracking (and when limited tracking can make sense), how to build confidence in eating without data, and why “mechanical eating” sometimes needs medical customization—especially for people with slow gut transit or gastroparesis-like symptoms.  info_outline Mailbag: GLP-1 Weight Regain, Meals vs Snacks, and Why Some People Don’t Respond show art Mailbag: GLP-1 Weight Regain, Meals vs Snacks, and Why Some People Don’t Respond

Fat Science

his week on Fat Science, Dr. Emily Cooper, Mark Wright, and Andrea Taylor answer listener mailbag questions that get to the heart of metabolic health. The team explains the real difference between meals and snacks, discusses whether GLP-1 medications can be appropriate for children in complex cases, explores why some people appear to be “non-responders” to Wegovy, and breaks down why alarming headlines about rapid weight regain miss the bigger metabolic picture. They also explain how to set

info_outline What the Headlines Get Wrong About GLP-1 Drugs and Metabolism show art What the Headlines Get Wrong About GLP-1 Drugs and Metabolism

Fat Science

This week on Fat Science, Dr. Emily Cooper, Mark Wright, and Andrea Taylor break down two GLP-1 studies that challenge a major media myth: GLP-1 medications don’t drive weight loss just because people eat less. Instead, drugs like tirzepatide and semaglutide create direct metabolic shifts—including increased fat oxidation and improved fuel partitioning—regardless of appetite.

The team also explores mechanical eating, the psychological impact of “diet food,” and Andrea’s 13-yea

info_outline GLP-1 Mailbag: Weight Regain, Leptin Resistance, Hypoglycemia & Why Calories Aren’t the Problem show art GLP-1 Mailbag: Weight Regain, Leptin Resistance, Hypoglycemia & Why Calories Aren’t the Problem

Fat Science

This week on Fat Science, Dr. Emily Cooper, Mark Wright, and Andrea Taylor tackle a wide-ranging mailbag episode with listener questions from the U.S., UK, and Europe. Topics include unexpected weight regain on GLP-1s, post-meal sleepiness and hypoglycemia, metabolic dysfunction despite normal labs, GLP-1 dosing strategies, and why these medications are about metabolism, not appetite suppression.

Key Questions Answered

More Episodes

This week on Fat Science, Mark Wright, Andrea Taylor, and Dr. Emily Cooper dig deep into the science and history behind why diets don’t work for lasting weight management. From early fad diets, through to modern metabolic research, the episode explains why calorie restriction often backfires—and why fueling the body is key to long-term health.

Dr. Cooper unpacks the latest evidence about metabolic adaptation, the hormonal drivers of weight regain, and the persistent harms caused by repeated dieting. Listeners will leave with a renewed understanding of metabolism’s complexity, the importance of medical advocacy, and the critical need to challenge diet culture and weight bias.

Key Takeaways

  • Short-term weight loss from dieting is common, but centuries of evidence show most weight is regained—sometimes with additional harm.
  • Metabolic adaptation and hormonal changes (like drops in leptin and rises in ghrelin) make weight regain almost inevitable for most people after calorie restriction.
  • Repeated dieting (weight cycling) increases the risk of cardiovascular disease and visceral fat, not just regaining lost weight.
  • The biggest breakthroughs in metabolism came in the 20th century, but weight bias and diet industry profits keep the focus on ineffective short-term strategies.
  • True long-term progress rests on regular fueling, metabolic evaluation, and avoiding the trap of repeated restrictive diets.

Expert Insights & Practical Advice

  • Dr. Cooper highlights landmark studies (Minnesota Starvation Experiment, Dutch famine, the "Biggest Loser" follow-up) illustrating how diets slow metabolism and can even cause lasting damage.
  • The science behind metabolic hormones—leptin, ghrelin, adiponectin, GLP-1—shows why the body fights back against weight loss and why medications must be paired with metabolic support, not additional restriction.
  • Reflections on weight bias in medicine, the need for informed consent around diets, and how current research is still catching up to clinical reality.

Personal Stories & Culture Critique

  • Andrea shares how social circles demonstrate the futility of diets and the cycle of weight loss and regain.
  • Mark recounts professional experiences highlighting systemic bias and cultural attitudes toward weight and health, advocating for preventive medicine as the path forward.
  • The hosts challenge listeners to rethink their relationship with food, prioritize health, and push back against societal shame and stigma.

Resources from the Episode

Fat Science is committed to debunking the myths about metabolism, diabetes, and fat. We empower listeners with evidence-based information, challenging the culture of blame and restriction. This podcast is for informational purposes and not medical advice.

Fat Science: No diet, no agenda—just science that makes you feel better.