Why Do We get Fat? Part 1 – The Biggest Lie in Obesity Medicine

Picture of Dr. Jason Fung
Dr. Jason Fung

This is Why You’re Not Losing Weight (Its Not Calories)

Pre-order The Hunger Code – Out March 2026 at www.doctorjasonfung.com

Visit www.drinkaeira.com for hunger management tools.

Stop counting calories! It’s the biggest, most damaging lie in obesity medicine. In this video, Dr. Jason Fung, the best-selling author of The Obesity Code & The Hunger Code dismantles the single biggest myth in weight loss: Calories In, Calories Out (CICO).

For decades, we’ve been told that weight gain is a personal failing—a simple lack of willpower. Dr. Fung explains why this is completely false. He reveals that weight gain isn’t a calorie problem; it’s a hormonal problem. In this video you will learn:

  • Why the CICO equation, while technically true, is practically useless for weight loss.
  • The problem: Why your Basal Metabolic Rate (BMR) plummets when you cut calories, sabotaging your efforts.
  • The true Arrow of Causality: Hormones (not calories) are the real cause of weight gain.
  • How Insulin, the master hormone, forces your body to store fat and makes you hungrier.
  • Why 100 calories from a cookie is NOT the same as 100 calories from an egg.
  • The Circular Logic trap that keeps people fixated on counting.
  • How food acts as information that gives your body specific instructions.

This is a must-watch for anyone who has struggled with yo-yo dieting and is looking for the real, science-based solution to lasting weight loss.

�� If you’re serious about losing weight without losing your health or youthfu look, this video is a must-watch. ��

Subscribe now for more science-backed videos on fasting, weight loss, an metabolic health. And don’t forget to like ��, comment ��, and share this vid with anyone who still believes in the calorie deficit myth!

⏱️ Chapters / Timestamps

00:00 – The Biggest Lie in Obesity Medicine

00:40 – The Flawed Calories In vs. Calories Out Equation

01:15 – Why We Think Obesity is a Personal Failing (And Why It’s Wrong)

02:13 – Body Fat is Tightly Controlled by Hormones

03:02 – The Problem: Why Eating Less Fails

03:50 – The Inevitable Drop: Basal Metabolic Rate (BMR)

04:37 – The Real Cause of Weight Gain: Hormones

05:13 – The Master Hormone: How Insulin Makes You Fat

06:00 – Hormones Control Your Hunger & BMR (Not Willpower)

08:21 – The Circular Logic Trap of CICO

08:40 – Not All Calories Are Equal (Cookies vs. Eggs)

10:14 – Food is NOT Just Energy, It’s Information

11:09 – The Critical Choice: Store Calories or Burn Calories?

12:12 – Final Takeaway: Focus on Hormones, Not Calories

Responses

Health Coaching

Coaching Plans with our Health Coaches

  • Receive expert guidance on fasting, nutritional strategies and healthy habits
  • For individuals who are looking to lose weight, improve metabolic health and would like frequent contact with peer and coaching support
  • One complimentary Intake Assessment per client
  • Please review the coach’s bios and watch the videos to determine which coach is the best fit for your Intake Assessment
Book a free 15-minute Intake Assessment with one coach of your choice using the booking buttons below.

Group Coaching

$1,099 USD

13 TOTAL SESSIONS:

  • Twelve 60-minute group sessions, up to 4 participants
  • One 1-on-1 sessions
  • Six-month coaching program

BONUS:

  • Six months community access ($275 value)

Health Coaching

Coaching Plans with our Expert Health Coaches

  • Personalized fasting and nutritional plans catered to your health needs, goals and lifestyle
  • Coaching can help you make the changes that lead to a healthy, active lifestyle forever
  • This program is designed for those looking to burn body fat, improve metabolic health and tackle their mindset and behavior challenges
  • One complimentary Intake Assessment per client
  • Please review the coach’s bios and watch the videos to determine which coach is the best fit for your Intake Assessment
Book a free 15-minute Intake Assessment with one coach of your choice using the buttons below. 
An Intake Assessment is to your chance to meet the coach and learn how they can help you. Coaching is an investment and we want you to find the right coach for you. This is not a sales call. The coach will send you the links to purchase via email after the session. 
Please review all of the package options below before booking your Intake Assessment.

Packages start at $1,799 USD. Keep scrolling for more information.

Total Transformation

1-on-1 Coaching

$2699 USD

8 TOTAL SESSIONS:

  • Eight 45-minute 1-on-1 sessions ($3192 value)
  • Six months community access ($275 value)
  • Six-month coaching program

Total Transformation

Group Coaching

$1799 USD

14 TOTAL SESSIONS:

  • Twelve 60-minute group sessions, up to 4 participants
  • Two 1-on-1 sessions
  • Six months community access ($275 value)
  • Six-month coaching program

Single Session

$399 USD

1 SESSION:

  • One 45-minute 1-on-1 session

The Diabetes Code Cookbook

Delicious, healthy, low-carb recipes to manage your insulin and prevent and reverse Type 2 Diabetes

By Jason Fung, MD

Life in the Fasting Lane

Making intermittent fasting a lifestyle

By Jason Fung, MD, Eve Mayer, Megan Ramos

The PCOS Plan

Prevent and reverse polycystic ovary syndrome through diet and fasting

By Nadia Brito Pateguana, ND, Jason Fung, MD

The Cancer Code

A revolutionary new understanding of a medical mystery

By Jason Fung, MD

The Longevity Solution

Rediscovering centuries-old secrets to a healthy, long life

By James DiNicolantonio, PhD, Jason Fung, MD

The Complete Guide to Fasting

Heal your body through intermittent, alternate-day, & extended fasting

By Jason Fung, MD and Jimmy Moore

The Obesity Code

Unlocking the secrets of weight loss

By Jason Fung, MD

The Essential Guide to Intermittent Fasting for Women

Balance your hormones to lose weight, lower stress, and optimize health

By Megan Ramos

The Diabetes Code Journal

The official workbook for reversing Type 2 diabetes through healthy eating and fasting

By Jason Fung, MD