Why Do We get Fat? Part 1 – The Biggest Lie in Obesity Medicine
This is Why You're Not Losing Weight (Its Not Calories) | Dr. Jason Fung
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!
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⏱️ 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
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�� BOOKS:
�� The Obesity Code – Reviewing underlying physiology of weight loss an
how low carb diets and fasting can help.
?…
�� The Diabetes Code – Reviewing how type 2 diabetes is a reversibl
disease and dietary strategies. ?…
�� The Cancer Code – Scientific exploration of how cancer develops
?…
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�� YouTube Medical Lectures (for specialist physicians)
▶️ The Roots of the Obesity Epidemic: https: // • The Obesity Epidemic,
Explained
▶️ Therapeutic Fasting – The Two Compartment Problem:https: // •
Fasting and Weight Loss – Solving the…
▶️ Does Calorie Counting work?: • Why Calorie Counting rarely leads to
…
▶️ Two Big Lies of Type 2 Diabetes: • Two Big Lies about Type 2
Diabetes
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#WeightLoss #ObesityCode #InsulinResistance #CICO #Hormones
#JasonFung #WeightGain #DietMyths #Metabolism
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Pre-order The Hunger Code at http://www.doctorjasonfung.com. Check out hunger management tools at http://www.drinkaeira.com!
Done! Just ordered two! One to share😁. Thank you for all you do!
I’m celebrating six years this month since stumbling upon your videos and books. I lost 160lbs and I’m maintaining well on ketovore and a fasting lifestyle. Thanks again! 👍😃
Bravo doc, you changed my life! I was obese and drugged up in a hospital when I started watching your God-sent videos. I took my chances, giving up all the diabetes treatments and took,the path of diet, fasting, meditation and exercise. Five years hence, I feel ever so grateful to you for the weight loss, great health and wellness. So thank you, the true hero to so many around the world!
Def make the rounds in the bodybuilding, hormone optimization channels. The professional bodybuilding community is 20 years ahead in Hormones and Mens health. But it tries to over simplify HPTA, Traumatic Brain Injury, Insulin Resistance, and Environmental/Drug/Alcohol Induced, and bad food quality. Then the drug companies pushing drugs to slow down digestion with Hashimotos and other gut illness.. The whole system needs an overhaul…
@JohnsonNestorFamilyYou’re amazing well done 👍
Love this guy
Am I the only one who gets super excited whenever I see a new notification from this channel? 😄🔥
Me tooo
Me too😊
I do!
Oh yeah
I think it’s just you guys, this info has been out there for about a decade from this same guy. He has a website that goes in depth into all this stuff
I took Dr. Fung’s advice last winter. Using intermittent fasting I cured my insulin resistance. This then allowed my body to burn fat as fuel. So running and eating inside a time window (noon to 5) led me to lose 30 pounds. I’ve never felt better. My new problem is now I am addicted to running.
Use black ginger powder omg brilliant. White sugar causes insulin resistance as well as being routine with food.
@geo_neo9 To be more accurate, excessive carbohydrates consumed too frequently causes insulin resistance. You are being way too simplistic saying white sugar is the cause.
@patrickh709 I am sure that white sugar is the worst possible option. Overall I don’t think there is anything wrong with avoiding refined sugars.
Wow that is great, I am happy for you. I wish I could say the same, I tend to ramble so I’ll try to be brief. 11 to 13 weeks ago I got blood work and everything was bad. A1c was 11.8 triglycerides high liver enzymes high force my hand and I pretty much want keto/carnivore and started to intermittent fast and actually did a three day fast in that time, I honestly did not lose more than 1 to 3 pounds two things that I could advance that I did not do was put myself in a heavy caloric deficit because to me that it’s just a recipe for disaster and I did not walk 2000+ steps a day. I am not 35 years old and I had never in my life whenever I did get disciplined as I am have problems with losing weight. I made a sheer loss your words and the stress of this has caused me to turn back to cheat fast food these last two weeks, but trying to return it around 80 advice or tips would be a blessing
This happened to me about 5 years ago. Running. The best thing ever. Lol. 🎉
This guy is saving my life!
Bravo doc, you are the hero who got me off the terrible diabetes drugs and got me on the heavenly diet and fasting path weight loss, great health and wellness.
“Calories don’t cause obesity.” We don’t ‘eat’ calories as well. I don’t bother counting calories, so I eat as much healthy whole foods that I like until I’m full. No worries about weight or fat gain for me
I’m going to watch this a hundred times and share it with everyone! 😀
Thank you for not giving up on explaining this! Each time it makes a little more sense. ❤
I’m doctor and this reminded me of “The Great Health Deception” by Frank Dalton. If real health matters to you, this book is must read.
Exactly! It goes beyond conventional medicine.
Scammer bot account!
Scammer/spammer!
@ThomasHughes-u8v Same person/bot but under a different name!
Rubbish. Bot! Bot! Bot!
Amazing explanation as always, Dr. Fung! Thank you so much for everything you do. You’re truly a lifesaver for those of us trying to get our health and weight under control. We appreciate you more than words can say! 💖
Brilliant new articulation, I might use for my family: Food equals not just the calories, but contains information about what to do with those calories. Spinach and Cookies carry different instructions, since one stimulates the ‘hunger and fat storage hormone’ and the other food does not–even when those calories are equal and the same!
Complete brilliance, makes so much sense
My doctor told me about The Science of Lasting Health by Dr. Samuel Royce, and I’m so glad I gave it a chance. It really opened my eyes — it’s never too late to start changing your habits and feeling better.
Spammer/scammer account!
@barefoot-earth Not a spammer but pure scammer. And then they use bots to have the likes so the scammer’s post would be on top.
I’m a doctor, and Healing Beyond The System by David Collins breaks this down better than anything I’ve read. Really wish I’d read it earlier.
this book is amazing trust me
Im a doctor as well…
@kostar500 Damn! I was nearly thinking you’re a scammer, too. But then I have realised you’re being sarcastic.
What the modern health care system also refuses to evaluate is Androgen’s, Growth Hormone, Thyroid, and optimizing these to be healthy in the first place..
My name is Sunil & I am from Bangalore, having T2 Diabetes for 25 yr, HBA1C 7 with tablet… After listening to Dr Jason as well as few others on you tube , since last 4 motnhs , i Minimized my Carbs intake ( mainly Roti/Rice/bread), stopped all Processed food, started only 2 meals at 11:30 am & 7 pm, no in between snacking, My latest HBA1C is 6.1 !! Weight reduced from 70 kg to 66 kg, feeling very energetic. Thank you for wonderful insights & making us believe we can beat Diabetes, God Bless you Sunil
Congrats!!! And ty for sharing your real life experience!
@jenniferkannapel9450 Thank you…pl let me know what do you mean by Real life Experience? I will be happy to Elaborate….points mentioned by me are my present real life routine
@sunilw123yes. That is what I meant. I appreciate that you shared your real life experience. Continually naysayers point to ‘no scientific studies’. I think that your experience is a scientific study and should be appreciated:-)
Give a type 1 diabetic 5,000 calories a day, they’ll still waste away. Inject them with insulin and they’re going to fatten right up. So much for calories in/calories out.
“” in 5 years, I should weigh – 100 pounds “” 😂😂👏
Dr Fung’s books and videos inspired me to do time restricted eating. I started at 95 kg in July 2025, I’m today at 79 kg (November 13, 2025), and on track to achieve my target healthy weight of 70 kg. 🎉🎉🎉