This episode features Dr Jason Fung, a Nephrologist (Kidney Doctor) who has spent over 25 years researching the best way to lose weight and prevent disease. Head to to get your free sample pack with any purchase.
In this episode, Dr Fung discusses the causes of obesity and how hormones play a vital role in fat storage and weight gain. Dr Fung discusses the difference between the hormonal theory and the calories theory, pertaining to the best way to lose adipose fat and regain metabolic health.
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Dr Fung discusses the key hormone of insulin, how elevated levels of insulin in the body lead to chronic inflammation, and the physiology of how this happens. Dr Fung explains how certain foods we eat elevate insulin and cause us to store fat in the fat cells. And while what we eat matters, when we eat is also important to release adipose tissue (body fat).
Dr Fung discusses the role of intermittent fasting, extended fasting, and autophagy to reduce inflammation and why the consumption of too much protein can inhibit autophagy and mitophagy. Dr. Fung also discusses the role of common weight loss medications like Ozempic and their effect on weight loss and insulin resistance.
This episode is important for anyone who is overweight, those who have tried every diet or count calories and failed, and who seek to know the science behind how to lose weight and keep it off. You will learn the science of lipolysis (how the body burns fat) and effective dietary and lifestyle protocols to improve metabolic health and fix obesity.
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Timestamps:
00:00 Intro
03:11 The main cause of obesity
13:40 Dr Jason Fung + The Obesity Code
21:10 Hormones vs calories for weight loss
30:59 Calorie deficits for weight loss
37:27 Tool: How to lower insulin with fasting
39:44 The natural fasting window
43:28 Dr Fung’s opinion about breakfast
46:55 Intermittent Fast Study (91% increase in CV events)
51:20 Tool: Best fasting windows
53:56 Protein effects on autophagy
58:24 Processed foods: Effects insulin and weight loss
01:02:38 Carbohydrates: Effects on weight loss and insulin
01:05:22 Fasting vs Ozempic for weight loss
01:10:11 The versatility of fasting vs a diet
01:11:56 Tool: Focus on hormones not calories for weight loss
#drjasonfung #intermittentfasting #weightloss
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Watch Next: Fasting Fixes Heart Disease: https://youtu.be/BCOSeZIQFrI
If you enjoyed this, please double check you have ‘liked’ and ‘subscribed’ to the channel – thanks for your interest in health – Rina
Dr. Fung saved my life. And since I've been watching you, my understanding has grown. I "don't" have diabetes any more. I've lost 50lbs so far. And I'm off two heart meds and diabetic meds. as my blood pressure is now normal or below. THANK YOU FOR ALL THAT YOU DO THROUGH PRIMAL PODCAST. You are an awesome human bean 🙂
I don’t like the interviewer. Calories haven’t been in the equation since 1990
Question: If it is not about calorie intake-even healthy foods-then why when someone has bypass or sleeve surgery and have to cut their calories in a drastic way-do they lose weight? Thank you for replying.
Can someone simplify what he's recommending as the fastest way to lose weight
There is no "#1 doctor."
Thank you so much!
Greetings from Greece 🇬🇷
So I fast 12 hours every day. I am not losing weight. Help
Got my body into ketosis with low carb foods. Then went to one meal a day. Then to fasting mimicking diet. So far 7 days and swelling in knees, legs and feet has disappeared. Doing great feeling good and I’m over 70
I completed a 40-day water fast—no food whatsoever. Forty days fully locked in, driven by discipline, faith, and my interest in autophagy. The full journey is on my YouTube channel if you’d like to see what it truly took.
Bro is not the creator of intermittent fasting or the first to talk about it.
True…but one of the reasons fasting works is because its putting you in a calorie deficit.
Refeeding syndrome is extraordinarily dangerous
I can’t sleep while fasting, what should i do now?
As a calorie counter, I do not think like that- there is proof that higher-calorie foods are those foods that spike insulin. I always reach for a larger bowl of veggies and a lean protein on the side to fill myself instead of a low-calorie burger or cookies. If I want a dessert, I go for substitutes that don't involve any of those ingredients that spike it.
this guy is a freaking genius, this is the REAL way to target belly fat because visceral fat is the first to go while you're in a fat-burning fasted state
How about drinking apple cider vinegar with water in the morning? And also eating fruits like raw natural fruits? Won’t that spike glucose levels ? Thanks , great interview!!
Took my GP’s instruction: skip breakfast, lunch at 2pm dinner before 7pm. Meat, fat and cabbage. No sugar, no grains. Anything sweet I avoid. Starch I avoid.
I started at 94.5kg on 26/5/26. Today 23/7/26 I’m 82.7kg.
I’m going to get to 75kg. Berlin or bust!
20:30 wtf salt ad 😂😂🙄🙄 this presenter could be replaced by AI easily
I’ve never thought about the body in this way but it makes so much sense thank you for this information it’s truly eye opening
1:04:10 my carbs a day range from 1 to 5 grams of carbs usually I stay at 1 g of carbs a day
59:27 after fasting I eat eggs,bacon butter and meat ONLY
I need ozempic, I enjoy food too much
I also want reduce some pounds
What about Post Menopause women?
he literally never mentions "14 days" in the entire video…
New to Dr. Fung. Wish he was my doctor.
I’m not fat I’m 68 yrs old. I have high blood pressure diabetes and really bad joint arthritis. I font want to lose more weight. But how can I help myself heal naturally? I’m so stressed and in pain
Fasting saved my life! No more high cholesterol, inflammation completely decreased. Mediterranean diet now, no dairy, no gluten. Lost dramatically in 8 weeks…. Inflammation is horrible for your health.
Informative but the message gets lost because this fellow is way too long winded
Sick and Fat? GMO's Pesticide filled food. Plastic meat. More More- The food is killing us and the water is F'd up too.
26old, started to do 36h but now im on 48h and keep going bcouse i feel good, no hunger, also im exercising. 99-96.7kg just on this 2 days
I’ve been IF most my life unintentionally… I stop eating at 6pm and then break my fast around 11am. Sometimes even 2pm. Yet here I am overweight due to high cortisol due to a personal matter. 😢 stress will abolish all your good work.
Dr.Fung is amazing 👏 I love all of his books
How do you control and prevent hypoglycemia and falling asleep when you are constantly too cold & fatigued to eat.
I WORKED AT JDRF FOR 23 YEARS BEFORE I RETIRED FROM THERE. I NEVER HEARD ONE DOCTOR MENTION INTERMITTENT FASTING. ONLY SHOOTING INSULIN TO HELP WITH YOUR TYPE 2 DIABETES AND PILL FOR TYPE 1 DIABETES AND DONT EAT SUGAR. DOCTORS ARE KILLING PEOPLE WITH THE WRONG INFORMATION. I REALY LIKE DR. JASON FUNG! HE HELPED ME LOSE WIEGHT WITH FASTING. I'M FASTING NOW TO LOSE 80LBS,
I think the coolest thing is that I haven’t been military-like with how strict I’ve been, but I’m down exactly 50lbs as of Thanksgiving 2025 (7 months). This shows that you don’t need to be perfect for this to work. Just start slowly and find what works best for you.
I am OMAD for 5 days and two days no food. Works like a charm and I feel amazing!
Doesn’t Ozempic cause health issues?