The Obesity Code aims to clear up myths on weight loss, and provide a simple formula for long term success. Below I’ll discuss aspects from the book, including an example diet plan at the bottom.

Since writing The Obesity Code Jason has followed up with The Diabetes Code (aimed at helping people prevent or reverse type 2 diabetes), and The Complete Guide to Fasting (which covers intermittent and extended fast details).

Jason Fung – Author of The Obesity Code

Hormonal Roots of Obesity

Jason suggests that to understand weight loss requires understanding the hormonal roots of obesity. He explains that the hormone insulin is the key driver of obesity. Therefore obesity is a hormonal, not a caloric imbalance. He recommends we focus on two key areas:

  • What to eat
  • When to eat

What to Eat & What Not to Eat

What to Eat?

The book doesn’t tell you specifically each and every food you should eat. Instead Jason outlines some general principles for eating:

  • Reduce intake of refined grains and sugars
  • Moderate protein consumption
  • Increase natural fats
  • Maximize protective factors such as fiber and vinegar
  • Choose only natural, unprocessed foods.

What Not to Eat?

Jason mentions a few specific examples of what not to eat:

  • Sugar – Don’t add it to anything you eat or drink. Check food & drink labels to ensure sugar hasn’t been added to anything you buy. See below for other common names of sugar*.
  • Snacks – Jason recommends you cut out all snacks between meals. Constant stimulation of insulin leads to insulin insensitivity.
  • Sauces – Barbecue, plum, honey garlic, hoisin, sweet & sour and other dipping sauces contain large amounts of sugar. As do commercial salad dressings and ketchup.
  • Candy – It probably goes without saying that chocolate and sweets should be avoided completely (except for dark chocolate that’s 70% cacao content or greater).
  • Desserts – these are generally high in sugar and should be avoided. Replace with seasonal fruits (optionally with whipped cream) or dark chocolate. Save less healthy desserts for special occasions, but don’t make them a regular occurrence.

*Other common names for sugar are sucrose, glucose, fructose, maltose, dextrose, molasses, hydrolyzed starch, honey, inverted sugar, cane sugar, glucose-fructose, high fructose corn syrup, brown sugar, corn sweetener, rice/corn/cane/maple/malt/golden/palm syrup and agave nectar. Don’t let manufacturers trick you into consuming excess sugar under the guise of a different name.

Then in regard to the highly glycemic, popular staples; bread, pasta, potatoes and cereals

Bread & Pasta – Jason suggests the consumption of bread and pasta should be minimized for a number of reasons:

  • Low nutritional value (processing removes most fibre and vitamins)
  • High glycemic effect (big increase in blood glucose level, which then requires a spike in insulin to regulate it)
  • Easy to over consume & may be addictive

Rice – Jason notes that many Asian populations have eaten diets based on highly refined white, polished, rice. Yet, until recently, obesity and diabetes remained rare in these populations. It has only been since they added sugars and processed foods to their diet, that obesity and diabetes have become rampant. This shows us that it’s possible to consume white rice and stay healthy. However, for those looking to lose weight, white rice is highly glycemic, and should be minimized.

Potatoes – Jason notes that potatoes are highly glycemic and consumption should be minimized. He does however point out that potatoes served cold and dressed with vinegar as a salad had 43% lower glycemic index1 – in part due to the cold increasing the resistant starch content of the potatoes.

Cereals – Jason has two main messages for breakfast. The first is that it shouldn’t be considered “the most important meal of the day”. If you’re hungry in the morning, and want to eat; do. But if you’re not, and instead want to break your fast at midday with grilled salmon and a side salad, then that’s perfectly acceptable. Jason’s second message is that many breakfast foods such as cereals, breads, muffins, Danish pastries etc. are highly problematic, and should be avoided. If you must eat cereals, he says, eat those containing less than 0.8 of a teaspoon (4 grams) of sugar per serving.

Foods Jason Specifically Recommends:

  • Eggs – Inaccurately demonized due to cholesterol concerns, eggs are in fact incredibly healthy. They can be enjoyed in many ways, including scrambled, over easy, sunny side up, hard-boiled, soft-boiled, poached, etc.
  • Seasonal fruits in moderation
  • Traditional yogurt and Greek yogurt. Make sure they are sugar-free.
  • Oatmeal – whole and steel-cut are good. Avoid instant oats which often add sugar.
  • Nuts – Macadamia, cashews, walnuts and pistachios are all high in healthy monounsaturated fats and low in carbohydrates. Watch out for peanuts, which aren’t technically a nut (they are legumes) and should be consumed in moderation.
  • Coffee & Tea. Avoid adding sugar or sweeteners. Cinnamon or other natural spices can be used to enhance the flavor.
  • Wine – moderate consumption of red wine (up to 2 glasses per day) typically does not impair insulin sensitivity, and therefore may be enjoyed.
  • Bone broth. See below for more details on bone broths.

(Note: this list of foods Jason recommends in Obesity Code is not exhaustive, for example it doesn’t mention things like meat and fish, which Jason is a proponent of. You can reasonably assume that if food is natural, unprocessed and consumed in moderation; it’s ok for Jason’s diet protocol).

 

The hormonal obesity cycle – showing the effects of excess glucose and fructose (image via IDM program)

When to Eat

  • Balance insulin-dominant periods with insulin-deficient periods (balancing feeding & fasting). Eating continuously is a recipe for weight gain
  • Intermittent fasting is a very effective way to deal with when to eat

Sleep

Beyond what to eat & when to eat, Jason touches on another factor that affects insulin levels; sleep. Not only does sleep affect insulin sensitivity, it also affects our ability to self-control, and our desire for carbohydrates (increased grehlin levels, which is a hormone responsible for hunger signalling). Thus people who are chronically sleep deprived will often (through no fault of their own), make more impulsive food decisions, and crave more carbohydrates. Therefore its important that if sleep deprivation is a factor, it gets tackled alongside the dietary choices.

This image shows the difference in insulin secretion between a diet with no snacking, and a diet where food is constantly consumed. Insulin = energy storage. Therefore you want to have decent breaks in insulin secretion for a healthy body.

Sample 7-Day Meal Plan – 24-hour Fasting Protocol

The below meal plan effectively means that every other day you are partially fasting from dinner through to dinner (24 hours). To make this slightly more do-able, Jason suggests incorporating a cup of vegetable, chicken or beef broth in place of where lunch would be.

Treat the exact contents of the meals as guidelines only, to be tweaked to your own taste. If you need to increase the quantities of food to reach satiety, do so. As long as when you’re fasting, you stick to it.

You may notice that only 3 of the 7 days include a dessert for dinner – this seems to be Jason’s way of explaining that sweet foods should be an occasional treat, rather than consumed daily.

Monday Tuesday Wednesday Thursday Friday Saturday Sunday
Breakfast FAST DAY
Water
Coffee
Western omelet
Green apple
FAST DAY
Water
Coffee
All-Bran Buds with milk
Mixed berries
FAST DAY
Water
Coffee
Two eggs
Breakfast sausage/bacon
Strawberries
FAST DAY
Water
Coffee
Lunch FAST DAY
Water
Green tea
1 cup of vegetable broth
Arugula salad with walnuts, slices of pear, goat cheese FAST DAY
Water
Green tea
1 cup of chicken broth
Ginger chicken lettuce cups
Stir-fried vegetables
FAST DAY
Water
Green tea
1 cup of beef broth
Baby spinach and lentil salad FAST DAY
Water
Green tea
1 cup of vegetable broth
Dinner Herbed chicken
Green beans
Mixed berries for dessert
Asian grilled pork belly
Baby bok choy stir-fry
No dessert
Halibut pan-fried in butter and coconut oil
No dessert
Indian chicken curry
Cauliflower
Green salad
No dessert
Baked catfish
Sautéed broccoli with garlic and olive oil
Seasonal fruits for dessert
Peppered steak
Asparagus
Grilled chicken salad
Dark chocolate for dessert

Note: On mobile devices, you may need to scroll right to read the full table.

In case it’s of use, I’ve made a PDF version of the above table so you can print it out. Additionally I’ve made a second version with empty spaces for the meals, that way you can program your own meal details:

Sample 7-Day Meal Plan – 36-hour Fasting Protocol

This version differs from the above, in that rather than fasting from dinner through to dinner every other day, you fast from dinner through a whole day, until breakfast 2 days later (again, repeating the fast every other day).

Monday Tuesday Wednesday Thursday Friday Saturday Sunday
Breakfast FAST DAY
Water
Coffee
Western omelet
Green apple
FAST DAY
Water
Coffee
All-Bran Buds with milk
Mixed berries
FAST DAY
Water
Coffee
Two eggs
Breakfast sausage/bacon
Strawberries
FAST DAY
Water
Coffee
Lunch FAST DAY
Water
Green tea
1 cup of vegetable broth
Arugula salad with walnuts, slices of pear, goat cheese FAST DAY
Water
Green tea
1 cup of chicken broth
Ginger chicken lettuce cups
Stir-fried vegetables
FAST DAY
Water
1 cup of beef broth
Baby spinach and lentil salad FAST DAY
Water
1 cup of vegetable broth
Dinner FAST DAY
Water
Green Tea
No dessert
Asian grilled pork belly
Baby bok choy stir-fry
No dessert
FAST DAY
Water
Green Tea
No dessert
Indian chicken curry
Cauliflower
Green salad
No dessert
FAST DAY
Water
Green tea
Seasonal fruits
Peppered steak
Asparagus
No dessert
FAST DAY
Water
Green tea
No dessert

Note: On mobile devices, you may need to scroll right to read the full table.

Bone Broth

A core aspect of Jason’s diet regimen is the consumption of bone broth on days when fasting. There are a few key benefits to this:

  • Its low in calories and almost zero carbohydrates, thus not impacting significantly on the health benefits of abstaining from food
  • Its high in amino acids such as proline, arginine and glycine, as well as minerals such as calcium, magnesium and phosphorus
  • The salt and minerals help with staying adequately hydrated during the fast

Vegetarians – The substitute to a bone broth would be a vegetable broth. So you’d essentially just cook a vegetable soup (without blending), then strain the vegetables and leave the low carb, tasty wholesome broth.

Simple Bone Broth Recipe

At its core bone broth is very easy to make, it’s essentially the simmering of bones for 12+ hours. If any complexity creeps in, its in the sourcing of good bones, and then the additional ingredients that add to the flavour. These are the key things you need to begin:

  • Having a slow cooker (aka crock-pot) is ideal – but if you’re cooking on the stove, you just need to make sure you have a large pot
  • Sieve or strainer at the end to separate bones from the broth
  • Chicken or beef bones
  • 1 tablespoon of vinegar to help extract the bones nutrients (Apple cider vinegar is a healthy choice)
  • Sea salt (or pink Himalayan salt) to taste
  • (optional) Additional seasoning and vegetables, to taste

If you’re cooking a chicken broth, perhaps the simplest way to acquire the bones is to purchase an (ideally organic) chicken. Cook it and first use it for the meat, then when finished, use it for your broth.

When you’re packing the chicken into your pot, its beneficial to crack some of the bones to let out more flavour and nutrients. This can be done by pushing down on the carcass until you hear cracks, alternatively some people go as far as to individually crack the bones with some scissors.

For a beef broth, it’s generally easy enough to source bones from a local butcher or market. Ideally grass fed cow bones, although this pushes the price up. That said, one of the core benefits of grass fed beef is the quality of fat (e.g. omega3 to omega-6 ratio) obtained, which doesn’t apply to bones so much.

N.B. Having a little meat left on the bones is a non-issue, given that you’ll be straining the contents at the end.

Bone Broth Cooking Steps

  • Place bones in a pot
  • Add a tablespoon of vinegar (to help bring out the nutrients)
  • Season with salt, and optional extras like pepper or herbs
  • Cover with water
  • Bring to the boil, then reduce heat until simmering
  • Initially there may be some fat build up on the surface, which can be skimmed off
  • For chicken bones, cooking overnight is often enough time, up to 24h is not uncommon
  • For beef bones, overnight is possible, but due to being stronger than chicken bones, beef often needs a bit longer (say 24 hours)
  • When finished, strain the broth into containers
  • Let cool and then refrigerate or freeze what you don’t plan to immediately consume

See YouTube for a good beef broth example video and a good chicken broth example video.

Shop Bought Bone Broth

Whilst shop bought bone broths generally aren’t as good, or nutritious as a home made broth, they’re a good option when time is limited. Especially when the core focus here is to adhere to the fasting protocol itself. The bone broths are just a component of the overall plan.

Two off the shelf broths with good reviews are Pacific Organic Chicken Broth & Kettle & Fire Beef Broth. Pacific’s version is more affordable, but has a bit less marketing hype behind it.

The above is just a tiny snapshot of Jason’s book. The full thing contains vastly more content, including discussion of:

  • Disease prevention
  • Tips for fasting and intermittent fasting
  • + more!

You can find the full version of The Obesity Code on Amazon.com, along with Jason’s other bestsellers’ The Diabetes Code and The Complete Guide to Fasting.

To discuss the Obesity Code Diet further, you can join this Facebook Group.

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See Post Sources Below:

  1. Vinegar dressing and cold storage of potatoes lowers postprandial glycaemic and insulinaemic responses in healthy subjects – Leeman M (2005)

Posted by John Alexander

Note: Not a Medical Doctor or PhD. I'm a researcher and writer, with a focus on the subjects of health and longevity. My intent is to write about scientific research in an accessible, understandable way. If you believe something I've stated needs a reference, and I haven't done so, please let me know in the comments.

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Howard Richard Hardy Powell
Howard Richard Hardy Powell
3 months ago

My 42 year old step-son who is obese has embarked via the NHS (Britian) a fat reducing diet during the course of which he has constantly felt hungry. Although he has lost weight he has been told by the NHS Team that eventually, when reaching the required weight he will be eligible to have a medical operation for the implementation of a “Gastric Band”. I have about 2 weeks ago bought Dr. Fung’s book the “Obesity Code” which I have found excellent although I’m still reading my way through it. Question:- If my Step Son (Paul) does have a “Gastic… Read more »

Jenny
Jenny
8 months ago

How many calories are in the bone broth?
I have one of Dr. Fung’s books and can’t find it there or elsewhere.

Bonnie
Bonnie
8 months ago

John Alexander! Are you kidding me?! You are amazing. One of the most balanced unbiased writers I’ve come across! Thank you for what you do. Next–》Are you kidding me again! You intelligently answered every one of the posted questions for pages and pages! Unheard of. You’re amazing. Finally! I was doing keto before keto was a thing. Then I did carnivore before it was a thing, then I was fasting before all of this and at every change people got angry and told me I would die. But at every change I felt better and better and learned more and… Read more »

Lyn
Lyn
9 months ago

Thank you for this – I listened to the audiobook about a year ago and was hazy on the key points. This was extremely helpful!

Julia
Julia
1 year ago

Hi John,

Are you familiar with HUEL Black Edition? I am thinking of using this and starting fasting, as I am vegan so wouldn’t be able to follow much of the food planning is quite meat and dairy heavy. I am really glad to have found this as have always thought small and regular eating was best!! Now I know where i’ve probably been going wrong all my life ha!

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