Review and Summary: The Obesity Code

The Obesity Code book cover
The Obesity Code Book Cover

Dealing with overweight body and find a way to lose it is hard. By the time we find the way, we find the harder challenge to lose more weight or even just to maintain it.

As a doctor who has experience of treating patients with type 2 diabetes, Jason Fung believes that the reason we cannot lose weight is because we do not have the sufficient knowledge about obesity. Thus, Fung would like to share his framework to understand and deal with it in The Obesity Code. In this book, Fung informs the reader that the issue behind obesity is not laying down critically on caloric imbalance. Fung counts on hormonal problem as the main suspect of obesity.

We didn’t lack resources or willpower; we lacked knowledge of and a framework for understanding obesity.

Jason Fung, MD, The Obesity Code

Here, I summarize the most outstanding insight and tips from The Obesity Code.

What we know about obesity all this time is mostly wrong

1. Counting calories is not make sense

Most people holding on tightly on basic formula in diet: deficit calorie. Logically, decreasing our calories intake works only if the number of calories out remains constant. Unfortunately, it is impossible to count daily the ways our body spend calories. Calorie expenditure depends on basal metabolic rate (breathing, maintaining body normal function), thermogenic of food, our activity, and exercise that we barely can count it accurately.

We have to understand that our body is designed to survive and it is capable to outsmart ourselves. To keep up with low calories intake, our body will reduce body heat, heart rate, stroke volume, blood pressure, and even cognition that we barely can concentrate.

To make it worse, our body sends us signal to eat in order to get more food and keep up with the lost weight. Study revealed that a year after initial weight loss the level of satiety hormones were decrease and the ghrelin hormone stimulates hunger even after more than a year after initial weight loss.

Caloric reduction does not result in lasting weight loss.

2. Stop judging calories in food equally

The most fatal assumption is we see calorie in all type of food as equal. We close our eyes on how the food affects our body. For example, eating a piece of cake will trigger a spike of blood glucose while olive oil will not.

3. Obesity is hormonal-driven, not a caloric issues

We thought that we can control when to eat and when to stop. We are not aware of satiety hormone that sends signals of fullness.

We also thought that the expansion of our body is rely on our food intake. We do not understand that we have leptin to regulate fat growth, adiponectin, and many other hormones to regulate fat stores.

4. No correlation between exercise and obesity

Medical research even the long-term ones have shown that exercise has less or no effect on weight loss. Just like what happens in reducing calories in reduces calories out, our body will compensate by running the principle of homeostasis: body tries to maintain a steady state.

Furthermore, we have to acknowledge that we cannot overexercise as it will over stress our body.

Still, exercise is important to build a fit body so keep moving!

What really causes obesity?

Insulin, the main culprit of obesity

Several studies use drugs which triggers the body to produce insulin confirms the correlation of insulin to body weight gain.

How does insulin can be the main culprit of obesity?

Brain, liver, and muscle are the main compartment of insulin and resistance in one of them does not influence the other.

Bad food intake → develop insulin resistance in liver only.

Lack of exercise → trigger insulin resistance in the muscle.

Having bad diet and not exercise regularly → overall high insulin levels.

By the time high insulin levels arrive at the brain → the insulin holds its full effect to raise body weight’s set → persistence → insulin resistance → high hormonal levels and steady stimulus of insulin.

What triggers our body to have insulin resistance?

The higher insulin levels → the greater the insulin resistance → the higher the insulin levels → vicious cycle → the longer it lasts → the worse it becomes → significant insulin resistance → develop into high insulin levels that are independent of diet → at this point, no matter the alteration of your food intake into the healthy ones, the insulin resistance would still exist and the obesity stays.

Why is obesity that has been last so long is hard to treat?

Because time frame matters. Insulin resistance is time dependent and independent of diet. The longer insulin resistance stay in our body, the effort to get rid of it is getting harder.

Homeostatic mechanism makes losing weight hard

Homeostasis is the fundamental principal in biology where it defend our body against transformations and remain on the set point. In terms of body weight, the body set weight is defended, either up or down. No wonder that losing weight is so difficult.

So, to answer the mystery of dealing with obesity, we have to understand how to beat homeostatic mechanisms and bring it downward.

What to do to lose weight?

  • If you are not hungry, it means that your body is telling you that it is not eating time yet. So, stop looking at your fridge and don’t eat!
  • Reduce the consumption of added sugar (Read: the unhealthiness of sugar, why obesity in Asian stays low while high consumption of white rice, diet soda does not work)
  • Make breakfast optional (explanation). If you still want to have a breakfast:
    • Food recommendations: traditional and greek yoghurt, whole oats and steel-cut oats, scrambled eggs, plain sparkling water, beverages without sugar (coffee, tea, slices of lemon, orange, or cucumber as a refreshing addition), bone broth (explanation),
    • Avoid: instant oatmeal, beverages with added sugar
  • Reduce refined grain consumption.
  • Take protein in moderate amount
  • Raise natural fat intake
    • Olive oil, butter, coconut oil, beef tallow, leaf lard, avocado are recommended.
    • Mediterranean diet is recommended.
  • Escalate protective factors consumption
    • Fiber intake → reduce the insulin-stimulating effects of carb → main protective factors against obesity
    • Example: konjac, vinegar
  • Doing The Paleo Diet
    • consuming foods that only available in ancient rimes or Paleolithic
    • Only eat fruits, veggies, nuts, seeds, spices, herbs, meat, seafood, and eggs
    • No processed foods, added sugars, dairy, vegetable oils, sweeteners, and alcohols
  • Doing The Low Carb, High Fat or Low Card, Healthy Fat (LCHF) diet
    • Objective: focus on real foods
    • allow dairy products
    • High carbohydrate content in fruits → strict on fruits consumption
  • Fasting regularly
    • fasting → break insulin resistance → lose weight
    • Fasting is different with starvation. Fasting is the absence of food for a certain period of time while starvation is the involuntarily absence of food.


Is all sugar unhealthy?

There are four types of sugar:

  • Glucose
    • type of sugar found in blood
    • directly stimulates insulin
    • can be stored in the body in various forms, such as glycogen in the liver.
    • if glucose stores run low → liver make new glucose via gluconeogenesis
  • Fructose
    • stronger correlation to obesity and diabetes than glucose
    • Small amount of fructose in natural fruit.
    • Problems: high-fructose corn syrup in almost every processed foods
    • As a main sugar in the fruit it has low glycemic index → mild rise insulin levels compared to glucose → looks healthy, but not that perfectly healthy, because:
      • Excessive fructose turns into fat in the liver → insulin tries to force more fat and sugar → higher levels of insulin to process the same amount of food and energy into a fatty liver → body resistant to the effort of insulin → insulin resistance at the liver → liver try to expel the sugar back into circulation → continously high insulin levels are also required to keep it bottled up in the liver]]. If insulin levels start to drop, the stored fat and sugar comes whooshing out. To compensate, the body keeps raising its insulin levels → insulin resistance leads to higher insulin levels.
  • Sucrose
    • table sugar
    • mix of glucose and fructose
    • triggers insulin release in short- and long-term → worse than glucose
  • Lactose

Back to What to do to Lose Weight?

What about most Asians who ate a diet based on white rice yet obesity remained quite rare?

It is because Asians’ sucrose consumption was low which means the risk to develop insulin resistance is also low. Once sucrose consumption started to increase → began to develop insulin resistance. Together with their original high white rice (carbohydrate) intake, this was an ultimate way for the diabetes disaster Asia faces right now.

Back to What to do to Lose Weight?

Diet soda is not for diet.

Diet soda is using artificial low-calorie sweeteners. Unfortunately, the one that drives weight gain and metabolic syndrome is insulin, not calories. Studies showed that artificial sweeteners:

  • Increased insulin much higher than table sugar.
  • Brain senses sweetness with less calories → overcompensation and increase appetite and cravings.
  • No significant difference to lose weight.

Back to What to do to Lose Weight?

Breakfast is not important.

Our body is much smarter than we thought because it has “cooked” breakfast automatically in a phenomenon called The Dawn Phenomenon:

  • Before we wake up in the morning, circadian rhythm jolts us with a combination of growth hormone, epinephrine, cortisol, and adrenaline → stimulates the liver to make new glucose → wake us up.

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Bone broth is healthy

  • Long simmering time → releases minerals, gelatin, and nutrients.
  • Addition of vinegar → leach some of the stored minerals.
  • High in amino acids.

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What is glycemic index?

The glycemic index measures the elevation in blood sugar in response to a standard portion of food. It does not count protein or fats at all because they do not raise glucose.

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Why is the glycemic index diets fail?

Glycemic index diets foundation relies on a misleading assumption where insulin mirrored glucose response. The truth is we could decrease the glucose response without necessarily decrease the insulin response. And what really matters is insulin response.

Back to What to do to Lose Weight?

What is insulin index?

The insulin index measures the escalation in insulin in response to a standard portion of food. It will be surged by refined carbohydrates and dietary proteins.

Back to What to do to Lose Weight?

Author: Jason Fung, MD

Publication date: 1 March 2016

Publisher: Greystone Books

Number of pages: 315 pages


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