Chapter 16 | Carbohydrates & Protective Fiber

Sep 24, 2019


Check out a replay of the Facebook LIVE discussion HERE

You Will Learn

  • Why processed and refined carbohydrates are bad for your waistline. 
  • Why fiber is considered the antidote to starch and sugar. 
  • My three rules for choosing good carbohydrate sources. 


About Dr. Fung, Author of The Obesity Code and The Diabetes Code

Dr. Jason Fung is a medical doctor, nephrologist by trade, who specializes in kidney disease, type 2 diabetes, and obesity. He acknowledged that traditional medicine wastes time and resources attempting to treat symptoms of disease, rather than the cause of disease. 

You can purchase The Obesity Code book HERE.


Overview of the Book

Here is the outline of the book. This post covers chapter 16 in Part 5. 

Part 1: “The Epidemic,” explores the timeline of the obesity epidemic and the contribution of the patient’s family history. It highlights the underlying causes of obesity. 

Part 2: “The Calorie Deception,” reviews the current caloric theory in depth and highlights the shortcomings of the current understanding of obesity. 

Part 3: “A New Model of Obesity,” describes how hormones are involved in the development of obesity. These chapters explain the central role of insulin in regulating body weight and describe the vitally important role of insulin resistance. 

Part 4: “The Social Phenomenon of Obesity,” dives into childhood obesity and why obesity is associated with poverty. 

Part 5: “What’s Wrong with Our Diet?,” explores the role of fat, protein, and carbohydrates, the three macronutrients, in weight gain. In addition, it examines one of the main culprits in weight gain - fructose - and the effects of artificial sweeteners. 

Part 6: “The Solution,” provides guidelines for lasting treatment of obesity by addressing the hormonal imbalance of high blood insulin through proper nutrition, sleep, and stress management. 


Why Processed & Refined Carbohydrates are Bad for Your Waistline

To review, there are three main types of carbohydrates I discuss: 

  1. Starch - Starch is many molecules of glucose (a type of sugar compound). Essentially starch is very similar to sugar. 
  2. Sugar - There are different types of sugar. See this article for a full explanation. 
  3. Fiber - The non-digestible part of food. See this article for more information. 

Modern-day processing of carbohydrates, namely wheat, strips the wheat bran of everything except the starch. The protein, fat, fiber, and vitamins are removed. What’s left is a fine white powder (flour) that is absorbed very quickly by the intestine. 

The increased rate of glucose absorption causes a rapid rise in blood sugar, and thus blood insulin levels to move that sugar out of the blood and into tissues where it can be used for energy or stored as fat.

Whole wheat and whole grain flours retain some of the nutrients but are still rapidly absorbed and cause a blood sugar and insulin spike. That is why wheat bread is not much better for you than white

Remember, it is persistently high levels of insulin that increase the body set weight and cause us to gain weight, slowly but surely. If you have switched to eating whole grain bread vs. white, or using whole grain flour vs. white, that’s a good first step but I would encourage you to move beyond that and not include flour or flour products in your diet on a regular basis. 

There are some flour alternatives like coconut flour and almond flour that have a lower blood glucose and insulin response that may be a good alternative for you to use. 


Why Fiber is Considered the Antidote to Starch and Sugar 

Dr. Fung explains on pages 182-183 that fiber is an “anti-nutrient”. While most substances like proteins, fats, sugar, and starches add something to the body for nourishment, fiber’s benefits come from its ability to reduce absorption and digestion of starches and sugars. Fiber subtracts rather than adds. That is why carb counters who track their net carbs can exclude fiber. Net carbohydrates = total carbohydrates - fiber. 

“Soluble fiber reduces carbohydrate absorption, which in turn reduces blood glucose and insulin levels...because insulin is the main driver of obesity and diabetes, its reduction is beneficial.” - p. 182

Dr. Fung goes onto use an analogy that uses fiber as the “antidote” to the starch and sugar - which in this analogy, is the poison. Remember carbohydrates, even sugar, are not actually poisonous, we are just using those words to recap this analogy. 

With the exception of honey, most carbohydrates that are found in nature...fruits, vegetables, nuts, seeds, grains, also have fiber in them. This fiber naturally slows down the digestion of the rest of the carbohydrate in that food, thus lowering the overall glucose and insulin effect. Protein and fat in some carbohydrate sources have a similar "slowing down" effect for digestion and absorption. 

Many traditional societies have a very high carbohydrate diet but their carbohydrate sources come from whole, unprocessed foods that also contain a lot of fiber, thus slowing the digestion and reducing the impact of the carbohydrates on their waistline. One study found that people who ate the most fiber were the least likely to gain weight. 

Other ways that fiber can assist in weight loss include: increased bulk in the stomach, thus reducing hunger and overall food intake, slowed absorption of food so your body can get more nutrients out of the food, improved bowel movements. 


Three Rules for Choosing Carbohydrates

This is not in Dr. Fung’s book, I just think these rules are helpful when I’m at the grocery store picking out food. These rules stand alone from each other. For example, your broccoli (rule #1) does not need to be cooked (rule #2). 

  1. They need to be refrigerated or go bad quickly (fresh fruits and vegetables). 
  2. They require cooking. For example: beans which you can find pre-cooked in a can; whole unprocessed or minimally processed grains (quinoa, barley, oats, etc). 
  3. They just have one, whole ingredient so shouldn’t need a food label. 


Bottom Line

  1. When trying to lose weight, it’s very important to optimize your nutrition to lower your overall insulin levels. One of the best ways to do that is to reduce the sugar and refined carbohydrates you are eating. 
  2. Fiber, both soluble and insoluble, is important for overall health and can assist in weight loss efforts by helping you feel fuller, reducing the rate of food absorption thus lowering the glucose and insulin response of that food, and keeping your bowels regular and healthy. 
  3. When choosing healthy carbohydrates, the more fiber the better. The more unprocessed the better. Follow my three rules for a common-sense approach for choosing healthy carbohydrates. 



  1. Chapter 16. (2016). In J. Fung, The Obesity Code: Unlocking the Secrets of Weight Loss. Vancouver: Greystone Books. 

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