Friday, July 13, 2018

Book Review: The Obesity Code

Next up for review is The Obesity Code: Unlocking The Secrets Of Weight Loss. The author, Dr. Jason Fung is a Canadian Nephrologist.

This book theorizes that overeating and a sedentary lifestyle have little to do with the obesity epidemic. Dr. Fung believes that obesity is caused by high levels of insulin. The book includes sections on the origins of the obesity epidemic, why overeating and exercise are not that important, Dr. Fung’s new model of obesity, what is wrong with our diet and the solution, which details when to eat and what to eat. The book is 315 pages long and very well written. I enjoyed reading it.

5 Things I Really Liked About The Obesity Code
1) Dr. Fung uses a lot of research to back up his claims. While he does make a few errors in interpreting the nutrition literature, this is a refreshing change in comparison to most best-selling weight loss books.

2) I agree that insulin levels have a lot to do with weight gain. This is a major reason why I recommend a low glycemic load approach for weight loss with my own clients.

3) I totally agree with the restriction on snacking. Even small amounts of extra calories consumed daily can add up to significant weight gain over time. Three balanced meals a day are all we need.

4) I totally agree that added sugars and refined carbohydrates are major causes of weight gain for most of us. Eliminating them needs to be a big part of any weight loss strategy.

5) I like the section on the importance of sleep in weight loss. The research is really beginning to back this up. Short sleep appears to decrease leptin levels and increase ghrelin levels. Both hormones have a lot to do with your ability to lose weight.

5 Things I Didn’t Agree With in The Obesity Code
1) I do not understand Dr. Fung’s theories on exercise. Here is an example:
Page 50: “Physical activity has virtually no relationship to the prevalence of obesity.”
Many studies show that physical activity is a big part of the strategy for those that are successful losing weight. A white paper on my website summarizes a number of these studies (you can find it here).

Page 51: “Exercise has not decreased since hunter gatherer times.” Does Dr. Fung really believe that a sedentary office worker that drives to work and sits in front of a computer all day gets as much physical activity as a caveman who had to walk everywhere he went and hunt and forage for every calorie he ingested?

Page 54: “Exercise has many benefits, but weight loss is not among them”. Strangely, right after this quotation, Dr. Fung cites a randomized trial showing that subjects who exercised 5 times per week lost an extra 10 pounds over 10 months when compared to those that did not exercise.

Generally, exercise by itself is not enough to hit your weight loss goals, but in combination with dietary change, exercise plays a critical role.

2) Similar to his view on cardio, this book makes absolutely no mention of the importance of resistance training. Lifting weights decreases the loss of lean body mass as we lose weight. This makes it much more likely that weight we lose will stay off. Building muscle with weight training increases metabolism since muscle burns three times as many calories as fat. Burning more calories per day makes it much easier to lose weight over the long-term.

3) Dr. Fung believes that saturated fat is harmless. He recommends a regular consumption of butter, coconut oil, full fat dairy and beef tallow. He cites a reference from the Nurses’ Health Study to show that total fat is not associated with risk of heart disease (New England Journal of Medicine, 1997; 337:1491). While this is accurate, the rest of this study shows that the type of fat is very important. Saturated fat increased risk of heart disease in this cohort, while mono- and polyunsaturated fat decreased risk. Ironically, after citing this study, Dr. Fung says that saturated fat is fine and that vegetable oils have a negative impact on health. I am not quite sure how he mixed this up. Either way, saturated fat is to be avoided, it increases risk of heart disease.

4) I didn’t agree with the alcohol recommendations in The Obesity Code. Dr. Fung says up to 2 drinks a day are fine. It is my opinion that 14 drinks a week will seriously impede weight loss in both men and women. I have my clients cut down quite a bit on the alcohol if they are trying to lose weight.

5) This book recommends fasting 24 to 36 hours, two to three times per week. I don’t think this is a good idea. In the last year or so, I have blogged on 3 separate studies that examined fasting and were published in top journals. The results were not favorable. Among the findings:

-Drop out rates were higher in those fasting compared to more modest calorie restriction. This means it is much harder to stick to a fasting weight loss plan.

-There was no difference in weight loss between those fasting and those moderately restricting calories.

-LDL cholesterol significantly increased in subjects fasting.

-Several studies showed glucose dysregulation when fasting.

-Subjects fasting had an increase in inflammation.

-Subjects ate significantly more calories than normal the day after fasting.

-Energy expenditure decreased when fasting. 

(You can find these studies, here, here and here.) 

In The Obesity Code, Dr. Fung gives a number of tips when fasting.  Here are a few:

-Take cinnamon and eat chia seeds to reduce hunger.

-Drink salt water when you get dizzy.

-Take a magnesium supplement when you get muscle cramping.

-Drink salt water when you get headaches.

-Take Metamucil when you get constipated.

-Take a multivitamin because you won’t be getting any micronutrients on fasting days.

Maybe it’s just me, but having to do all of these things leads me to believe that fasting is neither a healthy or normal way for the human body to lose weight.

Is The Obesity Code Worth Reading?
Absolutely! It is important for me to read nutrition books that differ from my own personal philosophy. This book makes a lot of really good points. Levels of insulin have much to do with obesity. Limiting sugar and refined carbs are a huge part of the solution. Adequate sleep and limiting snacking are also big players. I would just add a bit to this good advice, notably; lift weights at least twice a week to build muscle, daily cardiovascular exercise is a huge part of weight loss, there is no need to fast, and lastly be sure to limit saturated fats and substitute them with more healthy vegetable fats.

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