Burn: New Research Blows the Lid Off How We Really Burn Calories, Lose Weight, and Stay Healthy by Herman Pontzer PhD is a great resource to learn about metabolism
Introduction
The book Burn: New Research Blows the Lid Off How We Really Burn Calories, Lose Weight, and Stay Healthy by Herman Pontzer PhD is a book about the science of metabolism. According to a webpage on the author from Duke University he is a Professor of Evolutionary Anthropology and Global Health. He studies how ecology, lifestyle, diet, and evolutionary history affect metabolism and health. He and his team did research on the Hazda, who are a present day hunter gatherer group in Tanzania, and the results are fascinating. I was introduced to this book through a shocking article that said exercise doesn’t work for weight loss according to the author’s studies. I was skeptical but the author being a scientist doing studies on us and other primates made me curious. I read the book and the research shows exercise doesn’t work for weight loss as we may be expecting. That is not a reason to not exercise because it has a lot of other benefits. It is surprising how it all works and it is discussed in some details in this article with more details contained in the book.
I would divide the learning from the book into 4 areas. These are learning about metabolism, findings about our ancestral diets and how different diets may be working for weight loss, discussions on the science of exercise when it comes to weight loss and health from a metabolic perspective and interesting history and insights about us, other animals and mitochondria. More on these below.
Learning about metabolism
This book is about metabolism and it delivers in this aspect. It explains the scientific progress made in the field of metabolism in a way that it easy to understand. You can find simple explanations for concepts ranging from different macro nutrients, digestion, absorption, what metabolism is, how it is measured etc. Having a basic understanding of these concepts help in having a better sense of what is going on in our own bodies and to better understand related topics.
The book explains metabolism as the work cells do. These include transporting molecules in and out of the cell walls and making compounds. There are different ways to measure metabolism such as heat produced, oxygen consumed and carbon dioxide expelled and the doubly labeled water method. The book has details on how these measurements are done and the explanations for how it works. If you are not familiar with these concepts don’t worry too much. I didn’t have any knowledge on this topic before and thanks to the simple explanations in the book, I could understand them, at least at a high level.
Findings about our ancestral diets and how different diets may be working for weight loss
There are interesting findings and observations about the diet of our hunter gather ancestors and present day hunter gatherers like the Hazda discussed in the book. The author notes that the Hazda consume tubers and honey, and carbohydrates make up a majority of their caloric intake. There is also some evidence shared about our ancestors eating a carbohydrate heavy diet. They found it from the plaque from the fossils which I found really interesting. Anyway we cannot know for certain what our ancestors ate but we could say with some confidence that they ate whatever they could find. The author shares the problems with the claims of our ancestors eating a certain composition of macro nutrients like in a paleo diet. Imagine our paleolithic ancestors throwing out a 22.6% eaten apple because their daily quota of 5% carbohydrates is reached. It is very unlikely.
The book has some discussions on the science of weight loss when it comes to low carb or keto diet. The author says that the way these work is by reducing the total number of calories consumed or by preventing over eating. Our bodies are designed to store excess energy and if there is no excess energy then there is nothing to store. If we consume less than what we need then our body will have to use our stored energy. That results in weight loss. There is more to this topic and it is discussed in detail in the book. Along with that there is discussions on certain biological aspects of our bodies working to maintain weight, control appetite etc. It was good to know these things through the metabolic angle presented in the book.
The science of exercise when it comes to weight loss and health from a metabolic perspective
Exercising for weight loss may not give you the results you are expecting. The book details on a model of metabolism called constrained daily energy expenditure model. It says that our daily energy expenditure is maintained at a narrow range. In other words the amount of energy we can spend is tightly controlled. If we spend more energy on exercise then there is less energy for other things. For example, when there is more energy demands from exercise then our body could dial back on things like inflammation which keeps the total energy spend within a certain range. So the more exercise you do doesn’t necessarily mean the more calories you burn. The calories you burn from doing exercise may not be that significant too. The book gives examples for the amount of calories you burn from different activities and one of them is that the calories burned from walking 10,000 steps is just as much as in a can of cola. A can of cola can be consumed in under a minute whereas 10,000 steps take around one and a half hours. Because of these factors exercise is not a reliable tool to lose weight. That doesn’t mean we shouldn’t exercise. Exercise has many benefits for various aspects of health. As the constrained daily energy expenditure model predicts if more energy is spent on exercise then less energy is available to spend for things like inflammation, stress or reproduction. Our body could reduce inflammation, reduce the magnitude of the stress response or suppress our reproductive system to account for it. These things are generally good even the suppression of the reproductive system. The book notes that exercise is effective in decreasing the risk of cancers of the reproductive system like breast cancer and prostate cancer. It is in part because it keeps reproductive hormone levels in check. In short, exercise is great for health and longevity even though it may not be the best tool to lose weight. The best tool to lose weight is through your diet.
Even though exercise is not that effective for weight loss, it helps you maintain weight loss once you are able to lose it. The book mentions a study of obese policemen in Boston. They were divided into two groups following different weight loss programs for two months. One group followed a diet only program and the other followed a diet plus exercise program. The study found no difference in the amount of weight loss between the two groups. An interesting observation after the program was that the group who did diet plus exercise or the members from the diet only group who started exercising were successful in keeping the lost weight off. The people who didn’t exercise after the weight loss program gained all their weight back. This is another benefit of exercise discussed in the book.
Interesting history, stories and insights about us, some other animals and mitochondria
The book includes some history and facts about how we differ from other primates such as having a much longer life span and the differences in metabolism between the different species. We humans share food or other resources and help each other more than other primates and it is noted as playing a role in how our metabolism evolved. Like for example the slow development of our babies, without somebody’s help like from their parents they won’t be able to fulfil their energy requirements on their own. Apart from that you can find discussions on metabolic strategies for example rats going through starvation conserving reproduction over other areas in contrast to us who dials down on reproduction. You will also come across some history of mitocondria. I have found this in other books about mitocondria being engulfed bacteria but the story of the discovery shared in the book is interesting. There are also accounts of life of the Hazda and the authors journey as a scientist. One story that comes to mind is that of a Hazda boy, who didn’t like school, walking 3 days through the forest back to his home. It is scary what the boy did but he just recalls it like yeah I walked back home, what’s the big deal. In short I found many things in the book like evolutionary history, stories of how we discovered something, accounts of real life etc interesting and sometimes even entertaining.
Conclusion
This books gave me a lot of insights into how our bodies work. It is easy to read, simple and entertaining. I would recommend it to anybody interested in metabolism. I would also recommend it to you if you are trying to lose weight or is following a strict “ancestral” diet. There are chances that you could have come across questionable claims about certain aspects of our diet and I believe this a great resource to bring more clarity to those areas. Additionally if you are spending money on metabolism boosting supplements, teas etc, I would highly recommend this book to you.
Book discussed
- Burn: New Research Blows the Lid Off How We Really Burn Calories, Lose Weight, and Stay Healthy by Herman Pontzer PhD