Not since I first read Gary Taubes’, Why We Get Fat, have I been so informed by a book on how fat is metabolized. This one is particularly significant because it’s written by a woman, Sylvia Tara, who has a PhD in Biochemistry. And lucky for us, she is a great storyteller. “Tales of the Liposucked” was a pretty enlightening section. It’s an easy read–only 7 hours of audio and 200 pages.
The Secret Life of Fat was published in February 2017, so the research cited is both current as well as thorough; included are numerous studies and authorities that Taubes and the other authors whose books appear on this site have also referenced. There is a fairly conclusive body of research that has emerged on this topic.
Fat is vital–it surrounds all of our cells giving them structure. Our brain is especially dependent on fat. Myelin (80% fat) insulates nerve cells so they can properly function (p. 23), and leptin (a hormone fat produces) helps increase the size and function of the brain (pp. 56-57). Fat can act as a messenger molecule to signal our bodies to do certain things such as fight inflammation (p.24), strengthen our bones (p. 23), and even enhance our immune system (pp. 57-60).
Here is an overview of the book’s contents:
Section 1-All About Fat
Includes chapters, “Fat Does More Than You Think”; “When Good Fat Goes Bad”; and “How Fat Fights to Stay on You.”
Section 2- It Is Not Only Food That Makes Us Fat
Includes chapters, “I Blame My Parents–Genes in Obesity”; “I Am Woman, I Have Fat”; and “Fat Can Listen.”
Section 3- So What Is The Solution?
Includes chapters, “Fat Control I”; “How You Can Do It”; “Mind Over Fat”; “Fat Control II” and “How I Do It.”
The most important parts of the book, from my perspective, are in the first two sections. If you are interested in what happens to your body as you age or why something that works for one person doesn’t work for you, this book makes clear the various ways in which fat is stored and utilized by different bodies. And if you ever thought you were having a hard time shedding pounds, then the last third of the book will provide assurance that you are not alone.
“Metabolism is far more complicated than the simple arithmetic of a calorie in, a calorie out. We are not pure calorie-burning machines. We are an intricate system of biology, hormones, genetics, and bacteria processing nutrients individually.” (The Secret Life of Fat, p.6).
A few of the points made by the author include:
- Fat is not just fat–it is currently considered “a dynamic and interactive endocrine organ” that has a major influence over our health and well being (p. 24).
- There are different kinds of fat: white fat stores energy, brown fat burns energy for heat by using a special protein, and now beige fat has been discovered–studies indicates that beige fat may be able to be converted to brown fat during exercise (pp. 20-21).
- When we are infants, most of our fat is brown fat, keeping us warm and insulated. As we age more fat becomes white fat and at puberty even more fat is produced. In order to bear children women have to have the right amount of fat, “not too much or too little.” As people reach their forties sex hormones wane, and between the ages of 50-60 controlling fat becomes the most difficult (pp. 147-148), due largely to the change in hormone levels.
- Fat cells have receptors for hormones that are designed to bind to insulin, as well as other hormones that tell fat to release energy. Once insulin is bound to a fat receptor, however, the fat cells act differently and change to produce more fat (pp.148-149).
- Hormone levels are affected by what we eat as well as the quantity of food consumed. Eating sugary foods reduces growth-hormone levels and also makes it harder to burn the extra fat (p.157).
- Why do we eat more after a night of little sleep? Ghrelin levels are elevated (p. 92-93). Ghrelin is a hormone that is produced in the gut and stimulates appetite (p. 88).
- Fat can come back even after surgery to remove it. Studies have shown that, without exercise after liposuction, it can return as visceral fat (under the organs) due in part to a slower metabolism (p. 91-92).
- Genetic differences accounted for about 50% of the variation in the ability to lose weight by exercise when calorie intake was controlled in a research environment (study on identical twins by Claude Bouchard, 1994) (p.125).
- Exercise can increase certain hormone levels resulting in more fat being burned and increased lean muscle mass, but intense exercise can contribute to offsetting appetite triggers. Certain exercise will cause people to consume all the calories burned, and more. One doctor the author references thinks starting out a new fitness program with an hour of walking a day will help burn extra calories without increasing appetite (pp. 156-157).
In conclusion, a solid understanding of the biological factors at work in the body will help with decision making when it comes to food choices. Knowing the role that hormones (insulin in particular) and genes play in determining both the shape of your body and the numbers on the scale may ease some anxiety. Most everyone is challenged by the fat that appears at various times of life. The Secret Life of Fat should reinforce the importance of finding a healthy level of fat for you.