The Secret Life of Fat: The Science Behind the Body's Greatest Puzzle
By Sylvia Tara
Review by David Wineberg
The title couldn’t be more perfect. Fat is a universe unto itself, and we are only now discovering how it runs our bodies. The book is as dramatic as the title, and the chapters are filled with case studies of individuals and research findings, and both from all over the world. It is also very personal, inspired by Tara’s own combat with fat. Informed by her own findings, she beats her fat at its own game.
Tara has a lovely description of fat: glucose is like cash, glycogen (chains of glucose) like a checking account, and fat is a certificate of deposit. There are three kinds of fat – white, beige and brown. White is the classic, energy store. Beige waits for signals to change to brown, which is saturated with mitochondria and burns energy instead of storing it. This, for obvious reasons, has become an obsession for research.
-Like any other organ, fat will fight for life. Constant diet changing, losing and regaining a few pounds, only makes it tougher. It has the communication and receptor tools to keep itself in control. It manipulates the brain and participates in brain signals.
-Fat signals the body for angiogenesis – it orders up new veins and arteries to approach it, in order to feed it, just like a tumor.
-Fat knows when there is too much of it and signals the body to manufacture cytokines – inflammatories – the usual first line of defense.
-Fat is an endocrine organ – it produces hormones (leptin) that latch onto the brain’s hypothalamus and tell it to be hungry – or not.
-By reducing leptin levels, remaining fat makes people feel hungrier than they were before reducing.
-Fat circulates adiponectin which helps clear the blood - of fat. Those with high levels can be very fat and perfectly healthy. Hard exercise increases levels.
-More than 50% of cells in the fat of the obese are immune cells, vs 5% in the fat of the normal or thin.
-Fat resurges by lowering energy levels, so dieters have to work harder than normal to keep weight off. Only consistent, hard exercise overcomes the return of fat - even following liposuction.
-Half a pound of fat can contain 50 million stem cells, used to rebuild muscle, bone and organs throughout the body. Doctors are quickly learning to repurpose them.
-Hard exercise overcomes genetic predispositions to fat and weight in most cases.
Chapter 8 is all about how women’s bodies deal differently with fat. Their fat is a better kind (subcutaneous vs visceral), but there is more of it, and it takes them disproportionately more effort in the gym and less at the table to achieve the goals men see more easily.
There is a fascinating analysis of sumo wrestlers, those hugely fat men whose sole job in life is to push other obese opponents out of the ring. The surprise is their blood levels are excellent, and they are extraordinarily healthy – as long as they keep to the training regimen and diet. Once they retire, they quickly slide into fat hell.
Oddly, the chapter I was expecting – how do people with no fat and extreme, reduced calorie diets – fare – is missing. In animal studies, such diets extend lifespans and energy levels dramatically. So is fat really necessary, or are we better off without it altogether? No mention in The Secret Life of Fat.
Tara’s book is a lovely combination of the emotional and the scientific, the personal and the universal, narrative and science. It is lean and muscled and terrifically readable.
Editor's note: This review was has been reposted with permission of David Wineberg. Like what you read? Subscribe to the SFRB's free daily email notice so you can be up-to-date on our latest articles. Scroll up this page to the sign-up field on your right.