Fructose and the fat switch

By John DiTraglia

I just listened to a Petter Attia podcast with Dr. Richard Johnson who explains the controversial role of fructose in the epidemic of obesity. (1) This story of fructose is a side bar to the sugar wars that rage.

Rick Johnson MD is a nephrologist. In 2012 he wrote a book called The Fat Switch.(2) This wide ranging story starts by examining the natural history of many species that hibernate or migrate amazing distances. These ordeals involve not being able to eat for long periods and require having to get fat each year. Besides getting fat many of these creatures actually get type 2 diabetes and fatty livers on purpose. He reasoned that there must be a switch that allows these otherwise lean animals to be able to get fat periodically.

Then there is the amazing story of how the ancestors of the great apes who had migrated out of Africa into Europe many thousands of years ago developed the uricase mutation to cope with long periods of famine each winter when Europe was going through an increasingly cold ice age. This uricase mutation was a fat switch and allowed them to get fat in the season when food was more plentiful. Then some of them managed to migrated back into Africa before going extinct in Europe. In Africa these uricase mutants eventually evolved into the various modern great apes like humans in response to other geographical phenomena and stresses and then migrated out of Africa again and etc….

Dr Johnson next explores the ancient history and not so ancient history of human evolution through farming and sugar farming and diabetes and obesity. Finally he ranges far afield with more speculative stories about horse diseases and lead poisoning and gut bacteria and sugar addiction and attention deficit-hyperactivity disorder and food allergies among others. Just the 50 pages of classic references make this book a valuable resource.

The overarching thesis behind all this is the human fat switch.

The final chapters of The Fat Switch address some of the counter arguments to fructose and uric acid as the key to the epidemic of obesity. But there are others. In the first place we have not halted the slope of the still rising incidence of overweight and obesity despite eating and drinking much less sugar including fructose on a population level. The Fat Switch book is 8 years old now. It is not that hard to lower uric acid in the system with safe drugs we have had for a long time. He says that the fat switch works mostly in people who already have obesity and type 2 diabetes and that it must also be accompanied simultaneously by a high fat diet to cause troubles. However there may be more to this story soon. Dr Johnson is working with Pfizer to develop something that might be the magic bullet/another weight loss brake part of a cure for obesity.

At one point in the podcast Dr. Johnson quips that the stupidest nephron is smarter that 10 of the smartest nephrologists. The nephrons are the functional units of the kidney that filter the blood and then absorb all the good stuff back into the blood while rejecting the waste stuff into the urine. By “smart” he means that nephrons can adapt and accommodate and work around any stress that is put on them. I think that you could generalize this idea by saying that even the stupidest frontal lobectomized human body is smarter than any number of the smartest fat scientists.

In the closing sentences of The Fat Switch Dr Johnson waxes philosophical. “ a species we have flipped heads for many times in a row, at a statistical chance that might seem impossible…you could make a case that evolutionary theory either supports or refutes religion and the existence of a higher being. We are fortunate to be here, but it is critical as we move forward that we not only better understand our place in nature, but nature’s place with us.”


#87 – Rick Johnson, M.D.: Fructose—The common link in high blood pressure, insulin resistance, T2D, & obesity? “Fructose turns out to be used by animals as a mechanism to store fat.”

2. Richard J. Johnson MD. The Fat Switch. 2012 by Richard J. Johnson. Printed by

By John DiTraglia

John DiTraglia M.D. is a Pediatrician in Portsmouth. He can be reached by e-mail- [email protected] or phone-354-6605.

John DiTraglia M.D. is a Pediatrician in Portsmouth. He can be reached by e-mail- [email protected] or phone-354-6605.