Dr. Richard J. Johnson responds to concerns about his book
There’s a lot of new research coming out about the root causes of obesity and disease that it can keep your head spinning round and round for hours trying to absorb it all. And for all the studies that are released, there are just as many new books ready to tout the latest principles and concepts that are discovered by those scientists and researchers looking at the extraordinary findings that are happening. One of these researchers/authors is Dr. Richard J. Johnson.
Dr. Johnson is the author of a new book entitled The Sugar Fix: The High-Fructose Fallout That Is Making You Fat and Sick which puts forth the hypothesis that fructose alone that is what is responsible for obesity and disease in modern society. This seems to run counter to what Gary Taubes wrote in his instant classic Good Calories, Bad Calories which puts the blame for people being fat and sick on insulin which can be raised by ALL carbohydrates, not just fructose. This contradiction in message was the subject of this blog post last month where a reader shared their concerns about who is right–Johnson or Taubes?
Here’s what the reader shared with me in an e-mail:
I just finished reading a new book called The Sugar Fix.
And now I’m REALLY confused. I thought it would be a low-carb message, but it ended up being a low-FRUCTOSE message with the “calorie is a calorie” theory underpinning it. The author Richard Johnson, who is a medical researcher and a kidney transplant doctor (so he should know his stuff), claims that it is only the fructose in our diets that makes us fat and sick.
Following his logic, because sucrose is half fructose and high-fructose corn syrup (HFCS) contains a lot of fructose, all we need to do to be healthy and lose weight is cut out the fructose in our diets. Practically, of course, this means cutting out all drinks sweetened with sugar and HFCS, and cutting down on table sugar, honey, sweet desserts, etc. What really confuses me is that he claims that starch is not a problem.
He says in this book that insulin resistance is caused by FRUCTOSE, not glucose, and that glucose alone causes insulin to spike, but in the absence of fructose, it will not influence insulin resistance in the slightest. So according to this book, if you have your fructose under control (including fruit only in moderation), then you can still enjoy potatoes, pasta and breads because glucose from starch is not a problem.
Now, I’m going through Good Calories Bad Calories for a third time and Gary Taubes argues convincingly that INSULIN is the problem and leads to weight gain and sickness. You see why I’m confused? The author of The Sugar Fix quotes all the studies, is a researcher himself, and now I don’t know WHAT to think.
I’m sure many of you are wondering the same thing about where Dr. Johnson is coming from because it does seem like he is giving starchy carbohydrate sources a free pass while only pointing the finger at fructose which has indeed produced detrimental effects on both weight and health since the 1970s. But is it the SOLE reason people are fat and sick as Dr. Johnson seems to propose. Let’s ask him and find out.
After reading my blog post about my reader’s concern last month, Dr. Johnson e-mailed me his response which included his rebuttal of Taubes’ theory regarding insulin. Read what he has to say for yourself and decide who you believe. I am working on an interview with Dr. Johnson to be conducted in the next month or so and will air on my podcast show later this year. Maybe this will trigger some questions you would like for me to ask him during the interview, so please feel free to send those to me at email@example.com.
Here is what Dr. Johnson wrote in his e-mail to me:
Recently I had the chance to revisit your excellent web site and saw that a reader was confused after reading my book, The Sugar Fix, since I claim that it is excessive fructose intake that is making us fat and sick whereas many other authors have claimed that other carbohydrates such as starches are also bad. Indeed, Gary Taubes (author of Good Calories Bad Calories) was asked to comment, and while he agreed that excessive fructose intake was bad, he felt that starches were also bad as they elevate insulin levels which according to his theory is what is making us fat.
Mr. Taubes was not familiar with much of our work when he published Good Calories Bad Calories, and more of our studies have just been published or are in press. The quick summary is that we now know that many people who will eventually become diabetic or obese develop telltale signs before this happens—this includes a resistance of their tissues to the effects of insulin, a rise in plasma fats (triglycerides), an increase in blood pressure, and subtle evidence for inflammation within the body. Physicians refer to this as “metabolic syndrome” and it is the best predictor of who will become diabetic in the future. Interestingly, there is now overwhelming evidence in both animals and humans that consuming excessive amounts of fructose will cause this syndrome whereas consuming starches will not. We even know the mechanisms by which fructose causes the syndrome, and it involves a rise in uric acid levels. [By the way, beer also raises uric acid levels even though it does not contain fructose, and we believe this is why excessive beer intake can also cause a similar syndrome of obesity].
We have just published a paper in the American Journal of Physiology in which we fed animals fructose or starch for 4 months. At the end of 4 months the animals fed fructose had lost their ability to regulate their dietary intake (that is, they had become resistant to leptin, the hormone involved in satiety). When animals on fructose were switched to a high fat diet, they ate excessive amounts and became fat quickly. In contrast, the animals fed starch could control their intake, ate less food, and gained less weight gain after switching to a high fat diet. Thus one can view fructose as the fire, and high-fat diets and starches as the firewood.
Gary makes the point that obesity is caused not by consuming excessive calories, but rather by an abnormality in fat regulation. However, when one becomes leptin and insulin resistant, one will not be able to regulate one’s dietary intake and will start to increase one’s weight. Clearly a new “set point” has to become established, or one would continue to gain weight until one would “explode” such as the “Mr. Creosote” character in the movie Monty Python’s Meaning of Life. So Gary is right that there is a resetting of the clock—but it is driven by insulin resistance and leptin resistance, which in turn is a direct consequence of fructose intake.
A key misconception is that elevated insulin levels are bad, regardless of the mechanism stimulating the insulin levels. This is the problem I have with Gary’s book, as well as with the general concern over “the glycemic index.” This latter concept is that foods that raise blood glucose (and hence stimulate insulin) are what is driving the obesity epidemic and cardiovascular disease. This would suggest that starches such as white rice , flour and pasta would be the main forces driving the obesity epidemic. Sugar (which contains both glucose and fructose) also has a high glycemic index because of the glucose content, whereas fructose itself has a low glycemic index and hence might be considered safe (according to this reasoning).
However, the stimulation of insulin is a normal body response and by itself does not cause obesity. Insulin levels rise and fall every time we eat. As mentioned, the feeding of starch to animals does not cause obesity or diabetes. Rather, it is the development of insulin resistance that is the culprit, and consuming too much fructose is one of the best ways to do this. It is not a surprise that bears like to eat honey to increase their fat stores prior to hibernation. The reason some studies show a relation of high glycemic index with obesity is because sugar has a high glycemic index, but it is the fructose content that is the culprit and not the glucose.
So please inform your reader that one of the key protective measures to prevent obesity is to keep one’s fructose intake to approximately one-third of the current American diet. Eating two or three servings of fruit a day is healthy; but eating excessive sugar or foods with large amounts of high fructose corn syrup is not. And do not forget to exercise. Moderation is the key.
I want to congratulate you on your web site and your crusade against unhealthy foods.
With kind regards,
Richard J. Johnson MD
Professor and Chief
Division of Renal Diseases and Hypertension
University of Colorado Denver
Comments or questions anyone? Please share your thoughts in the comments section below.