A retrospective of the fructose alarmism debate
2010 February 19
After 300 comments and counting, it’s safe to agree with Nigel Kinbrum that my recent critique of Dr. Robert Lustig’s fructose lecture “has caused a bit of a stir in the nutritional blogosphere.” The intense debate (& discussion) that ensued inspired me to re-cap some things I feel were most interesting. There was plenty of learning to be had on both sides of the fence. Here are the highlights as I see them:
- Dr. Lustig showed up, to the excitement and anticipation of all, including me. He went 3 rounds with me, which was actually more than I expected.
- In round one, he defended his position using survey data that was contrary to the ERS/USDA data, which is well and good. I don’t disagree that survey data in general is pretty messy and equivocal, not to mention, incapable of establishing causal relationships. He then repeated his claim that the Japanese diet contains no fructose outside of fruit. Perhaps due to hasty error, he says, “That is what we are talking about here; added dietary sugars; not endogenous ones.” I’m going to assume he meant to say intrinsic sugars, not endogenous sugars. In any case, this idea that the Japanese do not add sugar to their diets is completely false – regardless of which regional or traditional aspect of Japan you’re talking about (this actually was never specified). He also mentioned the revised recommendations of the American Heart Association (AHA), which David Gillespie follows up on towards the end of the discussion, where the full picture is omitted until I post it up (I’ll get to that).
- In my rebuttal to Lustig’s initial comment, I first point out the limitations of epidemiological data, as well as Lustig’s neglect of the numerous factors that have contributed to a reduction in energy expenditure, such as, “an increase in sedentary occupations; an increase in two-income households and single-parent households; transportation and infrastructure changes that discourage physical activity; a decrease in PE classes and extracurricular sports programs in schools; an increase in sedentary forms of entertainment (i.e. TV/movie viewing, video games, internet, etc.); demographic changes (i.e. aging population, immigration, etc.); a decrease in food costs with increase in food availability and changes in food consumption patterns” (study here). I finish off by pointing out the error of the claim regarding the Japanese diet, and mention Lustig’s omission of giving concrete numbers in his lecture regarding the dose-dependent safety of fructose in the diet.
- Lustig’s 2nd round defense was merely a cut/paste of the abstract of a 31 year-old epidemiological study showing that, “a high fat, high simple carbohydrate, low complex carbohydrate diet and/or reduced levels of physical activity increase risk of diabetes.” My rebuttal to this was simple. I pointed out how Lustig was not only using uncontrolled data to support his stance, but he was being selective about what the observational data showed. I used the study he posted plus two more recent studies to show the common thread among each of them: an increase in fat, an increase in sugar, and a decrease in physical activity was associated with adverse health effects. Clearly, it’s incorrect to selectively scapegoat the single factor of your personal choice.
- In Lustig’s final defense, he first cites as study wherein roughly 150 grams of fructose (the equivalent of 6-7 cans of non-diet soda), increased visceral adiposity and reduced insulin sensitivity in overweight & obese subjects. Does this surprise anyone? The study he cited used a fructose dose that’s 3 times the average American intake. He then goes on to cite rodent research despite his acknowledgement of my demand for human interventions using non-stratospheric doses of fructose. All this, after my multiple citations of human research showing the contrary. To top everything off, Lustig cited his Youtube popularity as a basis of accuracy and credibility. That was not a good move. My rebuttal to Lustig’s final comment is right here.
- I emailed Lustig, thanking him for the discussion, and he responded by preaching to me more of his gospel. I politely asked that he take his argument back to the blog since the purpose of the whole discussion in the first place is to educate the public. He would have none of that, quipping that “real scientists” don’t go tit-for-tat on blogs, they go to journal clubs to discuss research with other “real scientists.” If his case was as strong as he thinks it was, he wouldn’t have gotten embarrassed by the opposition.
- As I mentioned in response to a straight-shooting article by Martin Berkhan, Lustig probably has more education and native intelligence than he knows what to do with. However, as he demonstrated, you can be the most brilliant guy in the world & still find yourself fumbling over groundless claims.
- Comments by Ryan Zielonka (here), RG (here), DSD (here), and Rob (here) illustrate the regional heterogeneity of the Japanese diet, and how it can’t be simply pegged as fructose-free aside from the fruit intake.
- Fred Hahn brought his classic carbophobic flair (here), which was well-rebutted by Mike Howard (here) and Leigh Peele (here).
- Ganine asked the question of whether or not HFCS has different metabolic effects than regular sugar (sucrose). James Krieger came in with a follow-up response stating that, “The only practical difference between sucrose and HFCS is in the bonding. The glucose & fructose in HFCS is mainly free and unbonded, while it is bonded in sucrose. However, this makes no *meaningful* difference in regards to metabolism in the body. The bonds in sucrose are quickly broken when sucrose hits the acid environment of the stomach. This means that once sucrose hits the stomach, it’s no different from HFCS. Once you get to the small intestine, metabolism is *exactly* the same. This *little bit of difference* does not lead to the problems Dr. Lustig talks about. The fact is, HFCS and sucrose are identical as far as your body is concerned. The difference in bonding wouldn’t make a shred of difference in regards to your health.”
- Speaking of James Krieger, I’d like to direct anyone interested in fructose metabolism to this fine tutorial here.
- In response to Mike K’s advocacy of food avoidance, I posted research indicating an association between inflexible, all-or-nothing eating habits and adverse conditions. To quote Stewart et al, “The study found that individuals who engage in rigid dieting strategies reported symptoms of an eating disorder, mood disturbances, and excessive concern with body size/shape. In contrast, flexible dieting strategies were not highly associated with BMI, eating disorder symptoms, mood disturbances, or concerns with body size.”
- Here’s a quote from a similar study by Smith et al: “Subjects were administered questionnaires measuring dietary restraint, overeating, depression and anxiety. Measurements of height and weight were also obtained in order to calculate BMI. Canonical correlation was performed to evaluate the relationship of dietary restraint variables with overeating variables, body mass, depression and anxiety. The strongest canonical correlation (r=0.65) was the relationship between flexible dieting and the absence of overeating, lower body mass and lower levels of depression and anxiety.”
- Indeed, correlation doesn’t automatically equal causation, but the two studies I cited above build a far better case than the baseless assumptions of folks who assert their dietary perfectionism onto the world around them.
- Ardent sugarphobe David Gillespie presented some very engaging arguments. However, he ignored all other posters, as well as the evidence I presented. He correctly pointed out that John White’s HFCS article contained a citation of research that did not support the point he was making (good catch, David!). However, he went on to dismiss reams of data on the grounds of funding source. He also incorrectly accused a study of being funded by the Coca Cola company, when in fact, Coke funded the travel expenses after the study was already complete. As James pointed out, the study was funded by a scholarship, two fellowships, and a grant from the Canadian government. Beyond that, studies should not be judged solely on funding source; the weight of their scrutiny should rest on their quality of design.
- David responded by citing the AHA’s recommendations, which I’ll quote him as saying, “Of particular note is their final recommendation that an adult male should consume no more than 144 calories (38 g) per day in added sugars (which would be 19g of fructose).” The problem with this is that it omits the range of doses the AHA listed for various populations, which went as high as 19 teaspoons of sugar per day for active males, which is double the figure that David emphasized. Of course, it’s convenient to leave out the higher end when you’re building a case that’s biased toward sugar avoidance. Go here to see my response to this, which includes a screen shot of the chart in the AHA paper.
- In my final rebuttal to David, I explain what discretionary calories are, and how their intended use further supports the point I made in my original article. To quote my response, “The discretionary allotment for an active male is 512 kcal, and a sedentary one is 290 kcal. The average of this is 401 kcal. Technically, it wouldn’t violate the AHA’s recommendations if someone’s entire discretionary kcals came from sugar, which in the case of 401 kcals is about 100g, which equates to 50g fructose, which brings us right back to the exact number I listed as the upper safe limit in my original article.”
- An honorable mention is deserved for the most epic comment, by Jamie Hale.
http://www.ncbi.nlm.nih.gov/pubmed/19592634
http://www.ncbi.nlm.nih.gov/pubmed/18996880
http://www.ncbi.nlm.nih.gov/pubmed/20047139
http://www.ncbi.nlm.nih.gov/pubmed/20086073
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2991323/
