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Thursday, February 4, 2016

Sugar tax : some hard questions

A sugar tax, or more correctly, a soda tax, is the talk of the town and the darling of the media these days. Far be it for me to spoil the party, but I’d like to ask some questions of the proponents of a soda tax to try and get the full picture and not just the sloganistic headlines.

#1. Given the extensive data that we have to hand on national patterns of food and nutrient intake, all of which can be readily linked to bodyweight or body mass index (BMI), where can I find the relevant report that shows that, of all the foods that might be taxed to curb obesity, soda is the clear target?

The simple answer is that in the myopic propaganda on soda tax, no such extensive analysis exists that I know of. So, we are not taxing savoury snacks, fast foods, sugar or chocolate confectionery or booze. Just soda. And we are doing so simply because it is now a global fashion. Of the foods just mentioned, how do policy makers know their average contribution to energy intake, the % of the population who consume them and the intake of these foods among consumers only? How do policy makers compare econometric models for the application of a tax on such foods? The answer to both questions is that such data has not been gathered and therefore is beyond policy makers. They must just trust the soda tax lobby.

#2. Does a soda tax have universal or limited benefit?

The answer is that only those who consume sugar-sweetened beverages feel any putative impact of a soda tax.  In Ireland, that means that 60% of the population might benefit. So 40% of the Irish adult population is unaffected. Nobody on the planet can possibly argue that obesity resides solely among those who consume sugar-sweetened beverages. So the excess weight problem of those who are non- consumers of sugary sodas is ignored. Politicians, please note how many votes you are ignoring in your zeal for soda taxes as presently formulated.



#3. What would be a measure of success of a soda tax?

There are many end points that could be chosen to measure the success of such a tax and in this blogger’s view, policy makers have right to know (a) what would constitute a success and (b) within what time frame. The most likely measure to be proposed is a fall in the purchase of sugary sodas. Since sodas account for a fraction of sugar intake (calculated by my students as 8% of added sugars for the average of Irish consumers) one would not expect to see a dramatic fall in energy intake arising for a soda tax. Moreover, all of the biological evidence at hand suggests that at least some, if not most, of this small drop in energy intake would be compensated for by increased energy intake from some other food sources. Since the purpose of the proposed soda taxes is to combat obesity, do policy makers not have the right to ask the question: “Notwithstanding your excellent data on altered purchase patterns of soda post the tax, could you please give me data on (a) energy intake changes and (b) BMI changes”? The short answer is that such data are not likely to be forthcoming because the focus must be on those who, at the time of the introduction of the tax, were consumers of sugary sodas. There is no point in national average values since not everyone is equally affected by these taxes. As regards time frames, the policy-makers are never told when would be a fair time to ask the hard questions of success or otherwise.

#4. Is there some unwritten and unuttered expectation among the pro-soda tax lobby, that this is just the start and other putative contributors to obesity will soon be targeted as taxable candidates?

One would be naïve not to believe that next we’ll have fast food or sugar and chocolate confectionery etc. as targets for taxation. If that is the case, might it be too much to ask for some honesty here and to re-run all the existing econometric models in which all possible future combinations are included? What combinations would be least regressive? What combinations would have the greatest impact on energy intakes taking all reasonable consumptions into account? What might the economic elasticity of demand look like for various combinations of taxable food categories? In this bloggers view, multiple taxation strategies are just around the corner. This follows logically from the view of the high priests of public health nutrition that the regulatory environment is the way forward, based on prior experience with seat belts in cars, to tobacco, to alcohol and so on. For sure we need a regulatory environment but we also need a bottom up community involvement, one that is well resourced financially, is multi stakeholder driven and which takes a medium to long-term perspective. An example of this is EPODE community projects on obesity (http://epode-international-network.com)

#5. If sugar intakes fall as a result of single or multiple taxes with a sugar focus, what is the likelihood that the % energy from fat will rise and does that not pose a serious question that merits an answer before we go down the avenue of food taxes to tackle obesity?

There is a phenomenon known as the sugar-fat seesaw. It is poo-pooed by the sugar tax lobby as some odd artifact of data analysis or whatever. The hard experimental data say otherwise. If you covertly or otherwise remove sugar calories from the diet, they will be replaced in part or total by fat calories[1]. The energy density of the diet will rise (fat has 2.25 times the calories of sugar on an equal weight basis) and energy intake will increase among the many who are susceptible to such high-energy diets [2],[3].

NOTE: These are just some of the arguments that will appear in my new book, due for release in April: ”Ever seen a fat fox: Human obesity explored”



[1] Markey O et al (2015) Energy compensation following consumption of sugar-reduced products: a randomized controlled trial. Eur J Nutr. 2015 Sep 9. [Epub ahead of print]
[3]  Hall et al (2015) Calorie for Calorie, Dietary Fat Restriction Results in More Body Fat Loss than Carbohydrate Restriction in People with Obesity. Cell Metab. 2015 Sep 1;22(3):427-36


Thursday, December 17, 2015

Traditional Chinese Medicine: Daring or dangerous


Today’s food and medicine industries are losing trust with consumers who regrettably are misled by TV an endless queue of utterly unqualified food and health gurus who promulgate pure unadulterated nonsense as to the shortcomings of modern food and medicine and the wonders of specific foods and traditional medicinal remedies. Let’s start with food remedies. Manuka honey is a honey produced from the pollen of Manuka trees. It is reported to contain an active ingredient MTG (methylglyoxal), which apparently has approved beneficial effects when its highly purified form is used as an adjuvant in skin wound healing[1]. Putting it in your porridge is no good! In fact, the available governmental data is that for every kilo of honey produced from the New Zealand Manuka tree, an amazing 7 kilos is sold worldwide. So when you buy Manuka honey (usually 6-9 times the price of regular honey) there is a 6 in 7 chance you are being conned (a probability of 86%). But of course if you really want to challenge your beliefs in the gurus, can I recommend you read my Hunza blog (July 22nd, 2014) and if you still believe in the wonders of Hunza water[2] you can get a great deal on Amazon[3]: ”Crystal Energy "Hunza Water" Buy 2, Get 1 Free!” Only $87.50 a pair!!

Turning to Traditional Chinese Medicine (TCM), the humorous side evaporates in light of the very disturbing findings on TCM by a consortium of Australian researchers[4]. They examined 26 TCMs using state of the art analytical equipment and their results can be considered in three areas

1.     The GENOMIC analysis: Sophisticated DNA analysis showed that many samples contained traces of animal species such as dog, cat (including Snow Leopard, an endangered species), frog, rodent, viper, and cow. In addition, many banned plant species were detected: Asarum or wild ginger is a source of Aristolochic Acid, a potent carcinogen; Ephedra, notorious for its use in slimming products where it is purported to act through increased cardiac output; Apocynum or Dogbane/Indian hemp which is poisonous with severe effects on the cardiac system.
2.     The DRUG analysis: Many drugs were detected which have no origins in TCM. These include the antibiotic amoxicillin; the anti-clotting agent, warfarin; ephedrine used to treat asthma and hay fever and drugs used to treat anxiety in veterinary practices.
3.     The CHEMICAL analysis: Arsenic, lead and cadmium at levels well in excess of food grade permitted maxima were widely detected. Multiple drug adulterants were also detected. One TCM had 10 times the permitted maximum levels of the poisonous compound arsenic.
Conclusion: Anyone who thinks that the word “traditional” or the accepted centuries old therapeutic use of a product in the absence of proof of purpose constitutes a vote in safety is quite simply naïve. It is precisely because modern food and medicines are so tightly regulated that they are totally safe to use and where necessary, proven to FDA standards to be effective. This paper raises very serious concerns not just about safety but about fraud. The idea that Snow Leopard was detectable in some samples is ecologically horrific. This beautiful species is the IUCN Red List of Threatened Species.

Monday, November 23, 2015

Physical activity and the politics of healthy eating



When the food industry or its trade associations are questioned about the global problem of obesity, they tend to draw heavily on the modern rise in the physical inactivity side of the coin rather than the energy intake side. Since they have a significant vested interest in the latter, that is understandable. But it does lay them open to the criticism that they have precious little interest in the caloric intake side of obesity and simply argue that energy imbalance is largely due to the decline in physical activity in the last half century. Much of this criticism comes from those who brand the food industry in the worst possible light right down to the direct comparison with the tobacco industry and scientists who receive money from the food industry in the study of physical activity are drawn into this scenario. I have previously blogged on this issue so I will just highlight here some of the arguments. Those that belittle or reduce the role of physical activity point out that in the last 50 years, there has in fact been a rise in leisure time physical activity. Now this is true for a proportion of the population but it is be no means universally true and endless national reports document the continued domination of a sedentary lifestyle. They are also likely to cite published papers, which argue that the rise in caloric intake exactly parallels the rise in obesity. They are more likely than not to ignore the compelling data that whereas leisure time physical activity has increased, work related physical activity has plummeted. They are also likely to ignore data on daily physical activity among the traditional Amish community who continue to live a life of high work and leisure-related physical activity, a lifestyle now utterly demolished at work due to the advent of multiple labour-saving devices, from automation to the silicon era. They are also likely to downplay the importance of papers that argue that the rise in obesity does not match the rise in caloric intake when correct adjustments are made for rising food wastage. So lets look again at the issue of physical activity in the management of bodyweight.

Question 1: Is physical inactivity really a serious contributor to ill health? The WHO certainly thinks it is. They write thus: “Physical inactivity (lack of physical activity) has been identified as the fourth leading risk factor for global mortality (6% of deaths globally). Moreover, physical inactivity is estimated to be the main cause for approximately 21–25% of breast and colon cancers, 27% of diabetes and approximately 30% of ischaemic heart disease burden.” Rightly they point out the “exercise” is not the same as “physical activity”: The term "physical activity" should not be mistaken with "exercise". They write: “Exercise, is a subcategory of physical activity that is planned, structured, repetitive, and purposeful in the sense that the improvement or maintenance of one or more components of physical fitness is the objective. Physical activity includes exercise as well as other activities which involve bodily movement and are done as part of playing, working, active transportation, house chores and recreational activities”. In short, exercise implies changing into sports gear. Physical activity you can do in your work clothes.

 Question 2: Is body weight the correct end point to use when considering physical inactivity and health? Physical inactivity is ranked 4th by the WHO as a major contributor the global burden of disease while obesity is ranked just below that as the 5th biggest cause of global mortality. Two of the major adverse effects of obesity are poor cardio-respiratory function and poor blood glucose control and physical activity can greatly reduce these two adverse effects.  So obesity is visible but you can’t eyeball someone to ascertain his or her cardio-respiratory or blood glucose function. Thus, it is far more important to regard the role of physical activity as maintaining optimal heart and blood glucose function than it is to regard enhanced physical activity as a solution to obesity. Nonetheless, the absence of modest levels of physical activity, is, as we will see, a major risk factor for weight gain.

Question3. Is exercise bashing and industry funding really a problem? From time to time, it becomes fashionable to ridicule the role of physical activity. An editorial in the British Journal of Sports Medicine wrote thus: “It is time to wind back the harms caused by the junk food industry’s public relation machinery. Let us bust the myth of physical inactivity and obesity. You cannot outrun a bad a diet”. I Sensationalist rubbish! An important peer-reviewed paper published recently in the leading journal (the American Journal of Clinical Nutrition) that I will now look at, was written by the top US researchers in the field of physical inactivity, health status and obesity. The study was supported by “an unrestricted research grant from the Coca Cola Company” and of course that led to considerable criticism. The fact that it was co-funded by the National Cancer Institute was of course ignored. The University of Colorado Medical School, where one of the leading authors works, recently returned a $1 million Coca Cola grant for physical inactivity research[1]. And of course, the Coke funding was likened to funding of the tobacco industry in the smoking area.

The main feature of the study that these authors published was that it looked at the long-term effects of. The authors go back in time to a very early study of low levels of physical activity in employees in the Ludlow Jute Company in Calcutta[2]. Those with low levels of physical activity included clerks, shopkeepers and supervisors whilst those with high physical activity included blacksmiths, coalmen and bale carriers. The authors of this 60 year old paper introduce their work with the following statement: “It has been stated-or implied-by many workers that the regulation of food intake functions with such flexibility that an increase in energy output due to exercise is automatically followed by an equivalent increase in caloric intake. This view, usually accompanied by a minimization of the energy expenditure due to exercise, has often led to the disparagement of physical activity as a factor in weight control. The fallacies inherent in such an attitude have been discussed.” These authors back in 1956 showed that the following: Body weight was highest among those with the lowest level of physical activity. However, as physical activity increased beyond that point, body weight remained constant. Research techniques have changed dramatically since then and the recent research re-visited this area. 421 subjects were recruited into this 1-year study. Accelerometers were used to repeatedly measure physical activity and subjects were classified into quintiles (fifths) of Moderate to Vigorous Physical Activity (MVPA). Energy intake was assessed by repeated dietary assessment combined with measurements in energy balance. Body fat mass was assessed using sophisticated X-ray technology. The two main findings of the study re-affirm what was shown 60 years ago: (1) above the lowest level of physical activity, there was a positive correlation between rising energy intake and rising physical activity. That was not so at the lowest level of physical activity. (2) The accumulation of fat mass was highest among the least physically active, while across the remaining fifths of physical activity, no changes in fat mass was seen. Both studies point to the dominant role of low levels of physical activity as the problem in body weight regulation. Beyond that lower level of physical activity, additional physical activity had no effect. So sitting as a couch potato has a much more important effect on long-term body weight regulation than pounding the pavement or gym. So what would a couch potato have to do to escape this gloomy fate? The more modern paper [3]can estimate this as steps per day since it measured these. The finding is that just over 7,000 steps per day would get the couch potato out of trouble. That is easily attainable in simple walking programmes of about 30 minutes duration. So to conclude:
  1. Physical inactivity is a global killer, actually ahead of obesity
  2. When we come to look at suitable end points of improved physical activity, improved cardio-respiratory fitness and improved management of body weight are best achieved in getting off the couch. Running marathons won’t yield a pro-rata improvement.
  3. Bashing physical activity and physical activity researchers because of industry funding, is a popular headline grabbing exercise. It particularly helps those who have the view that obesity is caused by large food corporations and who believe that any focus on physical activity detracts from that near criminal activity






[2] Mayer J et al (1956) Relation between Caloric Intake, Body Weight, and Physical Work: Studies in a West Bengal situation. Am J of Clin Nutr: 12,169-175

[3] Shook RP et al (2015) Low levels of physical activity are associated with dysregulation of energy intakes and fat mass gain over 1 year. Am J Clin Nutr e-pub ahead of print

Friday, August 14, 2015

Shed fats, not carbs ~ new human study

In recent years, it has become quite fashionable to argue that the real culprit in obesity are carbohydrates and as such fats have gained considerably good marks in the hierarchy of villainous calories. Gary Taubes, a highly influential author on this topic wrote thus: ‘‘Any diet that succeeds does so because the dieter restricts fattening carbohydrates .Those who lose fat on a diet do so because of what they are not eating—the fattening carbohydrates’’. The argument is that carbohydrates cause a surge in insulin release and insulin is what keeps fat within fat cells. When carbohydrates are restricted, this insulin surge falls allowing fats to be released from fatty tissue for burning (oxidation) for energy. All very well in theory but now, the results of an impeccably designed human study will greatly challenge this recent view that fats are good and barbs are bad[1]. So what makes this study so solid.

The volunteers were extremely obese. The males had a BMI of 38 while that of females was 33. The study randomized the subjects into two arms for 11 days of dietary intervention and all of the period of dietary intervention was conducted in a metabolic ward with strict clinical supervision. For the first 5 days in each study arm, the subjects ate what is referred to as a eucaloric diet. That is, they received the exact amount of calories that they needed simply to neither gain nor lose weight. The nutritional composition of each subjects eucaloric diets was identical with 50% energy from carbohydrate, 35% from fat and 15% from protein. For the next 6 days, their caloric intake was reduced by 30% either through a very low fat diet or a very low carbohydrate diet. There were no other changes in the composition of the calorie reduced diets. The only foods available to the subjects were those prepared by the research team and all eating occasions were supervised.

 On days 2 and 5 of the eucaloric diet and on days 1, 4 and 6 of the energy restricted diets, the subjects spent 23 consecutive hours inside a metabolic chamber. This would be a small room with a bed, seat, bathroom and other facilities but which is specially constructed to measure the inflow and outflow of oxygen and carbon dioxide. By measuring the loss of oxygen (used for fuel) and the gain of expired carbon dioxide, it is possible to accurately tell what type of fuel is being burned by the body for energy.  When the six days of dieting ended, the subjects took a 2-4 week break before resuming the same protocol but switching from the low fat arm to the low carbohydrate arm and vice versa.

The main effects were as follows, as outlined by the authors: “Body fat loss was calculated as the difference between daily fat intake and net fat oxidation measured while residing in a metabolic chamber. Whereas carbohydrate restriction led to sustained increases in fat oxidation and loss of 53 g/day of body fat, fat oxidation was unchanged by fat restriction, leading to 89 g/day of fat loss, and was significantly greater than carbohydrate restriction”.

To those of us in experimental nutrition for some time, these results come as no surprise. Very similar results were found in a series of studies carried out at the UK Dunn Nutritional laboratory in the 1990s. The bottom line is this. If you want to lose fat from the body, first lose it from the plate but make sure that the caloric deficit of fat leads to an overall deficit of calories form the diet.  



[1] Hall K et al (2015) Cell Metabolism, 22, 1-10