Sunday, May 24, 2015

Sugar Intake or Food Quality - What's the True Motor of the Obesity Epidemic? Plus: What's New in Sports Nutrition?

People don't eat too much sugar. They simply make the wrong food choices.
With the publication of the latest issue of the Nutrition Bulletin from the British Nutrition Foundation, I am facing a whole host of potentially news-worthy recent papers. Of actual significant interest are yet only two of them. One that focuses on the involvement of different sugars in the obesity epidemic and a second paper that's actually a summary of an expert meeting discussing "what's new in sports nutrition". I have to admit, though, "new" is a relative term - specifically if you are not just reading each and every SuppVersity article, but also all the SuppVersity Facebook News, these "news" shouldn't be that "new" for you.
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  • Sugars and obesity: Is it the sugars or the calories? - In this article Choo et al. (2015) discuss the emerging evidence pointing towards sugars containing fructose as potential motors of the obesity epidemic.

    As the reviewers point out, the hypothesis that fructose may be at the heart of the obesity epidemic "is largely supported by ecological observations, rodent models of overfeeding and select human trials" (Choo et al.). This does also imply that...
    "[h]igher level evidence from systematic reviews and meta-analyses of controlled dietary trials has yet to show convincingly that fructose-containing sugars behave differently from any other forms of energy (especially refined starch and fat)" (Choo. 2015).
    Prospective cohort studies, which provide the strongest observational evidence, have shown an association between risk of overweight and obesity and fructose-containing sugars consumed as sugar-sweetened beverages but not as total sugars or other important sources of added sugars such as cakes, pastries and sweets. I mean, it's no coincidence that potato chips and French fries, not 100% fruit juices have been identified as the driving motors of the belly development in the the Nurses’Health Study, the Nurses’ Health Study II and the Health Professionals Study from the US (see Figure 1 | Choo. 2015).

    Figure 1: Bodyweight changes (kg) over a 4-year period associated withan increase in the consumption of different food items in the Nurses’Health Study, the Nurses’ Health Study II and the Health Professionals Study from the US (Choo. 2015).
    Comparative analyses show that high intakes of other highly palatable foods such as refined grains, processed meats, red meats, French fries and potato products, as well as physical inactivity may play an equal or greater role in weight gain and the risk of overweight and obesity. The contributions of these factors are also difficult to disentangle from that of sugar-sweetened beverages owing to their collinearity with sugar-sweetened beverages as part of a Western dietary pattern and lifestyle.

    Therfore, the scientists demand that "[a]ttention needs to remain focused on decreasing overconsumption of all foods associated with overweight and obesity." In that, they admit that "[s]ugar-sweetened beverages and foods are certainly an important place to start," but also highlight that one "should not draw attention away from the issue of overconsumption in general" (Choo. 2015).
  • What's new in sports nutrition? The  British Nutrition Foundation's half-day symposium ‘What's new in sports nutrition?’ brought together world-leading sports nutrition experts to discuss the latest and most significant findings in sports nutrition.

    Discussion centred on injury and illness prevention, training adaptation and competition performance, with particular focus on the role of nutrition in bone health, immunity, skeletal muscle changes and the interplay of sports nutrition with sleep. Dr Kevin Currell chaired proceedings. For the former, i.e. the prevention of inury and illness, the most interesting study was one in male gymnasts. A study that used a 2g/kg bodyweight protein + low GI carbohydrate + high fiber diet wit 400ml of milk and creatine supplementation to effectively reduce the body weight and thus the load on the joints and prevent injury in male gymnast who frequently experienced injury post competition.
    Figure 2: Muscle mass and body fat in response to 6 weeks high protein, high fiber, low GI carb diet in male gymnasts with who frequently experienced injury post competition (unpublished data according to Alerton. 2015).
    In fact, the gymnast lost 5 kg over the 6-week period (from 71 to 66 kg), percentage body fat fell by 8% (from 17% to 9%) and lean body mass stayed relatively similar (56.6–57.1%). Most intriguingly, the change in bodyweight led to reduced injury and increased training capacity.

    The researchers who had been invited to the conference also presented evidence in favor of the gut and immune protective prowess of colostrum, which has
    Figure 3: Colostrum supplementation has been shown to blunt the exercise induced reduction in endogenous anti-oxidants and potentiates its beneficial effects (Appukutty. 2012 | learn more)
    "[...] considerable evidence to suggest that [...] supplementation can maintain immunity and decrease the risk of URTIs [upper respiratory tract infections], particularly during periods of heavy training. Supplementation can also limit exercise-induced increases in gut permeability, which in turn may confer benefits on immune function and reduce GI complaints. 
    However, beneficial effects of colostrum are less pronounced following acute intake; longer term supplementation (>2 weeks) is required for maximal effects. Moreover, many previous studies have used high doses of bovine colostrum (10–60 g/day) and further work is needed to establish dose–response effects and optimal dosing" (Alderton. 2015).
    That's not exactly news, just like the importance of sleep for optimal athletic performance or the beneficial of glycogen depletion on mitochondrial adaptation to exercise I discussed back in back in 2012, already.
The processing of foods and our preference for processed junk is also behind the "Prevalent Nutrient Deficiencies in the US" I wrote about in detail in a previous SuppVersity article from January of this this year. Deficiencies in vitamins, minerals, fiber and much more | learn more.
What else is of interest? Well, I guess this would be the editorial by Dr Hilary Green who discusses dietary carbohydrates from a"food processing perspective". In her article, she contrasts the "significant advantages for human evolution" that came with the invention of food (and carbohydrate) processing techniques and the modern backlash that comes with (over-)processed foods and a processing-related nutrient loss.

Based on her assessment of the current state of the art food processing, fortification, consumption and production trends, Green demands to "look at nutrition through two lenses – one that focuses on access to good nutrition for the current generation and the other that addresses the fact that we have to do this in a way that will not compromise future generations" (Green. 2015) | Comment on Facebook!
  • Alderton, S. and Chambers, L. (2015), What's new in sports nutrition?. Nutrition Bulletin, 40: 140–148. doi: 10.1111/nbu.12144
  • Choo, V. L., Ha, V. and Sievenpiper, J. L. (2015), Sugars and obesity: Is it the sugars or the calories?. Nutrition Bulletin, 40: 88–96. doi: 10.1111/nbu.12137
  • Green, H. (2015), Dietary carbohydrates: A food processing perspective. Nutrition Bulletin, 40: 77–82. doi: 10.1111/nbu.12135