'Low carb downunder' conference


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These are the slides I presented at the 'low carb downunder' conference in Sydney on the 24th of November 2012.

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  • Eg. vitamin D. Plausible biological mechanism, consistent studies.Essentially inductionist principles. Critique: Rely heavily on the subjective judgement of the reviewer. Temporality particularly important (prospective studies stronger). Expanding scientific literature makes almost all plausible hypotheses supported.
  • Important, because in a prominent publication summarising findings, not one mention of the health effects of fructose was mentioned.
  • How much sugar do you think Nzers eat on average?
  • Why the about face????
  • 'Low carb downunder' conference

    1. 1. Has nutrition research helped us with our food choices? Simon Thornley (Epidemiologist) University of Auckland
    2. 2. Summary What is science/epidemiology? A brief history of human nutrition I get involved… diversion into tobacco Food addiction? What next?
    3. 3. My view Yes, but many nutrition scientists are not listening to the data Fructose, sugar, carbohydrates are often overlooked
    4. 4. What is science or research? “In God we trust, all others bring data”  William Edward Deming “First establish the facts, then seek to explain them”  Aristotle
    5. 5. Science Anarchistic; consensus not useful Hypothesis and argument Disproof over proof Uncertainty over absolutes Integration
    6. 6. A basic epidemiological study… Disease Subjects What we eat Focus on statistical over biological evidence…
    7. 7. Error… Many contradictory studiesNot included in CI or p-value Accounted for by 95%[Quantitative bias analysis] Error confidence interval and p-value Selection bias recruitment %Information Systematic Random biasAccuracy of measures? Unmeasured False +ve False –ve ~5% ~10 to 20% confoundingRCT? From literature?
    8. 8. Confounding… Sugar consumption Coronary Heart Dental caries Disease
    9. 9. Bradford-Hill Criteria Strong  RCT better than association? observational study Consistent?  Makes sense Does cause come before effect? More exposuremore disease?
    10. 10. Salt restriction Salt restriction ↓ blood pressure Observational studies show both ↑ and ↓ survival (unmeasured confounding) Only randomised study shows benefit in group that didn’t restrict salt. Taylor, R. S., Ashton K. E., T. Moxham, L Hooper, and S. Ebrahim. "Reduced Dietary Salt for the Prevention of Cardiovascular Disease." Cochrane Database of Systematic Reviews, no. 7 (2011). http://www.mrw.interscience.wiley.com/cochrane/clsysrev/articles/CD009217/frame.html .
    11. 11. Is the idea falsifiable?HOW DOES SCIENCE GOWRONG?
    12. 12. How it works in theory… Idea Experiment Interpret New Idea Generate Test Inferences from Refinehypothesis hypothesis experiment hypothesis
    13. 13. In reality…? Experiment Interpret New Idea Generate Test Inferences from Ideahypothesis hypothesis experiment Refine hypothesis
    14. 14. Some history…NUTRITION IDEAS OVER THELAST 100 YEARS…
    15. 15.  Museum photo…
    16. 16.  Dairy photo
    17. 17. What happened in the 1960s? Diet-heart hypothesis Heart disease caused by saturated fat Response: reduce fat (↑sugar or carb.) Cheap sugar (HFCS in USA) American Heart Assoc  other English speaking countriesTaubes G. The Diet Delusion. New York: Vermilion; 2007.
    18. 18. Brain washing?THE ACCEPTED STORY
    19. 19. Nutrition to the rescue… A–B=CA = Energy in (food)B = Energy out (burned, metabolism)C = Energy stored (as fat)Cause↑A/↓B→↑C – obesigenic environment (↑energyin/ reduced energy out)
    20. 20. What’s ok...THE GOOD!
    21. 21. It’s not OK... Ever!THE BAD
    22. 22. http://longwhitekid.files.wordpress.com/2011/08/anchor-best-new-zealand-butter-380h-x-270w-heavy-card-21.jpg
    23. 23. Salt
    26. 26. My thoughts on obesity…Medical training Public Health Research ResearchTraditional Tobacco Similarities Critique ofNutritional theory addiction between energy density- Energy density obesity and Focus on sugar smoking1994 2005 2007 2011
    27. 27. Why does a smoker smoke?
    28. 28. Withdrawal Symptoms Duration (weeks) Irritability <4 Depression <4 Restlessness <4 Poor concentration <2 Increased appetite >10 Craving to smoke >2
    29. 29. Automatic behaviour Rational Automatic Addiction breathing Automatic, behaviour withdrawal, harm Mid brain/brain Cortex stem
    30. 30. Subconscious learning… Withdrawal discomfort Puff cigarette Nicotine metabolised Withdrawal More relief puffs
    31. 31. How do cigarettes work...?
    32. 32. FOOD ADDICTION?
    33. 33. Carbohydrate?
    34. 34. Eating and addiction? Atkins Diet An executive who had tried obesity surgery, laxatives, diets, everything…“Often I would shake until I could putsome sugar in my mouth”
    35. 35.  “Ihad an hour’s drive from my office to my home, and I knew every restaurant, candy machine and soft drink dispenser”
    36. 36. What about glucose? Is refined starch the same as nicotine? Are low GI foods the obese person’s equivalent to a smoker’s nicotine patch or gum?
    37. 37. Bread: white v. wholegrain
    38. 38. Glucose: glycemic index?
    39. 39. What about sugar? Sugar is actually low/moderate GI
    40. 40. I TAKE A LOOK AT SUGAR?
    41. 41. The medical gurus say sugar isOK? “Excess sucrose has largely been exonerated as an important dietary factor in the aetiology of type-2 diabetes...”J. I. Mann and A. S. TruswellDiseases of overnourished societies and the need for dietary change: in theOxford Textbook of Medicine, 4th Edition. Postprandial glycemia (GI) used to exonnerate sugar…
    42. 42. Sugar: traditional views 30% increase over last 30 yearsPopkin BM, Nielsen SJ. The sweetening of the worlds diet. Obesity Research 2003;11(11):1325-32. “Empty calorie”Nestle M. Soft drink "pouring rights": marketing empty calories to children. Public Health Reports 2000;115(4):308-19. Fructose not mentioned Something is missing?
    43. 43. Update... AHA turns around. “Fructose... has been indirectly implicated in the epidemics of obesity and type 2 diabetes”Circulation 2009;120;1011-1020
    44. 44. Fructose: what has changed? GI ignores fructose Sweeter than glucose Linked to:  Gout, diabetes, weight gain, metabolic syndrome  Hypertension, rotten teeth  High triglycerides, dyslipidaemia, CVD Tends to ↑ hungerJohnson, R.J., et al., Hypothesis: Could Excessive Fructose Intake and Uric Acid Cause Type 2 Diabetes? Endocr Rev, 2009. 30(1): p. 96- 116.Segal, M.S., E. Gollub, and R.J. Johnson, Is the fructose index more relevant with regards to cardiovascular disease than the glycemic index? European Journal of Nutrition, 2007. 46(7): p. 406-17.
    45. 45. What about saturated fat? Recent summaries  no association with heart disease.Skeaff CM, Miller J. Dietary Fat and Coronary Heart Disease: Summary of Evidence from Prospective Cohort and Randomised Controlled Trials. Ann Nutr Metab 2009;55:173–201Mente A, de Koning L, Shannon HS, Anand SS (April 2009). A systematic review of the evidence supporting a causal link between dietary factors and coronary heart disease. Arch. Intern. Med. 169 (7): 659–69.
    46. 46. Food addiction: evidence Addiction pathways Eating is automatic Rats  sugar induces withdrawal; not fat.
    47. 47. In the headlines…
    48. 48. My inbox... “For three weeks I cut all sugar and flour… then…  mood swings…,  depression…,  stomach pain…,  joint and muscle pain…,  the shakes….”
    49. 49. “People who knew me started thinking I washiding a drug problem.”
    50. 50. Overeater’s Anonymous “When you are addicted to drugs you put the tiger in the cage to recover; When you are addicted to food, you put the tiger in the cage, but take it out three times for a walk” Kerri-Lynn Murphy Kriz
    51. 51. Critique: Academia “Any addictive … hypothesis cant explain the rise that weve seen over the last … 30 years of obesity.”Prof. Boyd Swinburn, Professor of Population Health, Deakin University 13 Jan 2009
    52. 52. SO WHAT?
    53. 53. Synopsis Nutrition focuses on energy not hunger Low fat idea predates obesity epidemic Sugar intake continues to ↑ Likely subtle addiction Likely cause of major risk factors for heart disease Many nutrition researchers stuck in energy paradigm (cf. some pop science)
    54. 54. More details
    55. 55. Thank you!Slides and my articles areavailable at:www.slideshare.net/sithor