What is science? “In God we trust, all others bring data” “First establish the facts, then seek to explain them” Aristotle Anarchistic Consensus not useful Hypothesis and argument Disproof useful, not proof. Probabilities over absolutes
The obesity epidemic Where has it occurred? Over what time period? Explanations? What have we been told to eat? Is it working?
What happened in the 1960s? Diet-Heart Hypothesis Heart disease caused by saturated fat Response: reduce fat (↑sugar or carb.) Cheap sugar (HFCS) American Heart Assoc.– spread to other English speaking countriesTaubes G. The Diet Delusion. New York: Vermilion; 2007.
Laws of thermodynamics A–B=C A = Energy in (food) B = Energy out (burned, exercise/basal metabolic rate) C = Energy stored (as fat) δA - environmental change (Coke ads/vending machines)
My thoughts on obesityMedical training Public Health Research ResearchTraditional Understanding Similarities Critique ofNutritional theory addiction between energy density- Energy density obesity and Focus on sugar smoking1994 2005 2007 2011
Addiction? Automatic behaviourRational behaviour Automatic Addiction – e.g. Planning, behaviour? Automatic,Picking up children e.g. breathing withdrawal, can‘t after work stop, causes harm e.g. heroine Mid brain/brain Cortex stem
What does the good book say? “It is not yet clear whether any single attribute of the Western way of life is particularly important in increasing the risk of diabetes. Excess sucrose has largely been exonerated as an important dietary factor in the aetiology of type 2 diabetes...” J. I. Mann and A. S. Truswell Diseases of overnourished societies and the need for dietary change: in the Oxford Textbook of Medicine, 4th Edition.
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. Sucrose and other free sugars restricted to up to <15% of total caloric intake, due to excess energy and dental caries.Food and nutrition guidelines (Ministry of Health) 2003. Fructose not mentioned
Average NZ consumption: UN statistics (‗07)– 153g/day= 38 teaspoons/ day 17% of total energy Compare – 1961 – 33 teaspoons/day
Recent guidelines American Heart Association 2002Circulation 2002;106;523-527 “No definitive evidence... Rely on professional judgement” “Consuming fructose either free or in the form of sucrose has neither beneficial or adverse effects”
Update... “Originally proposed as the ideal sweetener for people with diabetes... Fructose... has been indirectly implicated in the epidemics of obesity and type 2 diabetes”Circulation 2009;120;1011-1020
Update Upper limit set to reduce heart disease risk and maintain healthy weight “6 teaspoons per day” for women “9 teaspoons per day” for men
Health effects? 1990s ADA encouraged diabetics to eat sugar/HFCS 2000s about face due to ↑triglycerides Small RCTs: Rots teeth; raises triglycerides, ↓HDL, ↑BP, ↑urate.Johnson, 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.
Sugar - What has changed? GI ignores fructose –Sugar half fructose (half glucose) 4x as sweet as glucose Links to gout, diabetes Human studies limited, Does not trigger satiety hormones→↑hunger E.g. Insulin, CCKJohnson, 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.
Refined carbohydrate (high GI) Reduced risk of chronic disease Heart disease, cancer, gallstones. Barclay A, Petocz P, McMillan-Price J, Flood V, Prvan T, Mitchell P, et al. Glycemic index, glycemic load, and chronic disease risk—a metaanalysis of observational studies. Am J Clin Nutr 2008;87:627-37 Modest weight lossThomas D, Elliott E, Baur L. Low glycaemic index or low glycaemic load diets for overweight and obesity. Cochrane Database of Systematic Reviews 2007;Art. No.: CD005105. DOI: 10.1002/14651858.CD005105.pub2(3).
What about saturated fat? Meta-analyses now show no link between eating saturated fat and 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.
Sugar addiction? Yes in rats Anecdote in humans
Food addiction-evidence Neural pathways (dopamine) Correlation between obesity & receptor density like other addictions Automaticity – serving size, availability Rise in sugar consumption worldwide over last 40 years. Rodents – sugar induces withdrawal; fat does not.
After the publicity... my inbox... “For the first three weeks I cut all processed sugar and flour from my diet and suffered mood swings with extreme tension and depression, even a sense of hopelessness at times, I had horrible stomach pains, all my joints and muscles throbbed, and I had the shakes constantly.”
“I dont even know how to describe the horrible headaches that went along with all this. People who knew me started thinking I was hiding a drug problem.”
“The worst physical symptoms have been gone for about two weeks now, and the cravings are finally starting to subside… I look at birthday cake today and all I see is myself curled up in the foetal position crying in bed. “
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
Critique: Academia “Any addictive type of hypothesis cant explain the rise that weve seen over the last 20 to 30 years of obesity. Its not that the whole population becoming more of an addictive personality type or whatever. I think there are other factors to explain obesity at a population level.”Prof. Boyd Swinburn, Professor of Population Health, Deakin University 13 Jan 2009
Citique: Academia and Industry “We write in response to Thornley et al’s viewpoint article “The New Zealand sugar (fructose) fountain...” The data quoted on sugar consumption in New Zealand are presented misleadingly and are not correctly referenced to primary sources.” Parnell and colleagues NZMJ 2010
Conclusions Nutrition ignores motivation to eat, instead focuses on energy Low energy or low fat approach has been unhelpful for populations Sugar intake continues to rise Likely subtle addiction to refined carb and sugar
Conclusions↓ sugar likely to ↓ Heart disease Obesity Diabetes Dental caries Other diseases? No downsides except $$$
My advice… Zero sugar (alternatives) Whole grains over white flour (low GI) No low fat food – tends to be high in sugar or refined carbohydrate
Other lessons Ink is a powerful weapon The ideals of science are only that ‗Authorities‘ hold power over junior scientists (jobs, grants) Going alone takes courage History over latest and greatest
The book ―Sickly sweet: sugar, refined carbohydrate, addiction and global obesity‖ Nova To be released in about three months.
Publications Thornley S et al. The New Zealand sugar (fructose) fountain: time to turn the tide? NZMJ 2010. Thornley S et al. Carbohydrate withdrawal: is recognition the first step to recovery? NZMJ 2010 Thornley S et al. Per capita sugar consumption is associated with childhood asthma prevalence. Primary Care Respiratory Journal. 2011. Thornley S et al. The obesity epidemic: is glycemic index the key to unlocking a hidden addiction? Medical Hypotheses. 2008
Other reading Freedman ―Wrong: Why experts keep failing us and how to know when not to trust them‖. Little, Brown and Company, 2010. (journalist) Taubes G. The Diet Delusion. New York: Vermilion; 2007. (physicist/writer) Gillespie D. Sweet poison. Sydney: Penguin; 2008 (lawyer)