Presentation on theme: "Sugar, addiction and obesity"— Presentation transcript:
1 Sugar, addiction and obesity Simon ThornleyPublic Health Physician/ PTF/ PhD studentUniversity of Auckland
2 Summary What is science? Is there an obesity epidemic? A brief history of nutritionI get involved…Food addictionWhat next?
3 Dairy photoThis is a sugar palace, no sorry, it’s a dairy. Hard not to find anything not containing sugar. Even the cigarettes behind the counter are over 10% sugar.
4 Museum photo…This is what a grocery shop looked like at the turn of the century – hard to see any food at all, let alone sugar.
5 What is science? “In God we trust, all others must bring data” William Edwards Deming“First establish the facts, then seek to explain them” AristotleAnarchisticConsensus not usefulHypothesis and argumentDisproving useful, not proof.Probabilities over absolutes
6 The obesity epidemic Where has it occurred? Over what time period? Explanations?What have we been told to eat?Is it working?
7 Is there an obesity epidemic? Explain source of data. Definition of obesity. Prevalence on Y axis, years on x- axis. Ask audience for patterns. What do you notice about English speaking countries? Are there any Asian countries? What has happened to the prevalence of obesity in these countries?
8 What happened in the 1960s? Diet-Heart Hypothesis Heart disease caused by saturated fatResponse: 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.
9 Laws of thermodynamics A – B = CA = Energy in (food)B = Energy out (burned, exercise/basal metabolic rate)C = Energy stored (as fat)δA - environmental change (Coke ads/vending machines)
11 My thoughts on obesity 1994 2005 2007 2011 Medical training Traditional Nutritional theory- Energy densityPublic HealthUnderstanding addictionResearchSimilarities between obesity and smokingResearchCritique of energy densityFocus on sugar1994200520072011
18 Carbohydrate?Important, because in a prominent publication summarising findings, not one mention of the health effects of fructose was mentioned.
19 Eating and addiction?“Atkins Diet”An executive who had tried obesity surgery, laxatives, diets, everything…“Often I would shake until I could put some sugar in my mouth”Smoker’s are addicted because they need nicotine to relieve unpleasant withdrawal symptoms. The cigarette provides rapid relief but also keeps them hooked. Sugar is not so commonly associated with physiological withdrawal or addiction but these quotes provide some insight.
20 “I had an hour’s drive from my office to my home, and I knew every restaurant, every candy machine and every soft drink dispenser along the whole route.”
21 What about glucose? Glycemic index very similar for glucose Is carbohydrate the same as nicotine?Is low GI a way out like nicotine patch or gum?
23 Glucose: glycemic index? High GI food such as white bread causes a rapid spike in blood sugar whereas low GI food such as Vogel’s 12 grain, gives a much slower release of glucose. This may predict the addictive potential of food just as the nicotine curve predicts the addictive potential of tobacco delivery devices.
29 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. TruswellDiseases of overnourished societies and the need for dietary change: in the Oxford Textbook of Medicine, 4th Edition.
30 Sugar – traditional views 30% increase over last 30 yearsPopkin BM, Nielsen SJ. The sweetening of the world's diet. Obesity Research 2003;11(11):“empty calorie”Nestle M. Soft drink "pouring rights": marketing empty calories to children. Public Health Reports 2000;115(4):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 mentionedHow much sugar do you think Nzers eat on average?
31 Average NZ consumption: UN statistics (‘07)– 153g/day= 38 teaspoons/ day17% of total energyCompare – 1961 – 33 teaspoons/day
34 Recent guidelines American Heart Association 2002 Circulation 2002;106;“No definitive evidence... Rely on professional judgement”“Consuming fructose either free or in the form of sucrose has neither beneficial or adverse effects”Sitting on the fence
37 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;Why the about face????
38 UpdateUpper limit set to reduce heart disease risk and maintain healthy weight“6 teaspoons per day” for women“9 teaspoons per day” for men
39 Health effects? 1990s ADA encouraged diabetics to eat sugar/HFCS 2000s about face due to ↑triglyceridesSmall 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, (1): pSegal, 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, (7): p
40 Sugar - What has changed? GI ignores fructose –Sugar half fructose (half glucose)4x as sweet as glucoseLinks to gout, diabetesHuman studies limited,Does not trigger satiety hormones→↑hungerE.g. Insulin, CCKJohnson, R.J., et al., Hypothesis: Could Excessive Fructose Intake and Uric Acid Cause Type 2 Diabetes? Endocr Rev, (1): pSegal, 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, (7): p
41 Refined carbohydrate (high GI) Reduced risk of chronic diseaseHeart 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;87:627-37Modest 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.: CD DOI: / CD pub2(3).
42 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.
45 Food addiction-evidence Neural pathways (dopamine)Correlation between obesity & receptor density like other addictionsAutomaticity – serving size, availabilityRise in sugar consumption worldwide over last 40 years.Rodents – sugar induces withdrawal; fat does not.What evidence do we have? I speculate first about the biological plausibility. Volkow has noticed correlations of receptor density to obesity in patients similar to that observed in other disorders. Ample evidence shows that eating behaviour is automatic. Environmental stimuli such as serving size and ease of access are strong predictors of eating behaviour.
46 Dairy photoThis is a sugar palace, no sorry, it’s a dairy. Hard not to find anything not containing sugar. Even the cigarettes behind the counter are over 10% sugar.
48 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.”
49 “I don't 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.”
50 “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. “
51 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
52 Critique: Academia“Any addictive type of hypothesis can't explain the rise that we've seen over the last 20 to 30 years of obesity.Prof. Boyd Swinburn, Professor of Population Health, Deakin University (now U of A) 13 Jan 2009
53 Citique: Academia and Industry “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
58 Conclusions Nutrition ignores hunger, instead focuses on energy Low energy or low fat idea unhelpful for populationsSugar intake continues to riseLikely subtle addiction to refined carb and sugarWe need more research, but if this idea proves true, a change of focus may be necessary, shifting away from fat to sugar
59 Conclusions ↓ sugar likely to ↓ No downsides except $$$ Heart disease ObesityDiabetesDental cariesOther diseases?No downsides except $$$
60 What about children?Marketing sugary foods common
65 Other readingFreedman “Wrong: Why experts keep failing us and how to know when not to trust them”. Little, Brown and Company, (journalist)Taubes G. The Diet Delusion. New York: Vermilion; (physicist/writer)Gillespie D. Sweet poison. Sydney: Penguin; 2008 (lawyer)