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Why Study Energy Balance and How? Office of Energetic s.

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Presentation on theme: "Why Study Energy Balance and How? Office of Energetic s."— Presentation transcript:

1 Why Study Energy Balance and How? Office of Energetic s

2 Disclosure I have received financial and other benefits from the following entities: the Frontiers Foundation; The Federal Trade Commission; Vivus, Inc; Kraft Foods; University of Wisconsin; University of Arizona; Paul, Weiss, Wharton & Garrison LLP; Sage Publications, and additional government, non-profit and for- profit organizations with interests in obesity, nutrition, and health.

3 Outline 1.Why do we even need to study EB? 2.Key Scientific Question. 3.Study duration/time-frame. 4.Selecting the endpoints. 5.Concerns about measurement error. 6.The value of quasi- and natural-experiments. 7.The possibility of true randomization should not be underestimated.

4 Diana Thomas’ Software

5 If we controlled all the obvious factors, we would control weight to within trivial differences, right? Miller RA, Harrison DE, Astle CM, Floyd RA, Flurkey K, Hensley KL, Javors MA, Leeuwenburgh C, Nelson JF, Ongini E, Nadon NL, Warner HR, Strong R. An Aging Interventions Testing Program: study design and interim report. Aging Cell. 2007 Aug;6(4):565-75. Epub 2007 Jun 18.

6 What if we all just ate a little bit less? Mild calorie restriction induces fat accumulation in female C57BL/6J mice.Mild calorie restriction induces fat accumulation in female C57BL/6J mice. Li X, Cope MB, Johnson MS, Smith DL Jr, Nagy TR. Obesity (Silver Spring). 2010 Mar;18(3):456-62.

7 What if we all just ate a lot less? [40% DR] Liao CY, Rikke BA, Johnson TE, Gelfond JA, Diaz V, Nelson JF. Fat maintenance is a predictor of the murine lifespan response to dietary restriction. Aging Cell. 2011 Aug;10(4):629-39.

8 How about Primates? A rapidly occurring compensatory decrease in physical activity counteracts diet-induced weight loss in female monkeys. “18 adult ovariectomized female monkeys were placed on a low-fat diet, and available calories were reduced by 30% compared with baseline consumption for 1 mo. Surprisingly, there was not significant weight loss.” Am J Physiol Regul Integr Comp Physiol. 2010, Apr; 298(4):R1068-74.

9 How about Great Apes (Homo Sapiens)?

10 Mandatory food supplementati on studies: Preliminary unpublished data.

11 Based on CSFII data. Energy Compensation Within a Day Anderson, Michael and David A Matsa. 2011. Are Restaurants Really Supersizing America?. American Economic Journal: Applied Economics. 3(1): 152-188.

12 Compensation is Sometimes Cognitively Mediated C. Werle, B. Wansink, C. Payne. Just thinking about exercise makes me serve more food. Physical activity and calorie compensation. Appetite, 56, Issue 2, April 2011, Pages 332-335. Results …indicate that simply reading about physical activity leads participants to compensate by serving themselves more snacks.

13 Sometimes we do not consider the unstated and completely opposite implicit assumptions : Warning away from restaurants – Implicit Assumption is undercompensation. Advocacy of Breakfast – Implicit assumption is overcompensation.

14 Schlundt et al. The role of breakfast in the treatment of obesity: a randomized clinical trial. Am J Clin Nutr 1992 Mar;55(3):645-51 Fifty-two moderately obese adult women were stratified according to their baseline breakfast-eating habits and randomly assigned a weight-loss program. The no-breakfast group ate two meals per day and the breakfast group ate three meals per day. After 12-wk, this treatment-by-strata-by-time interaction effect (P less than 0.06) suggests that those who had to make the most substantial changes in eating habits to comply with the program achieved better results. Does Eating Breakfast Promote Weight Loss?

15 Randomized Experiment of Breakfast and Total Day Energy Intake (Children) Kral TV, Whiteford LM, Heo M, Faith MS. Effects of eating breakfast compared with skipping breakfast on ratings of appetite and intake at subsequent meals in 8- to 10- y-old children. Am J Clin Nutr. 2011 Feb;93(2):284-91.

16 Randomized Experiment of Breakfast and Total Day Energy Intake (Young Adults) David A. Levitsky & Carly Pacanowski. Skipping breakfast results in reduced daily energy intake: Experimental evidence. Public Health Nutrition. In press.

17 Outline 1.Why we need to study EB. 2.Key Scientific Question. 3.Study duration/time-frame. 4.Selecting the endpoints. 5.Concerns about measurement error. 6.The value of quasi- and natural-experiments. 7.The possibility of true randomization should not be underestimated.

18 The Overall Question at the Broadest Level When one manipulates one aspect of energy intake or expenditure, what is the total effect (if any) on energy stores, and what are the factors and mechanisms influencing that total effect?

19 Outline 1.Why we need to study EB. 2.Key Scientific Question. 3.Study duration/time-frame. 4.Selecting the endpoints. 5.Concerns about measurement error. 6.The value of quasi- and natural-experiments. 7.The possibility of true randomization should not be underestimated.

20

21 Do calorie-controlled portion sizes of snacks reduce energy intake? Stroebele, Ogden, & Hill. Appetite 52 (2009) 793–796 52 (2009).

22 Learned Compensation in Humans

23 Outline 1.Why we need to study EB. 2.Key Scientific Question. 3.Study duration/time-frame. 4.Selecting the endpoints. 5.Concerns about measurement error. 6.The value of quasi- and natural-experiments. 7.The possibility of true randomization should not be underestimated.

24 The Importance on Non-Surrogate Variables Faith, Fontaine, Baskin, & Allison. Psychological Bulletin. 2007

25 Outline 1.Why we need to study EB. 2.Key Scientific Question. 3.Study duration/time-frame. 4.Selecting the endpoints. 5.Concerns about measurement error. 6.The value of quasi- and natural-experiments. 7.The possibility of true randomization should not be underestimated.

26 Correlated (non-random) Errors Harnack L, Himes JH, Anliker J, et al. Intervention-related bias in reporting of food intake by fifth grade children participating in an obesity prevention study. Am J Epidemiol 2004;160:1117–21.

27 Outline 1.Why we need to study EB. 2.Key Scientific Question. 3.Study duration/time-frame. 4.Selecting the endpoints. 5.Concerns about measurement error. 6.The value of quasi- and natural-experiments. 7.The possibility of true randomization should not be underestimated.

28 Quasi-Randomization: Holt Adoption Study Fontaine KR, Robertson HT, Holst C, Desmond R, Stunkard AJ, Sørensen TI, Allison DB. Is socioeconomic status of the rearing environment causally related to obesity in the offspring? PLoS One. 2011;6(11):e27692.

29 Roommate Randomization Each extra kg your roommate weighed before freshman year was associated with roughly.05 to.10 kg less weight for you.

30 Non-Random Assignment & Confounding The Lanarkshire Milk Experiment: In the spring of 1930, a large scale nutritional was carried out in the schools of Lanarkshire. For four months, 5000 children received raw milk, 5000 received pasteurized milk, and 10,000 were controls. DVs: Height & Weight Assignment: Teachers broke from randomization. Results: No significant differences. WHAT WENT WRONG? Student. The Lanarkshire Milk Experiment. Biometrika, Vol. 23, No. 3/4 (Dec., 1931), pp. 398-406.

31 Outline 1.Why we need to study EB. 2.Key Scientific Question. 3.Study duration/time-frame. 4.Selecting the endpoints. 5.Concerns about measurement error. 6.The value of quasi- and natural-experiments. 7.The possibility of true randomization should not be underestimated.

32 Why think? Why not try the experiment?” John Hunter, Letter to Edward Jenner, August 2, 1775. A rhetorical slight of hand is sometimes used to dismiss RCTs. Don’t buy it. Allison DB. Int J Obes 2011 Apr;35(4):464- 71. Evidence, discourse and values in obesity-oriented policy: menu labeling as a conversation starter.

33 Breakfast Revisited: Stay tuned…..

34 Does Breast Feeding Protect Against Obesity? an RCT – Results at 6.5 years Kramer et al. Am J Clin Nutr. 2007 Dec;86(6):1717-21.

35 Prevalence of BMI > 35

36 To Sum Up: 1.People often react (compensate) to a manipulation of one aspect of their energy intake or expenditure by modifying another aspect. 2.The magnitude and even direction of compnesation can vary substantially as a function of the manipulation and circumstances. 3.Long-term compensation responses are not necessarily the same as short-term compensation responses. 4.We cannot yet reliably predict compensation responses and weight changes in response to manipulations of single components of energy balance. 5.Therefore, we must do the experiments to find out. 6.And, the experiments can indeed be done.

37 Peavine Falls, Oak Mountain Park, Al From: http://www.encyclopediaofalabama.org/face/Multimedia.jsp?id=m-2898 High Falls, Moss Rock Preserve, Al From: http://farm3.static.flickr.com/2766/4226784012_7a1133a0e9.jpg “…let us take this path through the woods…” Jean-Jacques Rousseau


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