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Analysis

Making progress on the global crisis of obesity and weight management

BMJ 2018; 361 doi: https://doi.org/10.1136/bmj.k2538 (Published 13 June 2018) Cite this as: BMJ 2018;361:k2538

Food for thought

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The role of phenotypic plasticity and palatability

Lean and colleagues article (1) on obesity fails to give sufficient acknowledgement to the role of palatability and phenotypic plasticity in the current obesity epidemic.

The high palatability of modern processed foods, to a large extent, is the consequence of added sugar (2,3). For example, fats and oils are relatively unpalatable but the addition of a small amount of sugar gives rise to a substantial increase in hedonic preference ratings (2) and therefore the likelihood of overconsumption.

Epigenetic transgenerational inheritance plays a role in evolutionary change (4,5,6) and is almost certainly a factor behind the apparent evolution of modern man in to a fatter “species” and obesity’s resistance to “treatment”.

The greatly enhanced palatability of the modern food environment is a significant environmental change and some behaviours of the obese appear to be adaptive to this new environment. For example, the obese have a lower preference for sweetness (7), under respond to food deprivation (8) and are more likely to skip meals (9). A recent study indicates that future generations also exposed to this obesogenic nutritional environment may have a lower risk of metabolic disorders also due to epigenetic adaptations (10).

I agree that the current epidemic will only be curtailed by regulation and taxation of the food environment but as epigenetic changes can persist through generations significant beneficial change may take more than one generation.

References:
1. Lean M, Astrup A, Roberts S. Making progress on the global crisis of obesity and weight management. BMJ 2018;361:k2538.
2. Bradley PJ. Pathophysiology of Obesity. Lancet 1993;341:641.
3. Bradley PJ. Pathophysiology of Obesity. Lancet 1992;340:848.
4. Skinner MK, Gurerrero-Bosagna C, Haque MM, Nilsson EE, Koop JAH, Knutie SA Clayton DH. Epigenetics and the Evolution of Darwin’s Finches. Genome Biol. Evol. 2014;6(8):1972-1989.
5. Osborne A. The role of epigenetics in human evolution. Bioscience Horizons 2017;10:1-8.
6. Price T, Qvarnstrom A, Irwin DE. The role of phenotypic plasticity in driving genetic evolution. Proc Biol Sci 2003;270(1523):1433-1440.
7. Drewnowski A, Brunzel JD, Sande K, Iverius PH, Greenwood MRC. Sweet Tooth Reconsidered: Taste Responsiveness in Human Obesity. Physiol Behav 1985;35:617-622.
8. Wooley OW, Wooley SC, Dunham RB. Deprivation, expectation and threat: Effects on salivation in obese and nonobese. Physiol Behav 1976;17(2):187-93.
9. Mota J, Fidalgo F, Silva R, Ribeiro JC, Santos R, Carvalho J, Santos MP. Relationship between physical activity, obesity and meal frequency in adolescents. Ann Hum Behav 2008;35(1):1-10.
10. Tait AH, Raubenheimer D, Green MP, Cupido CL, Gluckman PD, Vickers MH. Successive Generations in a Rat Model Respond Differently to a Constant Obesogenic Environment. PLoS ONE 2015;10(7):e0129779.

Competing interests: No competing interests

02 July 2018
Patrick J Bradley
Retired Medical Practitioner
Wollongong Australia