Obesity: the gene-environment debate

Mind Over Chatter

What role do our genes play in influencing our body weight and what we like to eat? Why do some people gain weight more easily than others, and is it all down to genes or are there other factors at play? In this episode, we talked with a clinician and scientist Sadaf Farooqi, health psychologist Theresa Marteau, and geographer Thomas Burgoine about the multitude of factors that go into influencing our eating behaviours. Along the way, we hear about the crucial importance of the environment in influencing our eating behaviour, including “zoning” - the effort to keep fast food outlets no more than 400 yards from schools, and learn how our food has become more calorific over the past 20 to 30 years. Our guests discuss how ultimately, communicating information about obesity doesn’t necessarily change our behaviour towards food, as we are much more influenced by our genes and environment than what's inside our heads.

This episode was produced by Nick Saffell, James Dolan, Naomi Clements-Brod and Annie Thwaite.

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Timestamps:

[00:00] - Introductions

[01:00] - A bit about the guests’ research

[02:10] - Defining obesity and what it means to be obese

[02:45] - Along with diabetes, how does obesity impact our health?

[03:45] - What proportion of the global population are obese?

[04:25] - How these

[05:25] - The many factors that contribute to obesity (genes and how our genes respond to the environment)

[06:40] - Patterns of obesity. The pandemic, neighbourhoods, inequality, and how income levels affect childhood obesity?

[10:40] - How low income and poverty drains our mental capacity for cognitive tasks

[12:05] - How small amounts of income are given to the poorest households decreases stress and improves diets.

[12:55] - The calorie paradox and energy-poor foods. The role of processed foods.

[14:25] - What would a ’healthy’ country/neighbourhood look like

[15:25] - Time for a recap

[19:15] - What can we do at a policy level? Could hospitals be the perfect ‘role models’?

[20:30] - Should policymakers be setting the food environment? Looking at examples like the experiments in Singapore.

[21:40] - Translating research to improve the food environment. Changing worksite cafeterias. Reducing the amount of higher calorie meals available. Cutting portions sizes of higher calorie meals.

[24:00] - How the size of wine glasses affects how much people are drinking. What this means in terms of calorie consumption.

[25:30] - The amount of evidence that is needed for public health interventions (public vs commercial sector)

[26:40] - What about education, the school environment, zoning, access to fast food, and education around obesity

[29:40] - How do we respond to risks - does information change our behaviour? Does the ‘5 A Day’ work?

[31:40] - From a psychology perspective, does education work to change our behaviour? [32:20] - What about from a biological and genetic perspective? The role of the environment.

[34:00] - Is eating behaviour voluntary? How much is it down to your genes? Using experiments with twins to understand the gene-environment interaction.

[36:00] - The gene-environment interaction example from ethnic groups that migrate to the USA and the increased level of obesity.

[38:00] - Genetic disposition to eat and the way in which environment influences our behaviour.

[39:20] - It isn’t genes vs environment, it’s genes and environment. Being thin is inheritable. There is the biology behind what foods you choose. Your brain will prefer high fat or high-calorie food.

[42:15] - Where can we intervene. It’s about changing environments. Our policy has to both influence our environment and what we’re exposed to. What are all of the factors?

[44:10] - The number of policies and strategies that have been tried. What does this mean for political science?

[42:15] - Some successful examples - the sugar tax and reduction in sugar, rather than volume of sales. But what we need is to go at scale with more than one intervention.

[47:15] - Time for another recap.

[52:55] - Thinking about how we treat obesity? We need to think about the biology and genes behind how we treat obesity.

[55:20] - Is the food environment overwhelming our biology and psychology. Who’s winning… the corporations. Products are now too hard to resist. The trade-off between health and wealth.

[58:45] - How do ‘we’ think about individual responsibility for obesity?

[1:02:35] - Let's break this episode down and close this thing out.

Guests

Dr. Thomas Burgoine - @thomasburgoine

Thomas studies neighbourhood food environments and their effects on dietary behaviours, diet, diet-related disease, and inequalities therein, mostly through linking large scientific datasets (e.g. the Fenland Study, UK Biobank) to administrative and routinely collected data. He is currently researching existing applications of the English planning system to create healthier neighbourhoods, and evaluating takeaway food outlet “exclusion zones” around schools as a form of public health intervention for population-level obesity prevention.

Professor Sadaf Farooqi - @Farooqi_Lab

Professor of Metabolism and Medicine at the University of Cambridge. Sadaf is an Clinician Scientist who has made seminal contributions to understanding the genetic and physiological mechanisms that underlie obesity and its complications. The work of Sadaf Farooqi and her colleagues has fundamentally altered the understanding of how body weight is regulated. With colleagues, she discovered and characterised the first genetic disorders that cause severe childhood obesity and established that the principal driver of obesity in these conditions was a failure of the control of appetite.

Professor Theresa Marteau - @MarteauTM

Director of Behaviour and Health Research Unit, Dept of Health and Primary Care, University of Cambridge. Her research focuses on the development and evaluation of interventions to change behaviour (principally food, tobacco, and alcohol consumption) to improve population health and reduce health inequalities, with a particular focus on targeting non-conscious processes.

Additional notes:

A list of papers and studies that are referenced during the episode.

1. Marteau TM, Chater N, Garnett EE. Changing Behaviour for Net Zero 2050 BMJ 2021;375:n2293 https://doi.org/10.1136/bmj.n2293
2. Marteau TM, Rutter H, Marmot M Changing behaviour: an essential component of tackling health inequalities BMJ 2021;372:n332 https://www.bmj.com/content/372/bmj.n332
3. Reynolds JP, Ventsel M, Kosīte D, Rigby Dames B, Brocklebank L, Masterson S, Pechey E, Pilling M, Pechey R, Hollands GJ, Marteau TM. Impact of decreasing the proportion of higher energy foods and reducing portion sizes on energy purchased in worksite cafeterias: a stepped-wedge randomised controlled trial. PLoS Med 18(9): e1003743 https://doi.org/10.1371/journal.pmed.1003743
4. Codling S*, Mantzari E*, Pechey R, Hollands GJ, Pilling M, Marteau TM. Impact of bottle size on in home consumption of wine: a randomised controlled trial *Joint first authors Addiction 2020 Apr 09 https://doi.org/10.1111/add.15042
5. Pilling M, Clarke N, Pechey R, Hollands GJ, Marteau TM. Wine glass size and sales: a mega-analysis of studies in bars and restaurants Addiction 2020 Jan 31

https://onlinelibrary.wiley.com/doi/abs/10.1111/add.14998

1. Reynolds JP, Stautz K, Pilling MA, van der Linden S, Marteau TM. Communicating the effectiveness and ineffectiveness of government policies and their impact on public support: A systematic review and meta-analysis. Royal Society Open Science Accepted for publication: 17.01.20

https://www.researchgate.net/deref/http%3A%2F%2Fdx.doi.org%2F10.1098%2Frsos.190522