A Conversation About Healthy Eating

250 Pages·2017·8.556 MB·English

by  Nicholas A. Lesica

WHAT coNsTITuTEs A HEALTHY dIET? MAINsTrEAM MEdIA ANd AdvErTIsErs
WouLd LIkE You To THINk THAT THE ANsWEr To THIs quEsTIoN Is
coMpLIcATEd ANd coNTrovErsIAL. BuT scIENcE, forTuNATELY, TELLs us
oTHErWIsE.
A Conversation about Healthy Eating brings together all the relevant science
about healthy eating in one place, and it’s exactly that – a conversation; an
informal discussion between a scientist and a friend about their eating habits,
keeping the science firmly rooted in everyday life. The conversation moves
from topics such as metabolism and digestion to gut bacteria, hormones,
neuroscience and the immune system. All of these concepts are explained in
accessible terms to help you understand the roles they play in maintaining a
healthy diet.
The conversation leads to the conclusion that staying lean and healthy simply
requires avoiding the overconsumption of processed foods. While this is, of
course, easier said than done, science also provides clear recommendations for A CONVERSATION ABOUT
how you can adapt your environment and lifestyle to make it possible.
HEALTHY EATING
Rather than simply presenting you with the principles of healthy eating, this
book will help you to develop a comprehensive understanding of the science
behind the principles, including the evolutionary facts that affect the way we eat
today. This understanding will allow you to ignore the noise in the media and to
move forward with a healthy lifestyle that work for you.
Nicholas A. Lesica is Wellcome Trust Senior Research Fellow at UCL. He is a
neuroscientist with an active research program dedicated to understanding
how the brain processes sensory information. He received his undergraduate
degree from MIT and his PhD from Harvard. During his research career, he
has led dozens of scientific studies and published numerous journal articles.
Cover design:
www.ironicitalics.com
Free open access versions available from
www.ucl.ac.uk/ucl-press £45.00
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A Conversation about Healthy Eating
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A Conversation about

Healthy Eating
Nicholas A. Lesica
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First published in 2017 by
UCL Press
University College London
Gower Street
London WC1E 6BT
Available to download free: www.ucl.ac.uk/ ucl- press
Text © Nicholas A. Lesica, 2017
A CIP catalogue record for this book is available
from The British Library.
This book is published under a Creative Commons Attribution Non-commercial
Non-derivative 4.0 International license (CC BY-NC-ND 4.0). This license
allows you to share, copy, distribute and transmit the work for personal and
non-commercial use providing author and publisher attribution is clearly stated.
Attribution should include the following information:
Nicholas A. Lesica, A Conversation about Healthy Eating. London, UCL Press, 2017.
https://doi.org/10.14324/111.9781911576754
Further details about CC BY licenses are available at http://creativecommons.org/
licenses/
ISBN: 978– 1– 911576– 77– 8 (Hbk.)
ISBN: 978– 1– 911576– 76– 1 (Pbk.)
ISBN: 978– 1– 911576– 75– 4 (PDF)
ISBN: 978– 1– 911576– 78– 5 (epub)
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DOI: https:// doi.org/10.14324/ 111.9781911576754
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Acknowledgements

I would like to thank the following people for their help during the writ-
ing and publishing process:
My wife Tara, for insisting that I do something useful for once and
supporting me throughout;
The organizers of the 2016 Accountability Strategy Summit, espe-
cially Marta, for helpful discussions;
My friends at the Dulwich Squash Club, especially Andy, Mikey P.,
Davey, Mikey A., Josh, Mark, Tomas, Giles and Pete, for their suggestions
and encouragement;
The spa team at the St. Pancras Renaissance Hotel, for providing
an oasis of calm in which much of the reading and thinking for this book
was done;
Chris and the rest of the team at UCL Press, for being open minded
about the non- traditional format.
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Contents

Introduction I 1
Introduction II 9
1. Metabolism 13
2. Inflammation 26
3. Calories in 39
4. Calories out 63
5. Gut bacteria 76
6. Processed foods 87
7. Interactions between the immune system and gut bacteria 102
8. Good and bad fats 119
9. Sugar and drinks 151
10. Diets 169
11. Daily rhythms and meal timing 182
12. Behavioral change 194
Notes 215
Glossary 222
References 225
Index 239
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Introduction I

OK, this is really more of a glorified preface but I wanted to be sure that
you didn’t skip it. I tend to skip prefaces because I prefer my experience of
a book to be unbiased. I don’t want to know anyone else’s thoughts about
a book – not even the author’s – until I’ve finished reading it and formed
thoughts of my own. But this approach does have its risks: sometimes my
expectations are wrong and I end up disappointed by a book that I might
have otherwise enjoyed if I’d been properly prepared for it (Trainspotting,
as it turns out, was not quite the ode to railways that I was hoping for . . .).
So that’s what this introduction is about: setting expectations.
Perhaps I should start with a bit of background. I’ve always enjoyed
eating but, until a few years ago, I’d never really thought very deeply
about my diet. Which is not to say that I’d never really worried about my
diet: like most people I was constantly watching my weight and stressed
about whether or not I was eating the right foods or the right amount
of food. But at some point I realized that I didn’t need to live with that
uncertainty. Like any physical system, the body is governed by rules that
determine how different inputs – for example, diets – are transformed
into different outputs – for example, health. To eliminate the stress asso-
ciated with eating, I simply needed to learn the rules that determine how
diet affects health and then use those rules to make systematic choices
about what I eat.
Easier said than done, right? It’s true that the rules that determine
how diet affects health are complicated but they’re not actually that com-
plicated. They only seem complicated when you try to infer them from
the information that you get through mass media. Much of the informa-
tion about diet and health in mass media is, of course, exaggerated if not
altogether incorrect but, even if it were accurate, the piecemeal nature of
it would still be a major problem. The different systems in the body and
brain that link diet and health are highly interdependent, so it’s impossi-
ble to understand how some of them work without understanding how
all of them work.
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