The Protein Code: What If the Food on Your Plate Is Part of the Reason You Wake Up Tired?

by Rebecca Goodwill

What If the Food on Your Plate Is Part of the Reason You Wake Up Tired?The Protein Code is an investigation into what protein does inside your body, what falls apart when it isn't there, and who decided to take it off your plate in the first place.

Drawing on physiology, food industry history, and behavioral neuroscience, the book makes a case that is hard to argue with once you've heard modern food systems are extraordinarily good at delivering energy, and remarkably poor at delivering the nutrients the human body actually runs on.


This book is for you You eat "well" but still feel depletedYour brain feels foggy by mid-afternoonYou crave sugar, salt, or coffee to keep goingYou've been told your tests are normalSomething in your diet feels off, but no one can name it

Inside this The Protein Code walks you through the biology of hunger and satiety — why your body keeps asking for more even when you've eaten enough, and what it's actually looking for. You'll learn how food industry decisions made decades ago shaped what ended up on your plate, why calorie counts tell you almost nothing about whether your body is getting what it needs, and how protein interacts with hormones, brain chemistry, and energy regulation in ways that most nutrition advice never mentions.

This isn't a diet book. There are no elaborate meal plans, no before-and-after promises, and no rules to follow. It's an in depth explanation — the kind most people never get — of why the body behaves the way it does when it's running low on something essential. By the end, you won't just understand why you're tired. You'll understand the system that made sure you stayed that way.

232 pages, Kindle Edition

Published June 6, 2026

About the author

Rebecca Goodwill studies chronic fatigue through the lens of stress physiology and nervous system regulation. After struggling with persistent exhaustion for years herself, she turned to neuroscience, psychology, and close observation to understand what she was fighting.

Rather than framing fatigue as a mindset or discipline problem, her work focuses on biological limits, system overload, and what sustainable recovery actually requires

Reviews

[Amber · Rating 5 out of 5]

Thanks to Rebecca Goodwill for the ARC! I really enjoyed the amount of research, personal stories and organization of the book. I took notes while reading and I'm excited to apply them to my everyday life to start feeling more focused, energized and overall health improvement! I will definitely be buying Rebecca Goodwill's other book Always tired.

[J.P. Cawood · Rating 4 out of 5]

Easy to read guide to clean eating with a brief history of how we've come to eat more processed food and why. It gives you guidance on how much protein you should eat for your body, what kinds of protein to eat, and shopping lists to make it easy. As someone who has done the keto diet, I can tell the difference when I eat more protein vs carbs. Get this book if you want more energy, less brain fog, and weight loss.

[D.Ann · Rating 5 out of 5]

In this sequel to Always Tired, author Rebecca Goodwill expands her original concepts about the state of exhaustion prevalent in our current culture, homing in on the specific requirements our bodies have regarding protein that many people may be unaware of. The Protein Code: The Science of Why the Modern Diet Keeps You Tired is more than a simple rally cry to increase protein intake. Social media inundates many of us with that message daily. But how much do we know about the reasons why it is needed and why it affects our energy specifically? Goodwill breaks down the science in an accessible way, ensuring that her purpose for the book is, “…primarily for tired people, not fitness enthusiasts or lifestyle purists.” She shows what protein does to the mind and body, how it does it, and why these processes are necessary for physical health and longevity. She compares what happens to the body and brain when they do not have adequate protein and when they do.

Goodwill also goes beyond the science and includes cultural challenges that can overwhelm us with food noise, how regulatory systems operate in ways to manipulate citizen’s nutritional choices, and the connections between marketing and packaging designs that ultimately affect what kind of food people eat and in what amounts. The book also shares the counter-cultural narrative that exhaustion can have physiological and biological root causes. It often has nothing to do with laziness, a lack of willpower, or other personal failings.

While the information in the book may be repetitive if you work in the health or fitness industry, Goodwill is clear that is not her target audience. So, if you are not a medical professional or a health and exercise devotee, but you are exhausted and tired of being tired, then The Protein Code can shed some light on your situation that you most likely have not been exposed to before. Goodwill conveys why protein intake is valuable on a personal level. She guides the reader through learning the science, then gives real-world examples of how to put the information into action. (Pay attention to her stylistic choice of using italics to signal the movement from science to practical advice.)

By sharing the body and brain science, Goodwill helps us to better understand how our mundane, daily food choices have a larger effect on our overall well-being and long-term neurological health than is commonly recognized. She also explains how to identify the pitfalls that the food industry purposely places in our way. The Protein Code helps you understand the food environment we make decisions in. This gives readers the currency needed to make lifestyle changes and create new habits. Sometimes the difference between knowing what we should do and having the desire to do it is the difference between being told what to do and understanding why we need to and why those reasons are valid. Once you understand the pieces of that puzzle, and what your body and brain are truly starving for, you can change your strategy to feel better long-term.

*I received a complimentary copy of this book from the author. I voluntarily chose to review it, and all opinions expressed are my own.

[Laurence French · Rating 5 out of 5]

'The Protein Code' by Rebecca Goodwill is the follow-up to her first book, 'Always Tired'. In that book she explored the reasons that some people feel permanently exhausted, worn-out, tired and overwhelmed by life's problems. In 'The Protein Code' she isolates one particular reason - diet - and the lack of protein and amino acids that characterise the daily diet of many people.
Drawing on extensive and thorough research, as well as anecdotes from her own life and family, she analyses the reasons that so many people have a poor diet and asks the question ' ... how exactly does what's on your plate dictate how you feel when you wake up?' In doing so, she reveals why modern food is great at packing in the calories, but often leaves our bodies lacking in the fuel we actually need. She warns us not to be fooled by advertising slogans and packaging that would have you believe that you are feeding your family a healthy diet when, in fact, you are feeding them a diet that is lacking in vital ingredients.
She explores the scams played on us by big business where we have sacrificed nutrition and healthy diets for artificial flavours, long shelf-life, visual appeal and ... massive profits for the corporate sector. Health has given way to wealth.
Interspersed with all this are plenty of ideas, suggestions and valuable advice on how to correct the 'problem of a poor diet'. As with 'Always Tired', this is a very readable book that will help a lot of people to understand the reasons for their tiredness and lethargy as a result of a deficient diet. I thoroughly recommend it.

[Barbara · Rating 5 out of 5]

Let’s face it, being constantly tired is an epidemic of the modern era: we wake up tired, function tired, and go to sleep tired, just to start all over the next day. What if I told you part of the problem is what we eat? Rebecca Goodwill does just that in her book “The Protein Code”, a follow up of her first book, “Always Tired”, and it’s just as good as the first one.
Again, she goes deep into investigating the causes of modern fatigue but this time it’s from a nutritional standpoint, explaining how the starch-rich diet was sold to us because it was convenient for others and how sugar and additives found in convenience food are a poor substitute for what our body really needs.
Admittedly, it resonated with me less compared to the first one as my diet is already quite rich in protein and I also live in Italy where, though it exists, the scourge of chemical-filled convenience food is far from the heights it has reached in other countries. Still, a lot of the tips Rebecca gives are useful to eat more mindfully and try and incorporate more protein and less starch into your daily eating plan, and the whole book is written scientifically but still easy to understand for the lay person - almost as if you were having a chat with a friend.
So if you are suffering from chronic fatigue, want to improve your eating habits, or are simply curious about nutrition, definitely pick up this book!

[Mark · Rating 5 out of 5]

I jumped at the chance to review an Advanced Reader Copy of The Protein Code because I've been dealing with exactly the issues this book describes: chronic fatigue, mid‑afternoon brain fog, creeping sugar reliance, and “normal” lab results. What I appreciated most is that this isn’t another diet plan or motivational pep talk. Goodwill explains, in clear language, how modern food leaves us overfed on calories but under-supplied on the raw materials our brains and bodies actually need, especially protein and adequate hydration.

The book reframed my tiredness and low motivation as a resource problem rather than a willpower problem, showing how low amino acid availability, sugar spikes, and even mild dehydration push the brain into “power‑saving mode.” Her explanations of sugar as a fast-acting tranquilizer for a stressed brain, and of how protein underpins mood, sleep, and focus, made my own patterns make sense and gave me practical levers (protein‑anchored meals, a smarter approach to sweets, and more deliberate hydration) without strict rules or meal plans. If you’re generally health‑conscious but still exhausted, struggling with chronic brain fog, and routinely turning to extra cups of coffee and/or sugary snacks to fight the urge for an afternoon nap, this is a very worthwhile read.

[Amanda Milne · Rating 5 out of 5]

I never realized how protein can really help your body until I read this book. Rebecca explained the effect of protein - when, why, how we should eat it in really simple terms (not alot of medical terminology in it).
Rebecca just doesn't talk about protein in the book, she also talks about sugar, the food pyramid, energy levels and how they relate to protein.
I am not a big fan of ultra processed foods (UPF), I don't like the taste. Now that I understand what UPF does to the body, I will be staying away from it.
This is a great book for anyone wanting to learn how protein (a whole food) can assist your body to be the best it can be!!! An amazing read full of so much knowledge and tips I will introduce into my life.

[Kirsten · Rating 5 out of 5]

As someone who’s actively trying to lose weight, I got a lot out of The Protein Code by Rebecca Goodwill. She makes a lot of positive, realistic points about the role protein plays in overall health, and I appreciated that the advice felt practical instead of overwhelming.

I also really liked how it ties back to Always Tired. Instead of feeling like a repeat, it builds on the ideas from that book and shows how protein can be one of the missing pieces when it comes to energy, recovery, and feeling your best.

I finished this feeling more informed and with a few changes I actually want to make. If you’re trying to improve your health or just want a better understanding of nutrition without all the fad diet noise

[Ashley Manson · Rating 5 out of 5]

I love how clear Rebecca write her books.
She writes them in a way that makes it easy to understand what I need to do.
The only reason it took me several days to read was because…I was tired!!! I was so tired I was struggling to get some reading time in.
Now thanks to her book I know why. I know what I’ve been missing and how much my diet is effecting me. It answered so many questions and concerns I had.
With both her books I can really see a lot of people feeling more awake and happy.
She even includes a guide on how to slowly incorporate the diet. I love it.
I highly recommend reading this book and her “Always Tired” book.

[Melissa Johns · Rating 5 out of 5]

PERFECT!
This book talks to us regular people - the ones that don't have hours to spend in the kitchen. I started executing some of the changes notice an immediate difference. I knew protein was important... but after reading this, I realize I had no idea.

Strongly recommend for anyone that works late and struggles with the mental load of cooking when they get home.

Her first book was wonderful, and this one is just as good!

[Katie O'Connor · Rating 4 out of 5]

This is a fascinating book. I learned a ton of information on how the body works.

I'll be using this info to modify my diet.

Well worth the time and effort to read.