Interview: Susan Birch talks about The Health Detective's Handbook

Susan Birch began studying exercise and nutrition science in 1986 and quickly found her passion. She has written The Health Detective’s Handbook, a guide to reconnecting with the body and understanding what it needs to thrive. The book combines science, practical application and real-life stories to help readers make informed decisions, care for their body with respect, and find their own path to lifelong wellness. Susan talks to NZ Booklovers.

Tell us a little about your book.

The Health Detective’s Handbook is about helping people understand how their bodies work and why things can go wrong. Many people struggle with fatigue, weight gain, blood sugar problems, digestive issues, poor sleep or hormonal symptoms and are given advice about what they should eat or do, without really understanding what’s driving those problems.

This isn't another diet book or a set of rules to follow. I explain how different systems in the body interact, and why the same diet, exercise programme or health advice can produce very different results in different people. I also teach readers how to look for patterns and clues rather than focusing on one symptom or one blood test in isolation.

My aim is to give people enough knowledge to ask better questions and make more informed decisions about their health.

What inspired you to write The Health Detective’s Handbook?

I started studying exercise and nutrition science in 1986, and I’ve never really stopped. Over the years I became increasingly interested in why some people could seemingly do everything “right” and still struggle with their health, while others responded quite differently to the same advice.

Working with clients taught me that symptoms rarely exist in isolation. Fatigue, weight gain, poor sleep, digestive problems, blood sugar changes and hormonal symptoms can all be clues to what’s happening elsewhere in the body. I became fascinated by learning how to put those clues together.

My own health journey has also influenced the way I think. I’ve learned that knowing a lot about nutrition and exercise doesn’t mean you’ll always have the answers, and sometimes you have to keep asking questions when the pieces don’t seem to fit.

I wrote the book because I wanted to share what I’ve learned over nearly 40 years and encourage people to take a different approach to their health – to become curious about what their body is telling them and ask, “Why is this happening?”

What research was involved?

The research behind this book spans 40 years. A lot has changed over that time. I began studying exercise and nutrition science in 1986 and have continued studying ever since, moving into functional medicine, blood chemistry analysis and the way different systems in the body interact.

As I wrote each section, I went back through the science and checked the research behind it. I wanted to understand the mechanisms, not simply repeat commonly accepted health advice. That meant looking at published research, textbooks and clinical literature, and sometimes following a question down a very deep rabbit hole.

My work with clients has also been an important part of that learning. When you see the same patterns appearing repeatedly in people, it raises questions that send you back to the research looking for explanations.

One of the challenges was taking all that science and turning it into something people without a medical or scientific background could understand and use. I wanted the book to be scientifically grounded, but also practical and readable.

What was your routine or process when writing this book?

I didn’t really have a traditional writing routine. I was working with clients and continuing my own study while I wrote, so the book developed alongside my everyday work.

I would often start with a concept I wanted people to understand, research it in depth, then try to explain it in plain language. That was probably the hardest part. It’s one thing to understand something yourself; it is another to explain complex physiology without either oversimplifying it or losing the reader.

I also rewrote a lot. I would come back to sections and think, “No, that still doesn’t explain it properly,” and start again. The illustrations became an important part of that process because sometimes a picture could explain in a few seconds what I had spent several pages trying to put into words.

It was a long process, fitted around work and life, but gradually all those individual pieces came together as a book.

If a soundtrack were made to accompany this book, name a song or two you would include.

Light of a Clear Blue Morning by Dolly Parton. I’ve always liked its sense of hope and resilience – that however difficult the journey becomes, there can be light ahead. Writing this book has been quite a journey, so it seems fitting. I had already chosen the song before learning of Dolly’s death, which makes it feel particularly poignant now.

What did you enjoy most about writing this book?

I love learning, asking questions and working out how the pieces fit together, so I enjoyed that part enormously. There was something very satisfying about taking an idea that seemed complicated and finally finding a way to explain it simply, whether through words or an illustration.

Most of all, I liked knowing that what I had learned over so many years was becoming something other people could use to better understand their own health.

What did you do to celebrate finishing it?

I’m not sure I really did! Finishing the writing turned out not to be the end. There was editing, illustrations, proofreading, formatting, printing and then all the work involved in actually launching a book. That’s a whole new learning curve.

I think the real celebration will be the book launch in Rotorua on 28 August, when I can finally have a glass of bubbles, look around at the people who have supported and encouraged me, and think, “I actually did it.”

What is your favourite book you’ve read this year and why?

I have to confess I haven’t read a book for quite some time. While I was writing The Health Detective’s Handbook, I spent so many hours reading research, scientific papers and my own manuscript over and over again that the last thing I wanted to do at the end of the day was pick up another book! I’m hoping I’ll rediscover reading for pleasure now that mine is finally finished.

What’s next on the agenda for you?

I already have two more books I want to finish. The next one will focus on understanding blood chemistry and what our blood test results can tell us when we look beyond whether a result simply falls inside or outside the laboratory reference range.

After that, I want to write a book about cholesterol and cardiovascular disease. It’s an area I’ve studied for many years and one that has become much more personal to me.

I’m also working towards turning my health masterclass into an online programme. Apparently finishing one book hasn’t cured me of wanting to explain how the body works!

Health Detective Publishing