Lillian Wilson

The Sleep Diet by Carmel Harrington

Discover how sleep affects metabolism and weight and how you can achieve optimal sleep with ‘The Sleep Diet.’

The Sleep Diet

The book has gotten 3.88 ⭐️ on GoodReads.

Did you know that 62% of people in the world have problems sleeping and 39% are overweight? That’s pretty shocking, but is there any connection?

In her book ‘The Sleep Diet,’ Carmel Harrington, a renowned sleep scientist, demonstrates the fine line of sleep-weight correlation. In this review, we will delve into the compelling insights presented in the book and explore how the authors shed light on this critical topic.

Author’s background

Carmel Harrington (PhD, LLB, BSc, DipEd) is an Australian sleep medicine research scientist.

Carmel Harrington (r)

She is extensively experienced in the field of sleep medicine, with a focus on studying the impact of sleep on metabolic function, sleep-disordered breathing, autonomic dysfunction, and pediatric sleep. Her academic accomplishments include a PhD in Sleep and Respiratory Medicine and Masters of Statistics in Public Health, both earned at the University of Sydney.

What is the book about?

In ‘The Sleep Diet,’ Dr. Carmel Harrington presents a groundbreaking exploration of the crucial link between insufficient sleep and nutrition. Drawing from the latest research on sleep and nutrition, Dr. Harrington unveils the scientific mechanisms behind the effects of sleep deprivation on our bodies. She sheds light on how it significantly impacts our appetite-controlling hormones, metabolism, and cognitive functions, leading to weight gain and hindering weight loss efforts.

The book is divided into three parts with the first one delving into the problem of inadequate sleep and highlighting the vital functions of sleep. Dr. Harrington discusses its role in regulating metabolism as well as its significance in relation to diabetes and its influence on our behaviour.

Moving to Part II, ‘I Understand The Importance Of Sleep – What Now?’ readers are offered practical guidance on achieving a good night’s sleep. Dr. Harrington emphasises the importance of our biological clock and presents good sleep practices (also known as sleep hygiene).

Finally, Part III, ‘The Program,’ focuses on the essential connection between eating, sleeping, and weight. Dr. Harrington presents a personalised sleep program, detailing how readers can develop healthy sleep habits.

Table of contents

  • Cover
  • About the book
  • Dedication
  • Part 1 – The Importance Of Sleep
  • 1. The problem
  • 2. The vital functions of sleep
  • 3. Sleep, metabolism and our appetite hormones
  • 4. A special case – sleep and diabetes
  • 5. How sleep affects our behaviour
  • 6. What is sleep and what does healthy sleep look like?
  • Part 2 – I Understand The Importance Of Sleep – What Now?
  • 7. How to get a good night’s sleep – the importance of our biological clock
  • 8. Good sleep practices (or good sleep hygiene)
  • 9. Sleep disorders
  • 10. Sleep-related breathing disorders
  • Part 3 – The Program
  • 11. The connection between eating, sleeping and weight
  • 12. Your personal sleep program
  • Conclusion
  • Appendix
  • Index
  • Acknowledgements
  • About the author
  • Copyright page

Key takeaways from ‘The Sleep Diet’

1Sleep and weight management share a sufficient connection

‘The Sleep Diet’ highlights the significant connection between sleep and weight management. Lack of sufficient sleep can negatively impact both physical and biological health, leading to weight gain and increased appetite. The author cites scientific research that reveals that inadequate sleep disrupts appetite-controlling hormones, resulting in heightened feelings of hunger and a preference for calorie-dense foods. By understanding the crucial role of sleep in metabolism and hormonal balance, readers can make informed decisions to improve sleep patterns and support successful weight loss efforts.

2Sleep affects our behaviour

In the chapter ‘How sleep affects our behaviour,’ the author emphasises the crucial role of adequate sleep in overall well-being. Chronic sleep deprivation not only affects our metabolism and appetite hormones but also impairs decision-making, increases mood swings, and reduces motivation. Dr. Harrington provides an example of one of her patients, who struggled to lose weight despite their motivation, illustrating how lack of sleep undermines efforts to maintain a healthy lifestyle. Understanding the interdependence of nutrition, exercise, and sleep is essential for achieving lasting weight loss and improving overall health.

3Sleep deprivation can increase the likelihood of type 2 diabetes development

Sleep plays a crucial role in maintaining a healthy metabolism and preventing the development of type 2 diabetes. Studies have consistently shown that poor sleep quality or insufficient sleep duration can lead to a state of biological stress, causing an increase in cortisol levels and negatively affecting glucose metabolism. This, in turn, increases the risk of developing type 2 diabetes or the pre-diabetic state.

Strengths and weaknesses, according to readers’ reviews


  • Explains the science of sleep and its interaction with diet in easily understandable terms for the general reader.

  • Provides practical principles that can be easily applied to maintain a healthy weight and overall well-being.

  • Helps readers understand the myths surrounding fad diets and highlights the importance of sleep in achieving the correct weight.


  • The book can be repetitive in certain areas, which may reduce the overall reading experience.

Best quotes from ‘The Sleep Diet’

“Sleep is the golden chain that ties health and our bodies together.”
“Our ability and determination to diet are directly affected by the amount of sleep we have each night. This is because sleep, or lack of it, determines our behavioural mood and is the major contributor to how well we think, plan and act.”
“Unfortunately for those women who had shorter sleep, their weight situation did not improve – in fact, it got worse. Women who, at the start of the study, slept less than five hours put on much more weight than those women who slept 7–8 hours per night. It was found that these women had more than a 30 per cent increased risk of major weight gain and obesity over the 16-year period – and this increase was calculated while taking into account caloric intake and physical exercise.”

Final takeaway

In ‘The Sleep Diet,’ Dr. Carmel Harrington skillfully illuminates the intricate connection between sleep and weight management. Through scientific research, the book reveals the profound impact of sleep deprivation on appetite-controlling hormones, metabolism, and cognitive functions, leading to weight gain and hindering weight loss efforts.

With practical guidance and personaliіed sleep programs, this book offers valuable insights to anyone seeking to improve their overall well-being, making it a must-read for those looking to understand the importance of sleep in achieving and maintaining a healthy lifestyle.

Where to buy

You may purchase a Kindle version of ‘The Sleep Diet’ on Amazon at the best price.

Healthypedia FAQ

Yes, 'The Sleep Diet' offers practical guidance and good sleep practices to achieve a good night's sleep, emphasising the significance of our biological clock.

Yes, 'The Sleep Diet' dispels myths surrounding fad diets and emphasizes the importance of sleep in achieving and maintaining the correct weight.

Sleep and weight management are closely linked. Inadequate sleep disrupts appetite-controlling hormones, leading to increased feelings of hunger and a preference for calorie-dense foods, which can contribute to weight gain.

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