Obesity is one of the fastest developing public health problems and is now described as a worldwide epidemic. Diet has a key role in the development and maintenance of obesity, although what constitutes a ‘healthy diet’ is a contentious issue, with academics, educators, medics and decision-makers in governments still debating what are the best food and dietary behaviours to prevent nutrition-related diseases and promote health. Messages regarding healthy eating are sometimes misinterpreted by the media, adding to the confusion and leading the public to be sceptical of advice from nutrition ‘experts’.
This book is essentially a large literature review to identify dietary factors and circumstances that contribute to the development of obesity in the US and was funded by the Centres for Disease Control (CDC). The main aim of the book is to provide the evidence base to define those healthy-eating practices (foods and dietary behaviours) that should be supported and encouraged as well as those that should be discouraged in the general public. The focus of this book is on the prevention of obesity, rather than the management and treatment of those who are already obese as ‘The prevention of weight gain and maintenance of a healthy weight are likely to be easier, less expensive and potentially more effective than the treatment of obesity after it has fully developed’ (Gill, Reference Gill, King and Caterson2005). Energy expenditure influences on the development and maintenance of obesity are also beyond the scope of the book although another review on physical activity as a determinant of energy imbalance is available.
The book is divided into five chapters. Chapter 1 contains a brief introduction to the issue of obesity in the US, and some brief information related to the Obesity Prevention Network ((OPN) of which the authors are members) which operates within the CDC and whose main purpose is to help identify strategies for the prevention of obesity. Chapter 2 gives the reader a detailed account of the systematic search process undertaken, including extensive information on article abstraction and manuscript format. Chapter 3 defines the critical periods of obesity development throughout the lifespan. This is a stand-alone chapter which I felt could have been incorporated into the main body of text (chapter 4). Chapter 4, entitled ‘Dietary influences on energy balance’ is a large chapter and is subdivided into fifteen sections (Total calories, Energy density, Macronutrient intake, Minerals and vitamins, Vegetables and fruits, Sweetened beverages and fruit juices, Restaurant-prepared foods, Dietary patterns, Variety of foods, Reduced-fat food products, Portion size, Meal and snack patterns, Parenting influences, Breastfeeding and Food insecurity), while chapter 5 contains the conclusion.
While chapter 4 is very long, it is extremely thorough. Each of the fifteen sections contains information on secular trends (US evidence only), plausible mechanisms (evidence from the US and around the globe), observational studies (evidence from the US and around the globe). Surprisingly, some sections in this particular chapter had a dearth of evidence available. Also, although other sections in this chapter contained extensive information related to the development of obesity, there were many conflicting bodies of research, and it was sometimes difficult for the authors to draw a conclusion based on the available evidence.
Chapter 5 summarises the influences of life cycle on the development of obesity, and highlights the need for early prevention efforts, which the authors state should begin preconception. As excess adipose tissue development can occur very rapidly in childhood and as childhood obesity is known to track into adolescence and adulthood, the authors suggest that special consideration should be given to prevention of childhood obesity. On examination of all the evidence relating dietary factors to obesity, a consistent trend in the findings was observed by the authors in that ‘No single factor stood out as having an overwhelming influence on energy balance: rather a dietary pattern for obesity prevention emerged’. This dietary pattern took into consideration a variety of foods and dietary practices which consistently demonstrate negative associations with the development of obesity (e.g. breastfeeding, consuming adequate fibre and calcium, reducing fat intake, reducing soft-drink consumption, consuming breakfast) This section also highlights very clear areas which warrant future research. The authors acknowledge the latter point but they also practically state, that as obesity is such a pressing issue, action needs to be taken on evidence available rather than waiting for the results of decades of further study.
This is a well written, well thought-out piece of work and although not designed as an ‘easy-reading’ book, I feel it is an invaluable up-to-date reference document. Although this book has its main focus on the US population, I believe that the information contained is transferable to other industrialised countries. Some basic knowledge of nutrition and life sciences would be beneficial to the reader. Therefore, I would recommend that those studying obesity in the final year of their degree programme or in post-graduate study, those researching obesity or involved in the development and delivery of obesity prevention programmes would find this book a very timely, valuable resource.
