Foreword

Healthy eating is part and parcel to the effective management of diabetes, and registered dietitian nutritionists (RDN) need to play a major role. The American Diabetes Association Guide to Nutrition Therapy for Diabetes, edited by Alison Evert and Marion Franz, now in its third edition, is extremely evidence-based with large doses of experience and practicality. Although weight loss is important for the prevention of type 2 diabetes (T2D) in those at risk and in the management of T2D, and increasingly important in people with type 1 diabetes (T1D), initial steps should focus on the quality not quantity of the eating pattern. And recent data supports that there’s no need to worry about percentage of calories in the form of macronutrients; yet we all know the variable and time-dependent impact of type of carbohydrate on postingestion glycemic excursion and of type of fat (saturated/trans versus unsaturated) on low-density lipoprotein cholesterol (LDL-C).

You’ll notice the term “eating pattern” reverberating throughout this book. A description of certain foods as ‘good’ or ‘bad’ is no longer acceptable. Instead, focus should be placed on overall eating pattern. Evidence supports following an eating pattern that is enriched with fruits, vegetables, lean poultry, and fish, and one in which most of the carbohydrates consumed are complex rather than simple. When a person with any type of diabetes follows a weight-maintaining Mediterranean-style or DASH eating pattern, for example, there’s very little room for foods high in simple sugar or saturated or transfat to be included. Enjoying a rare steak once a month or ice cream or sorbet with a slice of birthday cake on rare occasions isn’t something our patients need to confess. Adjustments in glucose management for the expected glycemic excursion with ice cream and cake can easily be made with input from an RDN, certified diabetes educator (CDE), and/or health-care provider. We need to not only inform our patients about the importance of medical nutrition therapy but make eating a fun and enjoyable experience for them.

When weight reduction is needed, a caloric deficit of energy intake and expenditure is needed with adjustments in glucose-lowering medications anticipated as the weight-loss regimen is implemented and sustained. Although controlled trials examining the impact of lifestyle to achieve weight loss emphasize the importance of both reduced intake and increases in energy expenditure in the form of exercise, when people with diabetes are seen in the outpatient clinic I believe the early emphasis should be on adjusting energy intake (with implementation of a more active lifestyle once the period of weight loss is underway and maintenance is key). During active weight reduction almost every cardiometabolic variable changes for the better except high-density lipoprotein cholesterol (HDL-C), which decreases. But once weight is stabilized at a level 5–10% above baseline, HDL-C increases above baseline values.

The true strength of this third edition of American Diabetes Association Guide to Nutrition Therapy for Diabetes is the approach to the literature utilized by the authors. Herein the authors were asked to state the question(s) related to nutrition therapy in diabetes that they were attempting to answer upfront, and then examine and report back on each question’s study inclusion criteria. Although falling short of the rigorous process advocated by the Institute of Medicine (now the Health and Medicine Division of the National Academies of Medicine) for guidelines, the approach has convincingly substantiated the recommendations that follow. This edition is comprehensive, with chapters devoted to almost any conceivable medical nutrition therapy issue that arises in every type of diabetes and under a wide variety of circumstances: T1D and T2D (in all age ranges); how to integrate nutrition therapy with continuous glucose monitoring and insulin pump therapy; pregnancy and lactation; before, during, and after exercise; during sick days, hospitalization, and long-term care; comorbidities associated with diabetes including hyperlipidemia, hypertension, chronic kidney disease, eating disorders, celiac disease, cystic fibrosis, and diabetic gastropathy. Importantly, attention is also given to methods to engage individuals with limitations of literacy, and to the costs of and strategies to educate and implement nutrition therapy in communities.

Now, what about physicians? For several decades now I’ve taken an anecdotal and mostly nonscientific approach to evaluating the effect of a ‘3-minute lifestyle interview’ in all patients with or without diabetes in my clinic. This practice was the basis of my President’s Address at the American Heart Association Scientific Sessions in 2005 (Circulation 113:2657, 2006). In addition, I’m privileged to have Shannon Christen, RDN, CDE, who is experienced and well trained in nutrition therapy and diabetes education, working quite closely with me. This practice is based on a hypothesis that physicians in general dismiss lifestyle questioning— apart from alcohol, tobacco, and drug use—for a number of reasons including time, knowledge of nutrition therapy, and the inability to change a person’s behavior. Questions for people with diabetes differ little from those for people without diabetes. In terms of nutrition, these questions include: How many servings of fruits and vegetables do you eat daily? How many servings of whole grains daily? How many servings of fish each week? Do you read food labels? Are you concerned about saturated/trans fat and refined sugar or starch intake? And for those people with diabetes: How does carbohydrate in general and the type of carbohydrate affect your blood glucose levels and related glycemic management? Then, regarding physical activity, questions might include: Do you have a regular exercise program? Are there limitations to your ability to exercise? Do you wear a step counter? How many days per week do you work out? For how many minutes per day and how strenuous is the exercise (e.g., do you sweat?)? Not only is this information important for optimizing lifestyle management, but it provides a teaching moment, an opportunity for physicians to encourage healthful lifestyle changes for individuals with or without diabetes.

This new edition of the American Diabetes Association Guide to Nutrition Therapy for Diabetes, edited by Evert and Franz, should be a “must” for the entire diabetes management team, including physicians. A1C is our metric and drugs are easy to prescribe, but medical nutrition therapy is the basis of good diabetes management and when implemented has the potential to replace anywhere from one to three prescription drugs our patients are taking.

Robert Eckel, MD, is Professor of Medicine in the Division of Endocrinology, Metabolism, and Diabetes and Division of Cardiology and Professor of Physiology and Biophysics at the University of Colorado Denver Anschutz Medical Campus. He is a past President of the American Heart Association and is currently on the Board of Directors of the American Diabetes Association.