Marion Nestle On Why Calories Matter and Her Latest Book

Steinhardt’s own and one of the nation’s most renowned nutritionists, Marion Nestle, opens up about her latest book, Why Calories Count: From Science to Politics. Next Tuesday April 10, Nestle will be speaking at Fales Library’s “Critical Topics in Food Series,” focusing on the calorie: what it is, what it means, and why we count them. Below is a sneak peak into the food advocate’s newest work and why we should care about calories.

Why did you write this book?

Calories are critical to the most important public health, social, and economic issues facing the world today. About a billion people in the world do not take in enough calories to maintain health and are hungry and malnourished and another billion or so take in so many that they are overweight or obese and have higher risks for chronic disease and disability. The food industry takes in more than a trillion dollars a year in the United States alone. The U.S. diet industry is worth about $60 billion a year. The public is demonstrably confused about the meaning of calories and their relationship to food intake and weight loss. We thought it would be useful to write a book that provided accessible information about calories in all of their dimensions—scientific, health, and political.

What is a calorie?

Calories measure energy to keep bodies warm, power essential body functions, move muscles, or get stored as fat.

Why are calories a problem?

You can’t see, taste, or smell them. The only way you can recognize them is by their effects on your waistline or on a scale. They are not easy to count accurately and the best way to measure them is to weigh yourself regularly.

What are some of the themes of the book?

If you want to understand calories, you need to know the difference between calories measured and estimated. Most studies of diet, health, and calorie balance depend on self reports of dietary intake and physical activity or educated guesses about the number of calories involved. Most diet studies rely on estimates. When it comes to anything about calories in food or in the body, you have to get used to working with imprecise numbers. That is why it works better to eat smaller portions than to try to count calories in food. Even small differences in the weight of food will throw calorie estimations off.

Politics? What’s political about calories?

As with everything else having to do with food and nutrition, many groups have a stake in how calories are marketed, perceived, labeled, and promoted. As we’ve already said, eating fewer calories is bad for business. Efforts to do something about obesity in adults and children focus on eating less or on eating better, meaning eating more fruits, vegetables, and grains but consuming less of sodas, fast food, snacks, and other highly profitable items. Such matters as soda taxes, listing calories on food labels or menu boards, or campaigns to promote smaller portions are all political responses to concerns about calorie consumption. Here’s one example: for years, consumer groups have pushed for calorie and nutrition labeling on alcoholic beverages, but the Treasury Department (not the FDA) regulates such things and responds to the wishes of the industry.

What are the most important conclusions of the book?

If you want to eat well and maintain a healthy weight in today’s food environment, we advise: First, get organized; get motivated, monitor your weight regularly, join a weight loss group. Then eat less, move more, eat better and get political; work to change the food environment to one that makes it easier to eat healthfully, support labeling laws, nutrition education, controlling advertising to children, agricultural policies that encourage consumption of fruits and vegetables and local food systems, and environments that encourage physical activity.