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The New York Times front page today has a report of a long-term study at NIH of severe calorie restriction in Rhesus monkeys. It found that calorie restriction did not extend the monkeys’ lifespan.
I’m not at all surprised. My co-author and I reviewed the literature on calorie restriction for a chapter in our book, Why Calories Count.
The new study makes news because it contradicts a study done in Wisconsin showing that severe calorie restriction extends life. Severe means 25% to 30% fewer calories per day that are needed to maintain normal body weight. I’d call this a starvation diet.
An editorial accompanying the report of the study in Nature attributes the difference between the results of this NIH trial and the Wisconsin study to a difference in dietary composition, suggesting that calories differ in their effects.
Not necessarily. The Wisconsin study allowed the control monkeys to eat a lot of junk food and they were fatter than normal. The NIH study restricted calorie intake in its control monkeys so they maintained normal weight and were healthier. This is the simplest explanation of the difference.
Studies in rats, mice, and many other animals show that calorie restriction extends life.
But what about primates?
Starvation can hardly be good for health. It causes weight loss, of course, but also a host of physiological and psychological problems. These were extensively documented in humans during World War II in Ancel Keys’ Starvation studies.
The relationship between BMI and human longevity has been examined in several recent studies, all of which show similar results: Longevity is best associated with BMIs in the range considered normal or slightly overweight. Above that range—but also below it—mortality increases.
Being underweight is associated with higher mortality.
A Canadian study provides this example:
And one from the National Cancer Institute provides another:
The bottom line? Eat a healthy diet and balance calories to maintain a healthy weight within that range.
NYU did an interview for the Steinhardt School’s website:
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.
And for another view: My co-author, Dr. Malden Nesheim, did a Q and A on the book with Diets in Review.
USA Today’s Nanci Hellmich interviewed me and my co-author, Malden Nesheim, about Why Calories Count:
When it comes to calories, some people count them, others are confused by them and some just ignore them. Marion Nestle, a nutrition professor at New York University, and Malden Nesheim, professor emeritus of nutritional sciences at Cornell University, look at the topic in Why Calories Count: From Science to Politics. USA TODAY’s Nanci Hellmich talked to them about the new book.
Q: Why do women in general need fewer calories than men?
A: Women are smaller and generally have a higher body fat content than men. Fatty tissue needs less energy to maintain than does muscle mass. Pregnancy and breast-feeding increase women’s calorie needs.
Q: Why do some people have an easier time maintaining a healthy weight than others? How many calories are used by basal metabolism?
A: Genetics has plenty to do with body weight and some people seem to be able to eat vast amounts of food without gaining weight. About two-thirds the calories we need go for basal metabolism — the amount of energy needed to support basic body functions like breathing, blood circulation, kidney function, etc. The rest primarily supports physical activity. So if you want to lose weight, you have to eat less or move a lot more.
Q: Why does energy expenditure decline as much as 20% by age 50 and 30% by age 71 and older?
A: This, in our opinion, is one of life’s great tragedies. Basal metabolism drops with age and so does muscle mass. Lots of people are less physically active when they get older. Staying active does lots of good things for health and one of them is compensating for the decline in calorie needs.
Q: Are all calories created equal when it comes to weight loss?
A: If you lock people in a metabolic ward and feed them the same number of calories in reduced-calorie diets that vary in fat and carbohydrates (all measured), you can show that they lose weight at the same rate regardless of diet composition. The number of calories determines how fast they lose, nothing else.
In the real world, some people lose weight faster on low-carbohydrate, high-fat diets, such as the Atkins diet, especially at the beginning when they excrete so much water. Some people find that low-carbohydrate diets make it easier to reduce calories and stay satiated. And it’s always a good idea to cut back on desserts and sodas.
Q: Do excess calories make some people gain weight faster than others?
A: Here’s where genetics comes in. In controlled studies of overfeeding, everyone gains weight when they eat more calories than they expend, but at different rates. Some people can overeat and gain only a little weight — growing teenage boys are a good example. They may spontaneously increase their physical activity to burn off excess calories. Other people easily store more of the extra calories as fat.
Q: What is your best advice to people who want to lose weight?
A. Our mantra is: Get organized; eat less; eat better; move more; get political. By get political, we mean work to change the food environment to one that makes it easier to eat healthfully: Support labeling laws and nutrition education; stop advertising to children; support agricultural policies that encourage consumption of fruits and vegetables, local food systems, and environments that encourage physical activity.
Q: What do calories have to do with politics?
A: How much food people eat — and whether they are malnourished or overweight — is affected by income, education, and, therefore, the political system. Many companies and vested-interest groups have a stake in how calories are marketed, perceived, labeled, and promoted, not least because eating less is bad for business.
Efforts to do something about obesity in adults and children focus on eating less or on eating better, meaning 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. 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.
Jane Brody, Personal Health, March 20: Calories are everywhere yet hard to track
The human body has a very complex and redundant system to make sure the brain gets the sugar calories it needs to function, Dr. Nestle and Dr. Nesheim explain in their book. At least 100 different hormones, enzymes and other chemicals — with more likely to be discovered — act to regulate appetite and to assure that people eat enough to maintain brain function.
But it is these very systems that go into overdrive during starvation (translation: a reduced-calorie diet), making it so difficult for people to lose weight.
Mark Bittman, Opinionator, March 21: Is a calorie a calorie?
Ultimately, the calorie is political: marketing affects instinct, and Nestle and Nesheim really shine in their analysis in this realm. (Their slogan: “Get organized. Eat less. Eat better. Move more. Get political.”)
When I asked Nestle what she would do, given that people in the United States were obviously eating too many calories and that the resulting excess weight was costing all of us life years and money, she answered quickly: “We need a farm bill that’s designed from top to bottom to support healthier diets, one that supports growing fruits and vegetables and making them cheaper.
We need to fix school lunches so they’re based on fresh foods, and fix food assistance programs so people have greater access to healthier foods.”
NATURE, March 14, 2012, Review
(Books in Brief review (scroll down to the second one)
Why Calories Count: From Science to Politics
Marion Nestle and Malden Nesheim University of California Press 304 pp. $19.95 (2012)
Obesity has gone global — as has misinformation about nutrition and food. Nutrition scientists Marion Nestle and Malden Nesheim unscramble the confusion with a serving of science.
They reveal how calories — those potent but ill-understood measures of heat energy — are really counted, why we need them, how we use them, how many we actually need and why it all sometimes goes so wrong.
From The Scientist: Magazine of the Life Sciences, February 2012.
by Marion Nestle and Malden Nesheim
University of California Press, April 2012
Nutritional science guru Marion Nestle’s new book, Why Calories Count, seeks to crack open the inscrutable nature of the calorie. Think of the book, cowritten with Cornell University nutritionist and biochemist Malden Nesheim, as a diner’s elemental guide to eating. Nestle and Nesheim deconstruct the calorie—the bane of many a belly in the developed and developing worlds—to its barest components as a humble unit of work or heat before reassembling it and discussing its implications for disease, obesity, politics, and modern marketing.
From the strict chemical definition of a calorie to the 25-year quest by the Center for Science in the Public Interest to require nutritional labels, including calories, on alcoholic beverages, Why Calories Count weaves scientific and social tales into a rich portrait of the American diet and the laws that have shaped it.
By thoroughly burrowing into the meaning and impacts of calories, the authors intend to bestow a more relaxed yet active state of mind upon the reader. “Get organized. Eat less. Move more. Get political,” they suggest. Sounds like the most succinct diet book ever written.