Currently browsing posts about: Calories

My Tuesday question from student readers of NYU’s Washington Square News:

Question: How can we determine our individual caloric, vitamin, carbohydrates, fats and other intake requirements per day based on our own individual weight, height and lifestyle?

Answer: You can’t. You will have to be satisfied with estimates based on measurements performed years ago on a small number of study subjects.

We require calories and nutrients — 40 to 50 separate substances that our bodies cannot make, we must get from food. Because these interact, studying one at a time gives results that may well be misleading.

Early nutrition scientists got “volunteers”— in quotes because study subjects often were prisoners — to consume diets depleted in vitamin C, for example. They waited until the subjects began to develop scurvy, a sign of vitamin C deficiency. Then they fed the subjects the smallest amount of vitamin C that would eliminate symptoms.

Because individuals vary in nutrient requirements, scientists used this data to estimate the range of nutrient intake that would meet the needs of practically everyone.

The Institute of Medicine compiles such data into Dietary Reference Intakes and presents the estimates by sex and age group. You can look up your requirements in DRI tables. DRIs account for the needs of 98 percent of the population. If your requirements are average, you will need less.

Few American adults show signs of nutrient deficiencies, but if you are worried about your own intake of nutrients, you can take a multivitamin supplement. Note, however, that we have no evidence to show supplements make healthy people healthier.

You can estimate calories by looking up everything you eat or drink in food composition tables, but it is easier to weigh yourself at regular intervals. If you are gaining weight, you are eating too many calories for your activity level.

With nutrition, it’s best to get comfortable with estimates and probabilities.

Fortunately, eating a healthy diet takes care of nutrients without your having to give them a thought. Eat your veggies!

A version of this article appeared in the Tuesday, May 1 print edition. Marion Nestle is a contributing columnist. Email her questions at dining@nyunews.com.

On Tuesdays, I answer questions about nutrition for NYU’s student newspaper, the Washington Square News.  Yesterday’s was about when calories count.

Question: With finals approaching ,many students will be staying up very late. Is the time of day important in relation to when you are consuming most of your calories? What are some good late-night, study snack options for students?

NYU did an interview for the Steinhardt School’s website:

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.

My Tuesday Q and A for NYU’s Washington Square News:

From The Scientist: Magazine of the Life Sciences, February 2012.

Why Calories Count: From Science to Politics

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.

A new diet study just out from the American Journal of Clinical Nutrition went to a lot of trouble to prove the obvious.  When it comes to weight loss, how much you eat matters more than the proportion of fat, carbohydrate, and protein in your foods.

Researchers at the Pennington Biomedical Research Center got volunteers to eat diets that were supposed to differ in proportions of fat (40% vs 20%), carbohydrates (35% vs. 65%), and protein (25% vs. 15%).

The results of the study are consistent with the findings from many previous studies:

• The major predictor for weight loss was adherence to the diet.
• People on all of the diets lost weight by six months, but regained some of it by two years.
• The study had a high drop-out rate (hence the importance of adherence).
• It was hard for people to stick to the diets, especially those at the extremes of one dietary component or another.

In my book with Malden Nesheim coming out on April 1, Why Calories Count: From Science to Politics, we review the previous studies of whether what you eat matters more to weight loss than how much you eat.

Some people find it easier to stick to diets that are higher in protein and fat.  I’m guessing that proponents of low-carbohydrate diets will argue that none of the diets in this particular study was really low in carbohydrate.

But studies show that people have a hard time adhering to diets that are very low in carbohydrate.  The low range in this study—35%—is at the lower end of acceptability for many people.

The bottom line: all diets work if you stick to them.

My monthly Food Matters (first Sunday) column in the San Francisco Chronicle takes out a crystal ball…

Q: What’s on the food politics agenda for 2012? Can we expect anything good to happen?

A: By “good,” I assume you mean actions that make our food system safer and healthier for consumers, farmers, farm workers and the planet.

Ordinarily, I am optimistic about such things. This year? Not so much. The crystal ball is cloudy, but seems to suggest:

Political leaders will avoid or postpone taking action on food issues that threaten corporate interests. Sometimes Congress acts in favor of public health, but 2012 is an election year. Expect calls for corporate freedom to take precedence over those for responsible regulations. Maybe next year.

Something will happen on the farm bill, but what? Last fall’s secret draft bill included at least some support for producing and marketing fruits and vegetables, and only minimal cuts to SNAP (food stamps). Once that process failed, Congress must now adopt that draft, start over from scratch or postpone the whole mess until after the election.

SNAP participation will increase, but so will pressure to cut benefits. With the economy depressed, wages low and unemployment high, demands on SNAP keep rising. In 2011, SNAP benefits cost $72 billion, by far the largest farm bill expenditure and a tempting target for budget cutters. While some advocates will be struggling to keep the program’s benefits intact, others will try to transform SNAP so it promotes purchases of more healthful foods. Both groups should expect strong opposition.

Childhood obesity will be the flash point for fights about limits on food marketing. The Lancet recently summarized the state of the science on successful obesity interventions: taxes on unhealthy foods and beverages, restrictions on marketing such items, traffic-light front-of-package food labels, and programs to discourage consumption of sugar-sweetened drinks and television viewing. Expect the food industry to continue to get Congress to block such measures, as it did with U.S. Department of Agriculture school nutrition standards (hence: pizza counts as a vegetable).

The Federal Trade Commission will postpone release of nutrition standards for marketing to children. Although Congress asked for such standards in the first place – and the standards are entirely voluntary – it just inserted a section in the appropriations bill requiring a cost-benefit analysis before the FTC can release them. Why does the food industry care about voluntary restrictions? Because they might work (see previous prediction).

The Food and Drug Administration will delay issuing front-of-package labeling guidelines as long as it can. The FDA asked the Institute of Medicine for advice about such labels. The institute recommended labels listing only calories, saturated and trans fat, sodium and sugars – all nutrients to avoid. Although the institute did not mention traffic-light labels, it did recommend check marks or stars, which come close. The food industry much prefers its own method, Facts Up Front, which emphasizes “good-for-you” nutrients. It is already using this system. Will the FDA try to turn the institute recommendations into regulations? Maybe later.

The FDA will (still) be playing catch-up on food safety. The FDA got through the 2011 appropriations process with an increase of about $50 million for its inspection needs. This is better than nothing but nowhere near what it needs to carry out its food safety mandates. The FDA currently inspects less than 2 percent of imported food shipments and 5 percent of domestic production facilities. The overwhelming nature of the task requires FDA to set priorities. Small producers think these priorities are misplaced. Is the FDA going after them because they are easier targets than industrial producers whose products have been responsible for some of the more deadly outbreaks? Time will tell.

On the bright side, the food movement will gather even more momentum. While the food industry digs in to fight public health regulations, the food movement will continue to attract support from those willing to promote a healthier and more sustainable food system. Watch for more young people going into farming (see Chronicle staff writer Amanda Gold’s Dec. 25 article) and more farmers’ markets, farm-to-school programs, school meal initiatives, and grassroots community efforts to implement food programs and legislate local reforms. There is plenty of hope for the future in local efforts to improve school meals, reduce childhood obesity, and make healthier food more available and affordable for all.

And on a personal note: In April, University of California Press will publish my co-authored book, “Why Calories Count: From Science to Politics.” I’m hoping it will inspire more thinking and action on how we can change our food system to one that is better for people and the planet.

Happy new year!