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i-a2e1dd9aba10ed79522bbfa16dbed276-Joe_Schwarcz2.jpgCALORIE COUNTS AREN’T TELLING THE FULL STORY
By Joe Schwarcz, Freelance
July 30, 2011

There are undoubtedly all sorts of terrorists out there hatching intricate plans aimed at destroying the western world. They needn’t bother. All they have to do is wait and westerners will eat themselves into oblivion. The average western diet, with the U.S. leading the pack, is atrocious. People are getting fatter and fatter. Obesity-related ailments such as heart disease, cancer and diabetes take a giant toll both in terms of tax dollars and human misery. Something needs to be done.

The standard answer is to try to educate people to eat less and exercise more.That of course is sound advice, at least as far as the laws of thermodynamics go. And rest assured that these laws will never be repealed.It is a fact that the only way to lose weight is to take in fewer calories than are expended.But counting calories is notoriously difficult. Besides the difficulty in estimating serving sizes, calorie counts on labels can be deceiving.

The calorie determination system formulated over 100 years ago by the American chemist Wilbur Olin Atwater is flawed. Atwater burned weighed samples of food in a “calorimeter” and measured the amount of energy released in the form of heat. After correcting the values for undigested food he isolated from feces, as well as for food metabolites in the urine, Atwater concluded that proteins and carbohydrates provide four calories per gram while fat provides some nine calories per gram. Alcohol weighed in at seven calories per gram and dietary fibre, which is mostly indigestible, furnished just two calories per gram. These are the values used today to calculate total calorie counts on labels.

But the fate of food in the body is not the same as in a calorimeter. Texture, for example, can make a difference. When rats are fed either soft pellets or hard pellets, they will put on more weight with the soft ones even if the calorie count is identical. It is also known that a significant percentage of coarse-ground flour is excreted while finely milled flour is almost completely digested, yet both would be calculated to have the same number of calories.Even cooking makes a difference. A well-done steak provides more available calories than a rare one. It may seem that these are insignificant differences, but small differences add up. Making an error of just 20 calories a day can add up to a gain of a kilogram over a year.

We need a better way of controlling our food intake than counting calories. And researchers at the Harvard School of Public Health may have put us on track by analyzing surveys filled out by 120,000 nurses, physicians, veterinarians and dentists over a period of about 20 years.Starting in the 1980s, these subjects answered questionnaires about their diet and weight, including specifics about the number of servings of various foods they consumed per day. Some fascinating revelations emerged from the huge amount of data collected.First of all, there was an average weight gain of about 17 pounds over 20 years.Of course people who exercised put on the fewest pounds.Remember, these were educated people who presumably knew something about nutrition, yet pounds still snuck on, roughly at a rate of a pound a year.

The Harvard researchers wondered if there were specific foods that were more likely to cause weight gain.As one might expect, over the 20 years of the study, there were changes in eating habits with some subjects eating more of certain foods, less of others. Statistical analysis was able to tease out the effects of these changes on weight.French fries emerged as the No. 1 villain. People who increased their intake were most likely to put on weight. Other types of potatoes, especially chips, also were linked to weight gain, although not as much. This may seem obvious because the fries contain more fat, yet adding an extra serving of nuts a day actually results in the loss of about a fifth of a pound over a year, despite the nuts being rich in fat.So weight control is more complex than just counting calories. Nuts apparently have a greater satiety value and keep people from feeling hungry for a longer time than the fries.

As one would guess, eating more fruits, vegetables and whole grains was associated with weight loss. Also as expected, refined grains and especially sugar-sweetened beverages were associated with weight gain. It was also no great surprise that red meat and processed meats put on the pounds.But there was a surprise with dairy products. Whether whole fat or low fat, they didn’t have much of an effect.

The biggest shock was yogurt. People who ate a serving a day were likely to see a weight loss of a third of a pound over a year. That would seem to mesh with some recent research showing that the types of bacteria present in the digestive tract have an effect on the amount of energy extracted from food and hence on the tendency to put on weight.

What all this means is there are foods to stay away from and foods to include in the diet.Minimize red meat and eat plenty of fruits, vegetables, nuts and yogurt.Stay away from fries, chips, and refined cereals. Sweetened soda pop is the real ogre. The average American consumes half a litre a day. That’s about 200 unnecessary calories and cutting them out will lead to a weight loss, or non-gain of some two pounds a month!

But how do you get people to cut their caloric intake? It would seem that if people were more aware of the calorie content of foods they would be more careful about what they consume. That’s why in 2008 New York City passed a law requiring fast food restaurants that had at least fifteen franchises across the country to post calorie content on their menus. Now, three years later, we can ask the question whether such programs are successful.A recent paper published in the British Medical Journal indicates that such calorie information can be useful in terms of cutting intake as long as consumers pay attention to what is posted. But surveys show that only 15% of customers report paying attention to the information. Indeed after the program went into effect register receipts showed no overall change in calories purchased for lunch. Customers who paid attention to calorie counts reduced their purchases by about 106 calories. That’s meaningful. Researchers calculate that saving that many calories a day could translate to 150,000 fewer cases of obesity in New York City alone.

Unfortunately advice about calorie counting has not stemmed the rising tide of obesity. Neither have the numerous diet books that flood the market made a significant impact. In many cases people find the regimens too complex to follow. Maybe what we need is a simplification of decision making. How about this? Forget sugar-sweetened soft drinks and limit fries to once a month. (They just taste too good to cut them out completely.) These two simple measures are likely to reduce obesity and associated health costs.Please spare me the argument about all foods being all right as long as they are eaten in moderation. In America, “moderation” seems to be a foreign concept.

Joe Schwarcz is the director of McGill University’s Office for Science and Society (OSS.McGill.ca). e can be heard every Sunday rom 3-4 p.m. on CJAD radio. joe.schwarcz@mcgill.ca

© Copyright (c) The Montreal Gazette

What do you think of calorie counting as a means to weight loss?

Read more about Dr. Schwarcz here.

Comments

  1. #1 hibob
    August 5, 2011

    No comments on whether it’s the foods themselves or whether people eating yogurt are much more likely to be consciously attempting to lose weight (and perhaps counting calories), whereas the people eating more fries and chips might not be? Id est, it’s the attempt to lose weight causes the increase in yogurt consumption and the drop in potato consumption. I couldn’t find any mention of controlling for this in the (unfirewalled portion) of the Harvard study, but the cited BMJ article would certainly support it.

    Also, a link to the Harvard study:
    http://www.nejm.org/doi/full/10.1056/NEJMoa1014296?query=TOC#t=articleTop

    A pet peeve of mine in science journalism is not even bothering to mention at least one way to find the original study. A link or the paper’s title is ideal, but the name of the journal and the name of an author or two is a good start. If there’s room to mention the journalist three times and link to him four times, there’s room for the names of the scientists whose work he’s reporting on.

  2. #2 Art
    August 5, 2011

    Yogurt, who knew?

    Pet peeves of diet include the emphasis on weight, 200 pounds and muscular is clearly better than 200 pounds and all lard, and an avoidance of the fact that if you don’t exercise counting calories is largely futile. It isn’t a problem that you don’t much mention exercise, it is outside the scope of your piece, but it is pretty easy to read scores of diet books without having the need for exercise pounded home. That’s not so good.

    It is interesting to see people come into programs that largely ignore diet but emphasize exercise, military boot camps come to mind, and see people lose weight and get healthier in just a few weeks. Work them hard 0500 to 2100 and for a lot of people it doesn’t really matter what, or how much, they eat. That’s extreme but even a limited investment of twenty minutes a day of solid exercise can make a difference.

  3. #3 starskeptic
    August 6, 2011

    the fact that if you don’t exercise counting calories is largely futile

    not true at all – keeping track of your intake is even more important if you’re not exercising – also very useful if one is temporarily unable to due to illness or injury…

  4. #4 Kandy Collins
    August 6, 2011

    Thanks for your insightful comments and for including the link to the Harvard study.

  5. #5 Kandy Collins
    August 6, 2011

    Thank you for writing in and for your thoughtful comments.

  6. #6 Kandy Collins
    August 6, 2011

    We appreciate your input. Thanks for writing in.

  7. #7 Betzi
    August 7, 2011

    As for the yogurt, I agree that the benefit probably comes from the fact that people who eat it are probably consciously trying to lose weight. I don’t think there is enough scientific evidence out there to suggest that the bacteria in yogurt does anything in terms of making people lose weight. People eating yogurt are probably making a healthier choice. Instead of ice cream, brownie, or other dessert, they eat the yogurt which satisfies some of the sweet craving with less calories.

    I also have a problem with thinking that red meat leads to weight gain. This seems to be what the numbers show, but I’ll bet it has to do with red meat (mainly hamburgers) being in line with the consumption of french fries (which is the real culprit here). Eating red meat at home with a side of brown rice and broccoli will probably not lead to weight gain. Eating fast-food hamburgers on a white-bread bun with a zillion french fries will.

    The numbers do not tease out these finer points of human behavior.

  8. #8 Kandy Collins
    August 7, 2011

    Thanks for following our blog and for your insightful comments.