Skip to comments.Have We Been Miscounting Calories?
Posted on 02/27/2013 2:42:55 PM PST by neverdem
BOSTON—When it comes to weight loss, a calorie is a calorie is a calorie. That's been the mantra of nutritionists, dietitians, and food regulators in the United States and Europe for more than a century. But when it comes to comparing raw food with cooked food, or beans with breakfast cereals, that thinking may be incorrect. That was the consensus of a panel of researchers who listed the many ways that the math doesn't always add up correctly on food labels here on Monday at the annual meeting of AAAS (which publishes ScienceNOW). "Our current system for assessing calories is surely wrong," said evolutionary biologist Richard Wrangham of Harvard University, the co-organizer of the panel.
In a wide-ranging discussion of how food is digested in everything from humans to rats to pythons, the panel reviewed a new spate of studies showing that foods are processed differently as they move from our gullet to our guts and beyond. They agreed that net caloric counts for many foods are flawed because they don't take into account the energy used to digest food; the bite that oral and gut bacteria take out of various foods; or the properties of different foods themselves that speed up or slow down their journey through the intestines, such as whether they are cooked or resistant to digestion.
The process used to estimate calories for food was developed at the turn of the 19th to 20th century by Wilbur Atwater. It was a simple system of calculating four calories for each gram of protein, nine calories for each gram of fat, and four calories for each gram of carbohydrate (modified later by others to add two calories for a gram of fiber). Although it has been useful for approximating the energetic costs of metabolizing many foods, its shortcomings have been known for decades—and some nations, such as Australia, have dropped the system because it is "inaccurate and impractical," said panelist Geoffrey Livesey, a nutritional biochemist and director of Independent Nutrition Logic Ltd. in Wymondham, U.K..
One key area where the system is inaccurate, Wrangham reported, is in estimating the calories for cooked food. Cooked items are often listed as having fewer calories than raw items, yet the process of cooking meat gelatinizes the collagen protein in meat, making it easier to chew and digest—so cooked meat has more calories than raw. Heat also denatures the proteins in vegetables such as sweet potatoes, said Harvard University evolutionary biologist Rachel Carmody, a postdoc who studies the energetics of digestion and organizer of the session.
The way foods are processed can also make them easier to digest. Take "resistant" starch in cereal kernels, such as barley grain, or beans, which take a long time to digest. But grind the same cereals into flour or process it into breakfast cereal or instant oatmeal, and it becomes easy to digest, said biochemist nutritionist Klaus Englyst of Englyst Carbohydrates Ltd., a carbohydrate chemistry firm in Southampton, U.K. This is why "bread is more rapidly digested; beans more slowly," he said.
New studies also are finding that bacteria in the gut respond differently to processed foods and cooked foods. Carmody reported that she and Peter Turnbaugh of Harvard University are finding "key differences in the type of bacterial communities" in the guts of mice, depending on whether they were fed chow or cooked meat. "The food you eat has an enormous impact on the gut bacteria," and, in turn, on the energetics of digestion, Carmody said.
Why does all of this matter? Because we're in the midst of an obesity epidemic and counting calories has been misleading, said David Ludwig, a pediatric endocrinologist at Children's Hospital Boston and Harvard Medical School. How the body processes different foods in different ways matters. "The quality of calories is as important as the quantity of calories." While others not on the panel welcome applying "the best science" to the problem of weight loss, they also provide a word of caution about getting too worried about precise calorie counts. "You can put a ton of effort into getting more accurate calorie counts," says nutrition scientist Christopher Gardner of Stanford University in Palo Alto, California. "But why are you doing this? Will it make a real difference? If you want to lose weight, you still have to cut back on calories." A few calories here and there may not matter to most people. But to the panel members, every little bit counts.
*Correction, 20 February: Cooked items are often listed as having fewer calories than raw items, not more calories as originally reported.
Cannot count the doctor who assured my overweight self that ‘calories in and calories out’ was a rule of science and if I wasn’t losing weight it was because I was eating too much and not exercising enough.
Everyone processes different items differently and cannot be cookie cutter to everyone.
Much of science is like the weather, it is what ever it is today.
Anybody who has gone low glycemic index knows this. But hey, let’s keep federally mandating that cookies and soda have visible calorie info on their packages. It’s fer the childrun.
Not true at all.
Losing weight is very simple - 3500 calories = a lbs of fat.
A daily deficit of 500 calories either through diet or exercise will yield one lbs weight loss per week in almost all people.
The biggest problem is that most people grossly underestimate how much they are eating and overestimate how many calories they are burning through physical activity.
Starvation does not work either since the bodies metabolism will shut down and you will burn muscle and not fat which is a disaster for the body.
Throw away those five agribusiness-sponsored fallacies and you are 90% of the way to solving the obesity epidemic - no matter how many garbanzo beans you eat.
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I cut out beer, bread, pasta, and most starches back in August and Im down 35lbs.
I exercise like an animal now that Obamacare is coming and eat steak eggs, salads, cheese, red wine, vodka, and the weight stays off.
I’ve been having too many intimate dinners for two.....with just me showing up.
apparently if these age/weight/height/active or sedentary things are correct I can lose weight by eating as much as 2,300 calories per day
if I lay off bread and soda I could lose weight
but I love those things
No carbs for me either during the week....just lean protein and veggies. I save the carbs for my vino on the weekends.
Real science is always a work in progress. There are legions of dietitians doing worthless calorie counts, and others making faulty estimates for the National Health and Nutrition Examination Surveys.
We know that, but knowing that is a part of the past, thinking that is dying out.
I lost 37 pounds a few years ago by counting calories. I counted the calories I burned working out (just trusted the digital display on the elliptical machine at the gym) and counted the calories I consumed using the info on the packages or checking on-line. It worked like a charm for me. Now, I do know a few people who do count every calorie just like I did and they still can't lose weight. They have some kind of issue with their metabolism, apparently. But, you're right. For most people that simple formula, if followed carefully, will work.
Several twists and turns to this. Recently it was discovered that if you eat just raw foods, you have to eat much more, and will still likely suffer some degree of malnutrition after a while.
Cooking radically increases food nutritional value, to the point that when people innovated cooking, within a few generations it likely resulted in an evolutionary leap.
It was also recently noted that while typically, an adult has about 30-40 primary types of gut bacteria that take up most of the space, people who are severely obese have just one genus of bacteria, enterobacter, occupying a third of the space in the gut. And enterobacter release a waste product that makes people gain weight, even independent of the bacteria.
Those who were put on an anti-enterobacter diet dropped about 1/3rd of their excess weight with no exercise at all.
It takes about one month of effort to change the colony of gut flora, but that may be the optimal first step to weight loss.
I got deployed to Kuwait while in the Air National Guard for four months 2007-2008. My eating habits hardly changed except I ate a bigger breakfast on average. No alcohol, walking 15 minutes to and from work, and running (airborne shuffle, I’m old) twice a week for 30 minutes average. I lost 24 pounds off my beginning 190 pound self.
Low glycemic and/or parts of Atkins works. The Mediterranean diet works through healthy fats, complex carbos, and lots of greens and veggies.
It’s not rocket science.
Don’t eat hydrogynated fats. Stick to olive oil, peanut oil, or grapeseed oil.
Don’t use hydrogynated vegetable shortening. Instead use homemade lard. Yes I just said lard. Non-hydrogynated lard is lower in the bad fats that cause cholesterol.
Don’t use margarine, it’s hydrogynated vegetable oils. Use real butter.
Don’t consume high fructose corn syrup. In fact, don’t drink sugary drinks period. Drink lots of water, one (1!) glass of red wine a night, or one hard alcohol drink a night without a sweet mixer.
Eat salad and eat vegatables.
Eat fresh fruit.
Take a good long walk every day.
You do those things and you won’t be obese unless your portion sizes are astronomical.
<The biggest problem is that most people grossly underestimate how much they are eating and overestimate how many calories they are burning through physical activity.
There is a British show on YouTube called ‘Secret Eaters.’ It places cameras in the homes of people who swear they don’t eat ‘that much’ and don’t understand why they can’t lose weight.
What they don’t tell the families is that they send private detectives after them and film and buy all the same stuff the family members buy or have at work (like left over donuts in the office kitchen).
People forget that they stopped for food on the way home, that they ate after going to the gym, or that they nibbled the whole time they were making dinner. It was fascinating.
One thing about the Brits, they sure like to drink. Many of the people would lose weight instantly if they cut out the constant drinking - and because they drink with their meals, lunch and dinner, it is easy to lose track of how much one is drinking. It’s worth a watch.
This isn’t really news. Many people have already heard that celery is actually net negative calories, because the act of eating it takes more calories than the food contains. Labels on packaging aren’t “net” calories. The amount of calories it takes to digest a particular food would vary from person to person, so it could never be represented on packaging.
But like the study says at the end, the amount of calories that consuming the food takes or doesn’t take is going to be negligible. It’s not going to be a significant number that would swing your results noticeably in either direction. I would expect just a little bit of real exercise would easily dwarf whatever calories were burned by simply consuming the food.
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