Calorie counting based on a flawed, obsolete science, experts say

For Simon Leo Brown Y annabelle quince

Calorie counting has been the foundation of weight loss programs for more than a century.

It’s still a popular way to approach weight loss, whether it’s staying under a certain calorie limit on fasting days or using an app to calculate “calories in” and “calories out.”

But many leading experts are now calling for that to change.

They say counting calories is based on faulty and outdated science.

And they say our calorie obsession has actually made us fat.

calorie confusion

The calorie story is “complicated,” said Allison Marsh, a historian at the University of South Carolina.

“The term calorie comes up on different continents at different times with different meanings,” he tells ABC RN’s Rear Vision.

The calorie began life as a unit of stored heat.

French physicist Nicolas Clément used the term in the 1820s while lecturing on the efficiency of steam engines.

He defined the calorie as the heat required to raise the temperature of one kilogram of water one degree Celsius.

However, this was not the only definition, as others defined a calorie as the heat required to heat a single gram of water by one degree Celsius, a Clement-sized unit of 1000.

In 1879, the French chemist and politician Marcellin Berthelot distinguished the two units by designating the smaller one as the Calorie, with a lowercase c, and the larger one as the uppercase Calorie.

“Of course,” Marsh said, “this leads to an enormous amount of confusion.”

Adding to this confusion, the calorie is not the standard unit of energy in the International System of Units, that is the joule (a kilojoule is 1000 joules).

Potential energy

Part of the reason for the continued use of the calorie, especially in the US, was due to an 1887 article by chemist Wilbur Atwater, titled The Potential Energy of Food, published in the popular monthly magazine Century magazine.

Instead of trying to measure the fuel energy of a steam engine, Atwater was trying to measure the metabolic rate of the human body.

“I was really interested in how the body processes energy,” said Dr. Marsh.

He dedicated himself to measuring the potential energy of different types of food.

But, unlike some previous efforts to do this, he didn’t just measure the food once.

Atwater considered how much of the food we eat is actually absorbed into the body. He understood what Cambridge University obesity researcher Giles Yeo calls the “sweet corn scenario.”

“You eat corn on the cob, and then the next day you look in the bathroom and you clearly haven’t absorbed all the sweet corn,” Dr. Yeo said.

Atwater measured the calories in many different foods. He then fed these foods to human subjects, waited for them to digest the food, and measured their droppings.

He subtracted the calories in the poop from the calories in the food to arrive at the total number of calories absorbed.

He used these calculations to devise a system for determining the caloric content of food, for example, nine calories per gram of fat and four calories per gram of carbohydrate or protein.

“These numbers, these Atwater factors as they are still called, are the basis for all the calorie counts we see on every food package around the world today,” Dr. Yeo said.

calorie counting

Obesity was not an urgent public health problem in the 19th century, and experts were more interested in combating malnutrition.

But in the 20th century, weight loss became a priority, especially for women seeking the “ideal” body shapes portrayed in magazines and on the big screen.

In 1918, Dr. Lulu Hunt Peters published her best-selling diet book Food and Health: With Key to Calories.

The book was based on her syndicated newspaper column in which she documented her weight loss journey.

He calculated the calorie content of various foods in his diet and counted how many calories he was consuming.

“He started trying to cut calories to lose weight and was successful,” said Dr. Yeo.

Dr. Yeo said that Peters’ book “weaponized” the calorie.

“She was the mother of calorie counting and calories in weight loss.”

the halo effect

In the years after World War II, US public health authorities became increasingly concerned about the rising rate of heart disease, which was associated with weight gain.

In an attempt to slim down the population, the concept of the calorie was popularized. “It was something that people thought they could control,” said London-based freelance journalist Peter Wilson, who wrote The death of the calorie in The Economist’magazine s 1843.

Fat became the focus of government policy because a gram of fat contained more calories than a gram of carbohydrates or protein, he said.

Politics also came into play.

“The sugar lobby outsmarted, lobbied, and paid the fat lobby, and [they] it has pointed the finger of blame at fat as a cause of obesity, diabetes and the increased incidence of heart attacks,” he said.

“So in the 1970s and early 1980s, the American government basically said that fat is the enemy.”

The food industry loved this, Wilson said, because they could make highly processed foods that claimed to be healthy because they were low in fat.

The products were profitable and had a long shelf life, because the fat was replaced by sugar, starch and salt, Wilson said.

One example of such a product, said University of Sydney historian Chin Jou, was SnackWell’s, a much-hyped brand of low-fat biscuits.

“The idea was that Americans could have both: that they could enjoy delicious foods and that those foods could be low in fat,” said Dr. Jou.

The cookies tasted great, she said, because they were “full of sugar.” However, because they were low in fat, they were lower in calories than other cookies.

Worse yet, these foods encouraged overeating.

“The problem was that these products had what is known academically as the ‘halo effect,'” he said.

“These foods are considered to be okay to eat, the opposite of sinful, and because of that, people may overeat.”

Instead of eating one or two cookies, Dr. Jou said, people would eat the entire package and still be hungry.

“Such foods would be high glycemic index (GI) foods, where people’s blood sugar would rise and then they would be hungry soon after.”

Calories don’t add up

It’s not just our diet that has contributed to rising obesity rates.

People these days do less physical work because our jobs are becoming more sedentary and our homes are full of labor-saving devices.

“It’s a mix between the environment, the food environment, and really our lifestyle,” Dr. Yeo said.

Diet still plays a role, but Dr. Yeo said the problem with focusing on calories is that not all calories are created equal.

While our bodies have to work to get calories from unprocessed foods, he said, fast foods and convenience foods are “much more calorically available.”

“Even if we ate the exact same 400 calories, we would absorb a lot more calories than if we … ate steak or ate sweet corn,” he said.

This is one reason, he said, why you can’t decide which food is healthier simply by comparing its calorie count.

“Now we’re equating calories with health when that’s not what the calorie was designed for,” he said.

Another reason, he said, is that Atwater’s system often produces incorrect calorie counts.

The system only gives the caloric content of protein, carbohydrates and fat, he said.

“But we don’t eat proteins, carbohydrates and fats individually, do we? We eat food.”

He said the system is also unreliable, since the calorie count for meals is off by about 10 percent, on average.

“The problem is that 10 percent adds up pretty quickly. Ten percent is 200 calories of a 2,000-calorie meal, 10 percent of 20,000 calories is 2,000 calories.”

While Atwater’s system is attractive in its simplicity, Yeo said, that doesn’t change the fact that it’s inaccurate.

“It can be difficult, but I think we should be able to do better because this is wrong,” he said.

“I hate things that are wrong. We should try to fix it, because it’s wrong.”

– ABC Radio National Rear View