Most people who count calories for weight loss or weight management assume it’s an exact science. It’s not. Here we outline 5 reasons calorie counting (i.e. logging your food to calculate intake) is fundamentally flawed.
Make no mistake, the principles of energy balance work:
Take in more calories/energy than you expend, you gain weight.
Take in fewer calories/energy than you expend, you lose weight.
However, counting calories as a way to try to know, and control, your energy intake is fundamentally — sometimes hopelessly — flawed.
For starters, you can’t really trust that the calorie (and macronutrient) numbers you see on food packages are accurate. You see, the way they’re calculated — if they’re calculated at all — is surprisingly imprecise.
Plus, even if food package numbers were precise, once the food is cooked, or chopped, or blended, the amount of energy available for digestion and absorption changes.
Then there’s what happens once that food enters your body…
In the end, even something that seems as simple as knowing how many calories you’re taking in (and absorbing) can be influenced by dozens of unexpected factors.
That’s why, today, we share the 5 biggest (and surprising) problems with calorie counting as it relates to the “calories in” side of the energy balance equation.
Want to download the infographic and have it on hand to show friends (or clients)? Click here for printer- and tablet-friendly versions.
Okay, we know all of this is going to blow some minds. Especially with the current fascination around calorie tracker websites and apps.
But once you’ve had some time to let it sink in, please download the infographic and spread the word.
And if you want to learn about the other side of the calorie counting equation, check out Part 2: ‘Calories Out’.
Some important notes
For the scientists among our readership: Throughout the introduction and infographic, ‘calories’ — lowercase ‘c’, refers to kilocalories — or ‘Calories’. Over time, popular language has lost the big C/little c distinction.
Section 1: “Calorie counts are imprecise.”
In 1896, Wilbur O. Atwater, the father of food calories, sampled hundreds specimens of food products collected at the World’s Fair. Atwater calculated the caloric value of each food using bomb calorimetry, a very accurate and precise method for measuring total energy in any object.
Interestingly, a wide range of total caloric values was found, even for single food types (i.e. apples) bred, picked, and stored identically. As a result, the Food and Agriculture Organization of the United Nations said in a statement:
“Foods, being biological materials, exhibit variations in composition; therefore a database cannot accurately predict the composition of any given single sample of food.”
Even more interesting: Atwater’s total caloric ranges were used to produce the kcal averages still in use on labels and in databases today. (They’re over 100 years old!) For a given food these values could be up to 50% off, as outlined in the infographic.
Bottom line: The trust many of us feel that calorie labels and nutrient databases are exact (or even accurate and reliable) may be misguided.
Section 2: “Calorie counts that reflect only what we’ll absorb.”
The averages of 4 kcals per gram of protein, 9 kcals per gram of fat, and 4 kcals per gram of carbohydrates — meant to reflect how much energy we actually absorb from food since these values are lower than the energy measured in the food — are Atwater general correction factors developed in 1897 and still in use today.
Subsequently it’s been discovered that carbohydrates high in fiber have different correction factors, depending on the type of fiber (and even your gut bacteria / microbiota).
It’s also been discovered that energy absorption from protein varies. Typical absorption from animal protein is higher than the general Atwater factor — for example, 4.36 kcals per gram of protein in eggs — and lower from most vegetables — generally 2.44 kcals per gram of protein. The revised absorption averages are called Atwater specific correction factors.
Calories on food labels usually use the general factors while the USDA database uses the specific factors.
Further complicating the question of absorption, a new correction factor was developed to take into account the energy burned through digestion of various macronutrients.
Livesey’s Net Metabolizable Energy values are:
- protein, 3.2 kcals per gram;
- fat, 8.9 kcals per gram;
- available carbohydrates, 3.8 kcals per gram; and
- fermentable carbohydrates, 1.9 kcals per gram.
Bottom line: The idea that a gram of any protein yields 4 kcal, a gram of any fat yields 9 kcal, and a gram of any carbohydrate yields 4 kcal is a gross oversimplification that could have significant implications when trying to control and balance calorie intake.
Section 5: “People aren’t great at eyeballing portion sizes.”
Research shows the people are generally terrible at estimating caloric intake. Even trained nutritionists underestimate calories in meals by an average of 30 percent.
We often get the portion sizes wrong too. When trying to serve ourselves 1 tablespoon of, say, peanut butter, we often end up getting much more than an actual tablespoon. And it doesn’t just happen once in a while… it happens most of the time.
Passionate about nutrition and health?
If so, and you’d like to learn more about it, consider the Precision Nutrition Level 1 Certification. Our next group kicks off shortly.
What’s it all about?
The Precision Nutrition Level 1 Certification is the world’s most respected nutrition education program. It gives you the knowledge, systems, and tools to really understand how food influences a person’s health and fitness. Plus the ability to turn that knowledge into a thriving coaching practice.
Developed over 15 years, and proven with over 100,000 clients, the Level 1 curriculum stands alone as the authority on the science of nutrition and the art of coaching.
Whether you’re already mid-career, or just starting out, the Level 1 Certification is your springboard to a deeper understanding of nutrition, the authority to coach it, and the ability to turn what you know into results.
[Of course, if you’re already a student or graduate of the Level 1 Certification, check out our Level 2 Certification Master Class. It’s an exclusive, year-long mentorship designed for elite professionals looking to master the art of coaching and be part of the top 1% of health and fitness coaches in the world.]
Interested? Add your name to the presale list. You’ll save up to 44% and secure your spot 24 hours before everyone else.
We’ll be opening up spots in our next Precision Nutrition Level 1 Certification on Wednesday, October 2nd, 2019.
If you want to find out more, we’ve set up the following presale list, which gives you two advantages.
- Pay less than everyone else. We like to reward people who are eager to boost their credentials and are ready to commit to getting the education they need. So we’re offering a discount of up to 44% off the general price when you sign up for the presale list.
- Sign up 24 hours before the general public and increase your chances of getting a spot. We only open the certification program twice per year. Due to high demand, spots in the program are limited and have historically sold out in a matter of hours. But when you sign up for the presale list, we’ll give you the opportunity to register a full 24 hours before anyone else.
If you’re ready for a deeper understanding of nutrition, the authority to coach it, and the ability to turn what you know into results… this is your chance to see what the world’s top professional nutrition coaching system can do for you.