Hello best health seekers!
Are you obsessed with calorie counts and trying to lose weight? Or maybe you count them in order to maintain a healthy diet. While calorie counts on food can be helpful, they are terribly misleading. If a calorie is just a calorie, 100 calories of soda, 100 calories of peanut butter and 100 calories of green beans will have the same effect on your weight but they won’t. Here’s why the calorie isn’t what you think it is, why understanding it will help free you from calorie counting, and what to avoid on a delicious and nutritious road to a healthier, thinner you.
What the Heck IS a Calorie?
A calorie is just a measure of energy and for some reason scientists pegged it to how much energy is needed to raise the temperature of 1 kilogram of water 1 degree Celsius.
Mmhm. Great. How the heck does that relate to food?
Every food has a calorie count. We take special notice of these because we’re told that in nutrition, calories refer to the energy people get from the food and drink they consume, and the energy they use in physical activity. Well, not exactly.
You see, food calories are based upon the energy released when it’s burned in a water experiment. Ever wonder how labelers know how many calories are in your box of macaroni and cheese? Originally, scientists placed food in a sealed container surrounded by water. The food was completely burned and the resulting rise in water temperature was measured. From that came the food’s calorie count, i.e. the energy used to raise the water’s temperature. This method is not frequently used today but a variant is.
Today’s scientists estimate calories. Food is no longer directly burned and measured. Instead, the system uses the average values of 4 cal/gram for protein, 4 cal/gram for carbohydrate, 9 cal/gram for fat and 7 cal/gram for alcohol. These macronutrient numbers were determined by burning and then averaging the values. Thus the label on an energy bar that contains 10 g of protein, 20 g of carbohydrate and 9 g of fat would read 201 calories.
But how do they know the food’s composition of protein, carbohydrates, fat and alcohol in the first place? Tables. Lots of tables. The FDA doesn’t state how a company should determine the nutrient content of their product for labeling purposes and does not prohibit the usage of “average” values from various databases so long as the company does so “in good faith.” Proximate values for most everything exist either with the USDA and industry organizations, broken down by macro- and micronutrient categories. In labeling, manufacturers can select information from these databases or through analyzing their own product samples. From these options comes your proximate calorie (and other nutrient) values. That label gets slapped on your food with very little fact-checking.
That’s why you’ll see the same calories (and other nutrient values) listed on your raw chicken or green beans regardless of the manufacturer, how it’s grown or actual composition. They’re all pretty much using the same tables and averages. The FDA doesn’t request samples and rarely investigates. Given the changes over the last few decades in how food is grown and its concurrent decline in nutritional value by 20% or more (see The Dorito Effect), depending on what and when information was last updated in the databases these numbers could be horribly misleading or just flat wrong.
Takeaway: The calorie count on your food label is an estimate, based on proximate values for macronutrients. It’s essentially the unit of energy released when food is burned and raises water temperature.
A Calorie Is Not A Calorie
A calorie is a unit of energy. This does not mean it is the energy you will get out of a food. Think about labeled calorie amounts as the potential energy stored in food, approximated during labeling, but that says nothing about how your body will store or use the food and its calories, let alone the impact of that food on your biochemical system, including weight or health.
The human body is a highly complex organism with elaborate processes that regulate our energy balance. If you’re just counting calories, you’re in for a world of disappointment on your weight loss or maintenance goals.
Here are 4 researched-based reasons why the same amount of calories for different foods (think 100 calories of soda vs broccoli) have different effects on your weight.
#1 – We Are Not One Size Fits All
When it comes to energy consumption, we all have different caloric needs. People have different metabolisms that burn energy at different rates. This means everyone requires different amounts of energy each day depending on overall general health, physical activity demands, sex, weight, height, and body shape. A baby or toddler versus a teenager or adult will have vastly different energy needs. So will a senior or pregnant woman. We are not one size fits all when it comes to calorie needs or how we will metabolize any incoming energy.
If you’re wondering about that 2,000 calories for women and 2,700 for men a day recommendation you’ve heard for decades or see on food labels, well, it doesn’t have any scientific basis. It was an average of self-reported surveys of calorie intake in the general population done back around 1990. Survey results found that males self-reported daily calorie intakes in the 2,000 to 3,000 range, and females reported intakes in the 1,600 to 2,200 range. From that some rounding was done to 2,000 for women and 2,700 for men and settled on for a standard. In other words, not only was the calorie standard not derived from scientific research that estimated energy needs based on age, height, weight and physical activity levels, but the levels were not even validated to ensure that the self-reported ranges were accurate.
So given this, why are we even using the 2,000 and 2,700 calorie standard today on labeling and in dietary recommendations, along with their equivalent fat, carbohydrate, and protein recommendations?
Good question. Actually, we shouldn’t be using them at all. In fact, a vast majority (68.6%) of the American population is overweight or obese and both men and women require nowhere near 2,000 calories a day to promote an ideal body weight.
Consider the following U.S. News examples of the estimated calorie needs from of a variety of people to illustrate this point:
- A normal weight 26-year-old woman who has a sedentary desk job but hits the gym three times a week for cardio or some yoga and is 5 feet 5 inches tall and 135 pounds probably maintains her healthy weight at about 1,800 calories per day.
- An overweight 35-year-old working mom with young kids at home and no time to exercise and is 5 foot 2 inches tall and 150 pounds is looking at just 1,200 calories per day to help shed some weight.
- A slightly overweight 55-year-old man who is 5 foot 9 inches tall and weighs 175 pounds, works in an office and hits the stationary bike for 30 minutes of cardio twice a week requires about 1,700 calories to lose those few extra pounds and maintain a healthier body weight.
- An overweight 65-year-old woman, 5 foot 4 inches tall and 165 pounds requires 1,500 to 1,700 calories to maintain her weight if she is very lightly active. To lose weight? She would need to reduce her intake to about 1,200 to 1,300 calories per day.
- A 45-year-old guy who’s 6 foot 4 inches and 325 pounds would probably have to eat about 1,900 calories per day to promote a desired level of weight loss.
The only people who need to eat 2,000 calories or more a day are very active and very fit adults and teenagers. We’re talking gym bunnies, student or professional athletes and people in professions with a lot of physical activity. Considering that this is nowhere near the majority of average Americans, we could all probably rethink our energy needs.
Takeaway: Daily energy needs vary based on a number of factors. That’s just caloric needs and does not take into account how various foods will impact how your body uses or stores the energy you take in. Ignore that daily recommended value on labels and definitely cap yourself at the 2000 level whether you are male or female. Unless you’re Olympic swimmer Michael Phelps.
#2 – Your Body Does Not Use All Food Equally
Different foods go through different biochemical pathways, some of which are inefficient and cause energy (calories) to be lost as heat. What does that mean? It means your body metabolizes protein, fat and carbohydrate foods differently. 100 calories of protein, 100 calories of carbs, and 100 calorie of fat will not equal the same weight gain or loss.
For instance, protein is used less efficiently than carbohydrates and fats. Fats are the most efficiently used so that only 2-3% of their calories are lost as heat, compared with 25% of protein calories and 6-8% of carb calories. Think of this as actual calorie capture.
Let’s illustrate this using a theoretical 100 calories each of protein, carbs and fats. At the end of the day, this would mean that 100 calories of protein would end up only as 75 calories, while 100 calories of fat would end up as 98 calories your body uses or stores. Protein is the least fattening macronutrient since 25% gets lost to heat versus only 2% for fat. This is why you see so many high-protein diets. Proteins have a metabolic advantage over the others because it takes more energy to metabolize and leaves less for you to store as weight gain.
But it’s not just protein. Whole foods also require more energy to digest than processed foods. Whole foods include fruits, vegetables, legumes, pulses, seeds and nuts. Basically everything else on the shelves is processed. Unfortunately, processed foods make up 66% of the standard American diet.
#3 – Foods Activate Different Levers for Hunger and Eating Behavior
Different foods and macronutrients have a major effect on the hormones and brain centers that control hunger and eating behavior.
Sticking with our protein example, studies show that protein:
- Leads to significantly reduced appetite, making you eat fewer calories automatically,
- Is by far the most filling macronutrient,
- If its intake is increased, will make you start losing weight without counting calories or controlling portions.
In one study, people who increased their protein intake to 30% of calories, automatically started eating 441 fewer calories per day and lost 11 pounds in 12 weeks. If you don’t want to go on a diet but simply tip the metabolic scales in your favor, adding more protein to your diet may be the simplest and most delicious way to cause automatic weight loss.
On the opposite end of the spectrum is sugar, a carbohydrate. For instance, even though fructose and glucose provide the same number of calories, fructose has far more negative effects on hormones, appetite and metabolic health. How?
- Ghrellin is a hunger hormone that goes up when hungry and down after you’ve eaten. Studies show fructose leads to higher ghrellin levels, and thereby hunger, than glucose.
- Fructose does not stimulate the satiety centers in your brain in the same way as glucose, leading to a reduced feeling of fullness.
- Consuming a lot of fructose can cause insulin resistance, abdominal fat gain, increased triglycerides, blood sugar and small, dense LDL compared to the exact same number of calories from glucose.
So basically sugar makes us hungrier and short-circuits our satiety centers and causes really bad problems for our insulin, weight, and cholesterol, among other negative health effects.
Keep in mind that fructose only has negative effects when eaten in excessive amounts and that added sugar and candy are its largest dietary sources. While fruits contain fructose, they’re also rich in fiber, water and provide significant chewing resistance, which mitigates the negative effects of the fructose. So avoid the candy and sugar and eat the fruit which also contains essential daily vitamins, minerals, water and dietary fiber.
#4 – When, Where and How Much Triggers
The foods you eat can have a huge impact on the biological processes that control when, what and how much you eat. Two key influences on this are satiety and blood sugar levels.
Ever notice that it’s easy to eat 500 calories of ice cream but you’d have to force yourself to eat 500 calories of eggs or broccoli? That’s because different foods have different satiety effects or greater or lesser feelings of fullness. We saw this with fructose found in candy and added sugars.
If you eat foods that are low on the satiety index, then you will be hungrier and end up eating more. If you choose foods that are high on the satiety index, you will end up eating less and losing weight. Examples of foods that are high on the satiety index are boiled potatoes, beef, eggs, beans and fruits (whole foods). Foods that are low on the index include donuts and cakes (processed foods). Whether or not you choose foods that are filling will have a major impact on your energy balance in the long-term.
Studies consistently show that low-carb diets lead to more weight loss than low-fat diets, often 2–3 times as much. One of the main reasons for this is that low-carb diets lead to drastically reduced appetite, so people start eating fewer calories without trying. Moreover, low-carb diets tend to include more protein than low-fat diets. Protein takes energy to metabolize and the body expends energy turning protein into glucose, plus protein is the most filling of the macronutrients.
Blood Sugar Levels
If you’ve gotten a headache from all the conflicting diet advice over the years, you’re not alone. However, one of the few things that almost everyone agrees on is that refined carbs are bad. These refined carbs include added sugars like sucrose and high-fructose corn syrup, as well as refined grain products like bread and pasta. Refined carbohydrates tend to be low in fiber and are digested and absorbed quickly, leading to rapid spikes in blood sugar. When you eat food that spikes blood sugar fast, it tends to lead to a crash in blood sugar a few hours later. When that happens, you get cravings for another high-carb snack which basically sends you on a never-ending roller-coaster of cravings and crashes.
Whether foods fall on the high or low-end of the glycemic index (GI) will greatly impact blood sugar levels. In one study, people served milkshakes identical in every respect except that one had high-GI and the other low-GI carbs, the high-GI milkshake caused increased hunger and cravings compared to the low-GI shake. Another study found that teenage boys ate 81% more calories during a high-GI meal compared to a low-GI meal.
The speed at which carb calories hit the system can have a dramatic effect on their potential to cause overeating and weight gain. Studies consistently show that people who eat the most high-GI foods are at the greatest risk of becoming obese and diabetic. That’s because not all carb calories are created equal. If you’re on a high-carb diet, it’s crucial to choose whole, unprocessed carb sources that contain fiber (whole foods). The fiber can reduce the rate at which the glucose enters your system.
Takeaway: Studies show that refined carbohydrates lead to faster and bigger spikes in blood sugar, which leads to cravings and increased food intake, among other negative metabolic effects. The remedy? Eating a diet of whole foods rather than processed ones.
Your Bottom Line
A calorie is not just a calorie. We all need calories but those requirements will vary based on a host of factors. When we take in calories, their composition will interact with how we regulate our metabolism, weight, appetite, immune system, insulin, digestive system, along with everything else. Some calories are “denser”, think fat over protein, while other calories like sugar and refined carbs will trick our hunger receptors and levels of fullness. The quality, not just quantity, of food and their nutrients guide our overall health and weight in a complex symbiosis with our biological processes.
This article focuses mainly on calories at the macronutrient levels (fat, protein, and carbs) but nutrients like vitamins and minerals will also greatly influence our health and waistlines. That says nothing about impacts from chemical additives, preservatives, emulsifiers, etc. that go into modern food or environmental influences like pesticides, water contamination, BPAs, and a host of others that seem to come out daily on the news.
What does seem abundantly clear from the research is that processed food is bad for us and that a whole foods diet is our first line of defense against many modern health problems. A whole foods diet keeps at bay the worst offenders when it comes to weight gain too. Start there, with the quality of your food. Ditch the fast food, heat and serve, ready to eat meals, bagged and boxed kits, and limit the refined grains that make up breads and pasta. Do this and you won’t have to count calories.
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“How many calories do you need?”, https://www.medicalnewstoday.com/articles/263028.php
“How Do Food Manufacturers Calculate the Calorie Count of Packaged Foods?”, Jim Painter, ScientificAmerican.com, May 19, 2003, https://www.scientificamerican.com/article/how-do-food-manufacturers/
USDA Food Composition Databases, https://ndb.nal.usda.gov/ndb/
Guidance for Industry: Food Labeling Guide, FDA, January 2013, downloadable at https://www.fda.gov/Food/GuidanceRegulation/GuidanceDocumentsRegulatoryInformation/LabelingNutrition/ucm2006828.htm
Who Actually Needs a 2,000-Calorie Diet?, Tamara Duker Freuman, U.S. News & World Report, June 14, 2016, https://health.usnews.com/health-news/blogs/eat-run/articles/2016-06-14/who-actually-needs-a-2-000-calorie-diet
“6 Reasons Why a Calorie Is Not a Calorie”, Kris Gunnars, Healthline.com, May 8, 2018, https://www.healthline.com/nutrition/6-reasons-why-a-calorie-is-not-a-calorie