What’s the difference between Kcal and Calories?

once a week meal prep- thrivebeyondpills

Sharing is caring!

Imagine picking a pack of pasta while shopping for groceries at the mall and the nutritional information is in kcal, then you get to the dairy section and the nutritional information on the sugar-free yogurt is in calories. Huh! This begs the question – What’s the difference between kcal and calories.

When you see kcal and/or calories on food labels, do they mean anything to you? Or do you just regard them as technical food jargon?

This article explains what they are, their differences, and how you can use your newfound knowledge in your weight loss journey.

You’ve been told by myself and other experts in the fitness industry that you need to watch your caloric intake to lose weight and to do so, you need to befriend food labels and note the number of calories in almost everything you eat.

Counting calories is an important exercise if you want to lose weight or maintain a certain weight.

By counting the number of calories you take in daily, you can know exactly how much you are taking and from that, make changes to your diet, should it become necessary.

However, food labels can be a bit confusing if you are not familiar with the unit of measurement used. Please follow along as I explain the unit of measurement and show you how you can use the data to make healthier food choices.

What are calories? 

Simply put, calories are a measure of the energy found in foods and beverages or the energy you burn when you exercise.

This energy is important for everyday activities such as breathing, digesting your food intake, walking, etc and as established, you get them from foods and beverages. 

The unit with which calories are measured, however, varies depending on geographical location.

The unit used in China is different from that of Canada and from that of the United States of America.

So if you are eating something coming from these different regions, how do you from the available data, calculate how many calories you are consuming?

How are calories measured?

Calories can be measured in two ways: either as a large unit or a small unit. If the calorie is measured as a large unit, it is written with an uppercase c (C). If it is a small unit, it is written in lowercase (c). 

A large calorie unit is an estimate of the amount of energy needed to raise the temperature of one kilogram of water by one degree celsius i.e 1kg of water by 1oC. A small calorie unit, on the other hand, is an estimate of the amount of energy needed to raise the temperature of one gram of water by one degree celsius i.e 1g by 1oC. 

Thus, one large calorie equals 1,000 small calories i.e one kilocalorie (Kcal). Our focus, however, is on large calories as small calories do not matter when the conversation is nutrition. They still find use, though, in physics and chemistry research. 

While small calories do not hold much weight in nutrition, the term calories, whether uppercase or lowercase, is used to refer to the same amount of energy either got from food or burned during exercise.

Thus, in nutrition, one kilocalorie (1 kcal) is equal to one calorie (1 cal) – no conversion is needed.

Converting kilojoules(kJ) to kilocalories(kcal)

Where you need to convert is when the measure of energy in food is in kilojoules(kJ)

Sometimes, you come across food labels that express energy as kilojoules (kJ) and you get confused. Sometimes you go as far as dropping the food item like it’s hot because the number of calories is ridiculously higher than you expected.

There’s no need to panic or avoid your favorite food because the unit of calories is in kilojoules. It is still the same thing. You just have to convert it to kilocalories.

To convert from kilojoules to calories, divide the value of the kilojoule by four point two kilocalories.

It is actually 4.18 but for ease of calculation, you can approximate it to 4.2.

Let’s do simple mathematics.

1 kcal =  1kJ\4.18

Conversely, to convert from calories to kilojoules, multiply the value of the calories by 4.18

1kJ = 1kcal x 4.18

The unit in which calories are expressed depends on geographical location. It can either be expressed in kcal, kJ, or both. 

Energy is expressed in the following way in the following countries:

·         United States: Calories

·         Canada: Calories

·         European Union (EU): kJ and kcal

·         Australia and New Zealand: kJ or both kJ and kcal

·         China: kJ

Hence, the information on the label of your food item will likely be a reflection of where it was produced.

What is the basis on which calories are measured?

The number of calories a food or beverage contains is usually based on the amount of energy-supplying nutrients it contains. 

The three major energy-supplying nutrients (macronutrients) available are protein, carbohydrates, and fats. 

Fats provide nine calories per gram, which is 37.6 kJ while carbohydrates and proteins provide four calories each per gram (16.7kJ). Alcohol, while not a nutrient, also supplies a substantial amount of calories – seven per gram (29.3 kJ), to be exact.

When manufacturers determine the number of calories a food product contains, they usually estimate to the nearest one-gram increment.

Thus, if you were to quantify the number of calories from each macronutrient a food product has, your values might be a bit different from what is written on the food label. 

Another point worth mentioning is that if the food product contains fiber (typically classified as carbohydrate), it may contain fewer calories than what your calculations give you.

This is because fiber, depending on the type, is either non-digestible or improperly digested. Thus, it contributes no calories, or if it does, few.

How to calculate the number of calories you should eat in a day to lose weight

The number of calories you need depends on factors such as your gender, age, weight, and level of activity. A young man with a high level of activity will need more calories than an elderly woman with a low level of activity. 

Before you can start counting your daily caloric intake, you need to settle on the number of calories to aim at consuming per day. 

One assured way of calculating your caloric needs is the Mifflin-St Jeor equation. The equation factors in your age, weight, sex, and level of activity and it returns a figure for you to work with. You can use this calculator to estimate the number of calories you should be eating in a day to maintain your current weight.

To lose weight, however, you need to eat less than the number of calories you need to maintain your weight.

Let’s say you want to lose 20kg.

First of all, you need to know that losing 20kg sustainably via healthy eating will take some time. I usually encourage people to set the most realistic goal which is to aim to lose 0.5kg per week.

So if you want to lose 20kg, a very realistic plan to lose the weight sustainably is to plan to lose 0.5kg per week over the next 40 weeks.

Of course, a lot of people I work with achieve their goal way before this timeline but it is better than setting an unrealistic goal of losing 5kg per week only to get disappointed when you do not achieve your goal.

To lose 1 pound per week which is a little bit less than 0.5kg because 1kg is equivalent to 2.2pounds, you need to subtract 500 calories for the number of calories you calculated using the Mifflin-St Jeor equation.

The value you get is the number of calories you should eat in a day to lose weight.

How to count calories in meals

Having got the target number of calories, the next thing you need is to know which food combos offer you the best chance of meeting and not exceeding your caloric intake goals.

One sure way to do this is by preparing your meals at home.

Calorie counting makes it easier to lose weight and maintain your weight loss better.

Thanks to advancements in technology, it is easier to count calories today than it used to be. There are lots of apps and websites that help simplify the process. All you need to do is log in everything you eat, and they do the rest for you.

Below are some of the most popular free calorie-counting apps/websites: 

·         My Fitness Pal.

·         Lose It!

·         FatSecret.

·         Cron-o-meter.

·         SparkPeople.

Sometimes the information might not be as accurate as calculating the exact amount of calories in your food using the United States Department of Agriculture Database but you can definitely get a rough estimate to work with.

All you need to do to know if you’re on track is to check your weight at the same time weekly preferably using a digital scale.

If you’re not losing weight, then you’re probably underestimating the calories in your food or you’re overestimating the number of calories you burn from exercise.

Additionally, it might be that you need to incorporate other lifestyle changes such as ensuring adequate water intake or adequate sleep.

The benefit of counting calories and how to weigh and measure your portions

Studies have shown that people who track their food intake, even only irregularly, tend to lose more weight than those who do not. They are also able to maintain their weight loss better.

It also helps you combat overeating by giving you a better understanding of how much you are consuming per time. 

Effective calorie counting requires that you record your food portions correctly. To do this well, consider the following options:

Food scales

Weighing your food is the most accurate way of measuring how much food you are taking in. This can, however, be time-consuming and let’s face it, not totally practical. 

Measuring cups

This is a slightly quicker and easier method than using scales. It can, however, still be awkward and a little messy too. Imagine serving your jollof rice into a measuring cup first before transferring it to your plate.

You can however simply stick to eating 1 serving spoon of grains or carbs.


Comparing your meals to common items is quicker and easier and the chances of being made fun of are slimmer especially if you are away from home. The snag with this method is that it has a large margin for error. To shrink that margin, consider the following items you can compare your meals with when trying to manage your portion sizes:

·         1 serving of rice or pasta (1/2 a cup): a computer mouse or rounded handful.

·         1 serving of meat (3 oz): a deck of cards.

·         1 serving of fish (3 oz): a checkbook.

·         1 serving of fresh fruit (1/2 cup): a tennis ball.

·         1 serving of green leafy vegetables (1 cup): a baseball.

·         1 serving of vegetables (1/2 a cup): a computer mouse.

·         1 teaspoon of olive oil: 1 fingertip.

·         2 tablespoons of peanut butter: a ping pong ball.

 Whoops! You made it to the bottom line.

Bottom line

What’s the difference between Kcal and Calories?

In nutrition, one kilocalorie (1 kcal) is equal to one calorie (1 cal) – no conversion is needed. 

On the other hand, 1 kilocalorie(kcal) = 4.18 kilojoule(kJ). Therefore, to convert kilojoule to kilocalorie, divide the number of calories on the food label by 4.18 or 4.2.

Studies have shown that people who track their food intake, even only irregularly, tend to lose more weight than those who do not. They are also able to maintain their weight loss better.

The most practical method for counting calories has a large margin of error therefore, you should check your weight weekly or compare current pictures of yourself with old ones monthly to be sure you’re on track on your weight loss journey.

Please share the article with friends and don’t forget to follow me on FacebookAdebusola Adegbola Adefeso

2 thoughts on “What’s the difference between Kcal and Calories?”

  1. Setting realistic goals so that I won’t be disappointed. That’s the catch! Most of us who want to lose weight want to do so in as little time as possible.

    I certainly wish that I could! 😀

    Thank you so much Dr. Busola for this highly informative article.

Leave a Comment

Your email address will not be published.