What are Calories?

Contrary to the quotes you see on social media, calories are not little monsters that live in your wardrobe and sew your clothes a little tighter every night. In fact, there’s nothing scary about them at all! In this article, Barney St Anton discusses the subject of calories and your goal as well as;

• The concept of energy balance.
• How to accurately estimate and adjust caloric intake for your goals.
• Plus, valuable tools that may help you along the way.

You have likely encountered calories when looking at food packaging, on a restaurant menu, or even on the screens of the treadmill at your gym. However, you most likely do not know what a calorie actually is.

The scientific definition of a calorie is “the energy needed to raise the temperature of 1 gram of water by 1 °C”.

To put it simply, a calorie is a unit of energy. Calories are the energy currency your clients require for growth, metabolism and other bodily functions. This occurs via complex metabolic processes involving various enzymes and hormones. Foods that contain calories are required in large amounts and are called ‘macronutrients’ (carbohydrates, fat, protein and alcohol), which we’ll learn more about in future articles.

Why are calories necessary for your goal?

Nutrition can, at times, be a confusing topic, with various sources touting contradictory claims. For every ‘expert’ who preaches the benefits of a low-carbohydrate ketogenic diet, there is another who supports an opposing approach.

The ketogenic diet is a high-fat, adequate-protein, low-carbohydrate diet that in medicine is used mainly to treat hard-to-control epilepsy in children. The diet forces the body to burn fats rather than carbohydrates.

For many, it can be difficult to select a dietary approach, often falling victim to the misinformed endorsements of celebrities or influencers. There is, however, one key concept that most people can understand and believe. To lose weight, you need to eat less and move more, and the reverse will likely result in weight gain. The key factor that governs the success of every nutrition plan or diet is the relationship between calories in and calories out, which provides an ‘energy balance’.

Energy Balance

Energy balance occurs when your energy intake, eg food and alcohol intake, perfectly match your energy expenditure. This means your physical activity and basal metabolism in particular. This means that you aren’t over or under-eating but consuming just the right amount of energy for your current expenditure. If it were possible to maintain energy balance, a near impossibility, you would remain roughly the same weight year after year. Daily fluctuations would occur due to factors such as water intake, the amount of food in your gut and the menstrual cycle.

Energy balance is the foundation of nutrition for body composition and has the biggest influence on dietary success. To improve body composition by losing body fat and/or gaining lean muscle mass, the number one priority of their nutrition programme should aim for energy balance.

Energy Intake

Energy intake refers to anything we consume that contains energy in the form of calories. This is influenced on a daily basis by the intake of:

• Food: starches, vegetables, fruit, meat, dairy and yummy stuff too
• Beverages: fruit juices, milk, and alcohol, for example

Throughout the rest of this article, we will discuss how you can alter your energy intake to achieve your goals.

Energy Expenditure

Energy expenditure refers to anything we do that uses energy in the form of calories. It is affected by some factors that can be easily altered, such as physical activity, and some that cannot be easily altered, such as keeping warm, i.e., thermal regulation, and basal metabolism.

Weight Loss and Gain

Negative Energy Balance leading to weight loss

Negative energy balance occurs when energy intake is lower than energy expenditure. This may be a result from restricted intake through dieting. An increase in physical activity, or a combination of activity and diet appears most effective. The result is an energy deficit that the body must overcome in order to function. The body utilises stored energy in the form of glycogen within fat & muscle tissue to supply the required energy. The breakdown of bodily tissue in this manner results in weight loss as those energy stores are utilised.

A healthy individual’s negative energy balance results in weight loss

Positive Energy Balance leading to weight gain

Positive energy balance occurs when energy intake is higher than energy expenditure. This may result from increased intake or decreased physical activity. More often than not, it is a combination of both. Epidemiologists use the term “Obesogenic environment” to describe how the Western world is perfectly set up for a desk-bound and inactive lifestyle with a diet that is rich in calories but deficient in nutrients. This creates an energy surplus with the excess energy being stored as fat, muscle or glycogen. This increases body tissue mass and so results in weight gain. 

A healthy individual’s positive energy balance results in weight gain

Estimating Energy Balance

Consuming the correct energy requirements for you and your goals is an essential component of anybody composition-focused diet. Whilst it is very difficult to calculate your energy requirements, there are a number of tools available to make an accurate estimate. These include:

• The Mifflin-St Joer Equation
• InBody testing (available through the LED Seaton Fitness Centre)

 

METHOD ONE
The Mifflin-St Joer Equation

Sachiko T St. Jeor was a professor and the director of the nutrition education and research program at the University of Nevada School of Medicine. Working with Mark D. Mifflin and other colleagues, they derived a mathematical equation to predict energy requirements. The equation was named the Mifflin-St Jeor equation. Research has suggested this equation is more reliable than other equations tested, such as the Harris-Benedict equation. The equation is a relatively quick and simple method to estimate the energy intake required to achieve energy balance accounting for both basal metabolic rate and physical activity. There are calculators available online, and you can even create an Excel spreadsheet to calculate this for you (as I have done for my clients). However, for those interested, I have outlined the equation below.

Energy requirements = Basal Metabolic Rate x physical activity

BMR (Basal Metabolic Rate)

• Male BMR: (10 x weight (kg)) + (6.25 x height (cm)) – (5 x age (years)) + 5
• Female BMR: (10 x weight (kg)) + (6.25 x height (cm)) – (5 x age (years)) – 161

Physical activity

• Sedentary – BMR x 1.2
• Lightly active – light exercise or sports 1-3 days per week: BMR x 1.375
• Moderately active – moderate exercise or sports 3-5 days per week: BMR x 1.55
• Very active – hard exercise or sports 6-7 days per week: BMR x 1.725
• Extremely active – very hard exercise, sports or training twice a day: BMR x 1.9

Worked example: 

• Gender – male
• Weight – 89.4 kg
• Height – 181 cm
• Age – 25 years
• My BMR = ((10 x 89.4) + (6.25 x 181) – (5 x 25)) + 5
• = ((894) + (1,131) – (125)) + 5
• = (1,900) + 5
• = 1,905

According to the Mifflin-St Jeor equation, my BMR is approximately 1,905 calories. Currently, I train 3-4 days per week and have a relatively active job as a gym manager, so I would categorise myself as ‘moderately active’, assigning myself a physical activity score of 1.55.

Energy requirements = BMR x physical activity = 1,905 x 1.55 = 2,953

The Mifflin-St Jeor equation estimates that in order to achieve energy balance, the example above would require consuming 2,953 calories daily. That’s roughly the equivalent of 31 apples! In theory, if we were to consume this number of calories daily, we would not gain or lose weight but instead simply maintain our body weight. In practice, it’s very rare for anyone to want to maintain their current body weight whilst focusing on improving strength, cardiovascular performance or flexibility, for example. Many want to either lose body fat or increase muscle mass with the ultimate goal of enhancing body composition.

METHOD TWO
The InBody Test

If you don’t fancy getting a calculator out or would like to gain insight into important health measures such as hydration status, visceral fat levels and waist-to-hip ratio, fear not! InBody testing is another very, very simple means of estimating energy requirements. Members can book an InBody test at my centre. David took this test just after Lockdown ended so he could assess his own goals. You can read about his experience in Body Fat and Segmental Analysis

The InBody test follows similar principles to calculate your BMR. However, it can estimate body fat percentage and lean body mass in further detail via bio-electrical impedance analysis. Since we know lean muscle tissue requires more calories than body fat, we can be sure that estimates from an InBody test are more accurate in athletic populations such as gym users.

Adjusting Energy Balance for Your Goal

Setting realistic targets for weight loss is critical. You may have lofty goals to lose X amount of body fat weight in Y number of weeks. However, this is only achievable through unsustainable crash diet methods. As such, I strongly suggest starting with the aim of losing 1lb per week, treating any extra loss as a bonus. Whilst aiming to lose 1lb a week may not seem significant, such an approach ensures the majority of weight lost is fat and not lean mass compared with losing higher amounts in shorter time frames. Given that 1lb of human body fat is equal to approximately 3,500 calories of energy, a deficit of 3,500 calories is needed to achieve the above. As there are 7 days in a week, we need to create a deficit of 500 calories per day.

Worked example:
Intake for -1lb/week = energy balance – 500
= 2,953 – 500
= 2,453 calories

Furthermore, I strongly suggest a slightly more conservative approach when looking to increase body mass in order to minimise the accumulation of excess body fat. As a result, an energy surplus of just 1,750 calories per week, or 250 per day, is likely a reasonable starting point. Of course, this energy surplus could also be achieved by reducing physical activity, but this would be counter-productive for those aiming to improve muscle size.

Worked example: 
Intake for +0.5lb/week = energy balance + 250
= 2,953 + 250
= 3,203 calories

Tracking Calorie Intake

A simple and effective way to track calorie intake is through Apps such as MyFitnessPal. Using this App. You can record your dietary intake by scanning bar codes, uploading recipes or searching the database to find popular household items. This will not only allow you to track your caloric intake but will also provide insight into macro/micronutrient intake. Additionally, you will have the capacity to estimate physical activity expenditure as well. As you become more familiar with this process, look at food labels when you are shopping so you can make informed choices and find alternative sources of food energy.

 

*** Barney St Anton works for LED Fitness Centre and gained a Master’s in nutrition from Exeter University.

Thank you for reading “Calories You and Your Goal”, written and researched by Barney St Anton

Published by Busypencilcase Communications & Publications. Est. 2015

January 2021. Modified January 2025