UNDERSTANDING CALORIES

THE ‘CALORIE’ ORIGIN:

A calorie is a unit of energy. In nutrition, ‘calories’ refers to the energy we get from the food we eat that fuels us to be able to carry out daily physical activity, exercise and every day movements and body functions. The foods we buy from the supermarket reference the calories contained within each food on the packet. We can also learn about the caloric content of individual food ingredients using food tracking apps such as chronometer. 

‘One calorie’ of energy is measured by the ability to change the temperature of 1 gram of water by 1 degree centigrade. 

The calories (kcal) is the original unit of measurement and is an international unit of measurement used in technical and scientific research. The kilojoule was later created. It is also a measure of energy or work. One joule is the amount of work/energy it takes for a force of one newton to be exerted over a distance of one meter. The unit of energy 'the Joule’ was named after English Physicist James Prescott Joule who studied the relationship between heat and mechanical work. 

Both the calories and the kilojoule are used interchangeably in relation to the energy in each food. Different countries use different measurements. The calorie is considered the imperial system whereas kilojoules are used in the metric system.

FOOD ENERGY:

We need the energy and nutrients from the food we eat for our body to carry out each systems functions and to have the energy we need to move, carry out or daily functions, exercise, perform and simply stay alive.

Each of the three macro nutrients contain a different number of calories per gram of food. Carbohydrates provide four calories of energy per gram, protein also four calories per gram and fat provides nine calories per gram. 

However the relationship between calories and reaching our optimal health, wellness, fitness, performance and a lean physique, is not as simple as a mathematical calculation and not all calories are considered equal. We have become accustomed to counting the number we consume per day, staying within a set range that we believe is right for us to; maintain weight, gain weight or lose weight, and it has become the norm to believe that manipulating that number up or down will determine our subsequent weight loss/fat loss. This is not so.

WEIGHT LOSS:

Weight loss, which should be classified more accurately as fat loss, as it is the amount of body fat we are holding that we want to reduce not the physical weight of our body, as that doesn’t directly affect us day to day. It has, however become a tool we use to measure our success in fat loss, although that in itself is also not completely black and white. There are many other variables that affect weight including muscle, fluid, sleep quality, stress and cortisol levels, hormonal influences, time of day, what we’re wearing, if we have been to the toilet and what we have eaten and what fluids we have consumed.

So what’s the truth, what’s important and how do we navigate this? 

There is definitely some merit in understanding calories and being somewhat aware of what we’re consuming. If we consume 6,000 kcals a day, and we’re not an Olympic swimmer, then logically we can assume we’re quite likely to increase our body fat amount. If we consume a 500 kcal per day diet, we can assume we are quite likely to quickly become malnourished and likely cause some longer term hormonal and metabolic disturbances.

We hear the common representation that a man should consume approx 3,000 kcal per day and a woman approx 2,000 kcal per day, however little education and explanation is given beyond this. In my opinion the main reason for this is that the educators haven’t done the research and experiments themselves to discover the relationship between the many variables. Including, the quantities we consume,  the percentage of each macro nutrient, the health of the individual, the activity levels of the individual, stress levels of the individual, eating habits, fluctuation between eating patterns, how one trains in relation to the way they're eating, the energy system their body tends towards and more specifically where these calories are actually coming from and if even that alone makes a difference. 

At a more advanced level, especially amongst athletes, there is much research and experimentation done around the effect that calories from each different macronutrient has on the body.

If done properly, and by that I mean, if understood correctly, then a diet of predominantly fat calories, can be consumed at a highly quantity than a diet of carbohydrates for energy, and as a result, a reduction in body fat occurs. In contrast, if we  consume an equal caloric intake of predominantly carbohydrates, the body is likely to increase in weight or body fat. This is due to the body’s need for different forms of fuel at different times and also dependant on which energy source the individual has trained/conditioned their body to adapt to.

Like fuel for a car, we can fuel our body’s with a different energy source and we will function a different way depending on the engine we have and whether we keep feeding the best fuel for that system or if we chop and changed between fuels without structure or purpose.

This shows us that there are more factors influencing weight/fat gain than just calories alone. Factors such as hormone levels, blood glucose levels, cortisol levels, ketone levels, the effects of each food nutrient on the systems of the body, the amount of water each food type retains within the body and the effect of different macro nutrients on the functioning and efficiency of the metabolism.

So have we completely misjudged the way the body handles food and weight loss? Not enough testing or research has been done to confirm this but I am certainly sure we have. I have done an amount of research myself and have more to do. It is an exciting space with much more to discover and benefit from.

Irrespective of which calories come from which foods and how they effect us differently, what is also important is what we do with these calories, our daily activities, exercise, training and our personal lifestyle. 

There are a number of calculations and formulas that we look at when planning and understanding what will work for us as a starting point. From here we can experiment with our own body, and this will be individual to you and different to the next person. So we must take a starting caloric number and then test to see if that is in fact accurate for us or if we need to change it to suit us.

FORMULAS:

The different formulas we look at when considering our total daily energy expenditure (TDEE) and the approximate number of daily calories we need are; resting metabolic rate (RMR), non-exercise activity thermogenesis (NEAT), thermic effect of food (TEF), exercise energy expenditure (EEE) and others to consider are; low energy availability (LEA) and relative energy deficiency (RED).

There are a number of different methods of calculating the different formulas. Below I explain what each formula means, how to do the calculations and what we can use them for.

CALCULATING RMR:

RMR can be calculated in the following ways:

OPTION 1 - Basic formula

24 - 26 kcal per Kilo of Body Weight

OPTION 2 - The Cunningham Method

370 + (21.6 x FAT FREE LEAN MASS kg)

** KG x 0.17 (%) = FAT FREE MASS

OPTION 3 - The Mifflin St Jeor method for women

(9.99 x KG) + (6.25 x CM) - (4.92 x AGE) - 161

699.3 + 1093.75 - 226.32 - 161 = 1,385KCAL

OPTION 4 - The Harris Benedict method for women:

655.1 + (9.563 x KG) + (1.850 x CM) - (4.676 x AGE)

655.1 + 650 + 323 - 215 = 1,413

NON-EXERCISE ACTIVITY THERMOGENESIS - NEAT:

NEAT is the amount of energy the body requires to carry out regular daily activities. NEAT accounts for 10-15% of TDEE

To calculate NEAT multiple RMR by;

Sedentary Lifestyle (1.25)

Mostly Sedentary Lifestyle (1.5)

Athlete doing 1 hour Training per day (1.75)

Active Job equivalent to walking 6 miles per day (1.75)

THERMIC EFFECT OF FOOD - TEF:

The thermic effect of food is the amount of energy the body uses to assimilate, process and digest the foods we eat. TEF accounts for 10% of TDEE. Macro Nutrients have different TEF %’s:

(Fats 3% of cals consumed) 

(Carbs 5-10% of cals consumed) 

(Protein 20-30% of cals consumed) 

A simple calculation often used is RMR x 0.1

EXERCISE ENERGY EXPENDITURE:

Exercise energy expenditure is the amount of calories we burn during training and exercise. The amount we burn depends on the type of training we’re doing, the duration and the intensity.

TRAINING SESSION INTENSITY:

The calories we burn during exercise depends on the activity, the duration and the intensity as well as your gender, age, weight, fitness and health.

It can range from 100 kcal to a few thousand calories when doing a long distance, high intensity marathon.

EXAMPLE TOTAL DAILY ENERGY EXPENDITURE CALCULATION:

A lady weighing 65 kilos with a sedentary lifestyle, who walks for 30min per day.

RMR: 25 x 65 kilos = 1,625 kcal

NEAT: 1,625 kcal x 1.25 = 2,031 kcal

TEF: 162 kcal

EEE/TRAINING SESSION INTENSITY: 170 kcal

TDEE: 3,818kcal

LOW ENERGY AVAILABILITY - LEA:

Low energy availability is when the energy required for exercise, in the form of calories is too low to safely exercise. In other words, we’re not fuelling ourselves adequately with our nutrition. This becomes a problem if it is left and we do not address it. Training capacity is reduced, fatigue occurs, injury and over training become a risk. The metabolism is hindered and our ability to lose weight is challenged and a number of other health risks can occur.

RELATIVE ENERGY DEFICIENCY - RED:

Relative energy deficient in sport represents a decline in an athletes performance and occurs when the athlete does not consume adequate nutrition to support their training demands.

During activity, the body burns calories from all 3 macros, carbs, fats and proteins. If we have a reading on our smart watch of burning 700 kcals during a workout, this doesn’t determine which macro nutrients were burnt. 

Carbs need to be replaced (if we are on an eating plan fuelled by carbohydrates). Fats don’t need to be replace if you are want to lose fat unless you are following a ketosis eating plan.

FINAL THOUGHT:

How we fuel our body is much more than just calories in Vs calories out in order to lose weight.

The health of our body, it’s ability to function at a high level, our energy, hormonal balance, our moods, our ability to get lean, stay lean and have energy to exercise or perform if we’re an athlete needs to be considered also and is all affected by how we eat.

How we fuel our body determines which energy system our body uses to function and subsequently will determine our health, our body composition, our digestion, how we train and the energy we have available.

If you want to change your body composition or change your state of health, energy or performance, be sure to do the research or request the help of a professional.

BE WELL, TRAIN HARD AND HAVE FUN!!