Working out is only part of the fitness solution. In fact, it's arguably not even the most important part of it.
So what's the most important part? Answer: your diet.
As I explain in my 6 mantras to keep in mind when working out, 'getting fit' is like fine-tuning a car. For some, the most important part of the process is improving the car's speed, for some it's making upgrades to the body work. In both cases, neither of these goals can be achieved without the right tools.
The tools are your diet. Without the right amount of calories, protein, carbohydrates, fats, vitamins, minerals, and water, working out is only going to get you so far.
In this first part of the 'Build Your Ideal Diet' series, I will show you how to estimate your daily energy needs.
Calories and weight
Before we get started, we first need to look at the unit we're going to refer to throughout this article: the calorie.
A calorie is a unit of energy. One small calorie (cal) is the amount of heat energy needed to raise the temperature of 1 gram of water by 1 degree Celsius. One large calorie (kcal) is the amount of heat energy needed to cause the same change in 1 kilogram of water.
Food is made up of energy and calories (in most instances kcals) are the chosen unit for measuring the amount of energy it contains.
We need the energy provided in food to perform everything we do, from exercising to sleeping. For the average man, the NHS currently recommends between 2,500 calories per day. For the average women, 2,000 calories per day is recommended.
These numbers are for the average person to maintain their weight, i.e. neither gain nor lose weight. As an equation, this is expressed as:
Energy intake = energy output
Of course, as these are estimates based on the 'average' man and woman, many factors can change the suitability of these numbers for each individual, including:
Age
Height
Weight
Lifestyle factors
Biological factors
Medications
Thankfully, there are ways we can tailor these numbers to each person.
Estimating your daily caloric needs
There are many equations you can use to estimate the right calories for you and your goals. For the sake of simplicity though, we will be using the following equation:
Basal metabolic rate x physical activity level*
*It should be noted that a third element is usually included in this equation: thermogenesis. This refers to the amount of heat produced through physiological processes. However, this is difficult to measure outside of a laboratory setting and has therefore been excluded.
Calculating basal metabolic rate
First to be calculated is our basal metabolic rate, or BMR. This is a measure of the amount of energy we use at rest. In order to calculate BMR, we will use the Schofield equation.
The Schofield equation is a very simple equation for estimating BMR that is based on both gender and age. To calculate your BMR, choose your age group and your gender from the list below.
Age: 10–17
Male: 17.7 x weight (kg) + 657
Female: 13.4 x weight (kg) + 692
Age: 18–29
Male: (15.1 x weight [kg]) + 692
Female: (14.8 x weight [kg]) + 487
Age: 30–59
Male: (11.5 x weight [kg]) + 873
Female: (8.3 x weight [kg]) + 846
Age: 60–74
Male: (11.9 x weight [kg]) + 700
Female: (9.2 x weight [kg]) + 687
As an example, Anna is a 24-year-old female who weighs 64 kg. Her BMR would be:
(14.8 x 64) +487 = 1434 kcal
Estimating physical activity level
Considering BMR shows how many calories are needed to maintain normal bodily function at rest, we now need to factor in your Physical Activity Level (PAL).
To estimate your activity level, choose your work activity level, your leisure (social and exercising levels) activity level, and your gender from below.
Work activity level: light
(e.g. office workers, housewives, unemployed)
Leisure activity level: non-active
Male: 1.4 / Female: 1.4
Leisure activity level: moderately active
Male: 1.5 / Female: 1.5
Leisure activity level: very active
Male: 1.6 / Female: 1.6
Work activity level: moderate
(e.g. retail workers, transport workers, students)
Leisure activity level: non-active
Male: 1.6 / Female: 1.5
Leisure activity level: moderately active
Male: 1.7 / Female: 1.6
Leisure activity level: very active
Male: 1.8 / Female: 1.7
Work activity level: heavy
(e.g. equipment operators, labourers, construction workers)
Leisure activity level: non-active
Male: 1.7 / Female: 1.5
Leisure activity level: moderately active
Male: 1.8 / Female: 1.6
Leisure activity level: very active
Male: 1.9 / Female: 1.7
Using our example of Anna, she is a retail worker (moderate work activity level) who visits the gym every day (very active leisure activity level). Her PAL would be 1.7.
Putting the pieces together
With both your BMR and your PAL calculated, all you need to do now is plug them into the equation above, and hey presto! You now have an estimate for the amount of calories you need to consume to maintain your weight.
For Anna, the number of calories she should consume per day to maintain her weight is:
1434.2 x 1.7 = 2438 kcal
Weight gain or weight loss?
If you wish to maintain your weight, the number you have calculated so far is sufficient. You can now move onto part 2 of this series where I show you how to calculate the right balance of macronutrients for you.
For those of you who would like to either lose or gain weight though, there is one final step.
Earlier, I showed you the equation for maintaining weight as energy intake = energy output. To change your weight, there are two more versions of this equation:
To gain weight: Energy intake > energy output
To lose weight: Energy intake < energy output
Gaining weight
Although we associate gaining weight with something bad, for many of us, gaining weight is actually our goal. Specifically, if we're trying to build muscle.
Now, technically speaking, muscle can be built using your estimated caloric needs to maintain your weight. This is because, by correcting your intake of macronutrients (proteins, carbohydrates and fats) and altering your training methods, you should be able to lose fat whilst building muscle. This is commonly referred to as 'body recomposition'.
This is however a disputed area. Many people believe that the most effective way to gain muscle is to 'bulk' and 'cut'. Bulking involves eating more calories than your estimated daily caloric needs which, when combined with a sufficient exercise programme, aims to gain as much muscle as possible. Cutting then involves eating fewer than your estimated daily caloric needs, with the aim to lose as much fat as possible. The result should then be a leaner, more muscly body.
In order to gain weight, a caloric surplus – i.e. the extra amount of calories to be consumed on top of your daily caloric needs to maintain your weight – of 500 calories should lead to roughly 1 lb of weight gain per week. Beware though, although the intention is to gain as much muscle as possible (which depends on a lot of factors, in particular your exercise programme), being in a caloric surplus for long enough will likely also lead to fat gain.
Losing weight
In order to lose weight, a caloric deficit of 500 calories should lead to a weight loss of roughly 1 lb a week. Similar to being in a caloric surplus though, there is a catch. Being in a caloric deficit for long enough can lead to losses in lean muscle as well as fat, particularly if your exercise programme is insufficient. This is less likely than the opposing scenario (as the body favours burning extra energy stores in the form of fat over muscle) but is still a possibility. Losses in strength can also result from this approach.
Now that you've calculated your estimated energy needs, move onto the second part of this series: Calculating Your Macronutrients.
Disclaimer: I am not a doctor or medical professional. The information I provide on this website is based on my personal experience and my experience as a Personal Trainer. Use of this information is strictly at your own risk. In addition, the information provided on this website is not intended to be a substitute for professional medical advice, diagnosis or treatment. Never disregard professional medical advice, or delay in seeking it, because of something you have read on this website. Never rely on information on this website in place of seeking professional medical advice.
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