# How much should you be eating per day?

Do you know how much you should eat and drink per day? If you have any kind of fitness goal be it weight-related or fitness related you really need to know. Government guidelines of Male 2500Kcal a day and Female 2000Kcal a day are often wrong for the majority of us.

Thankfully there is a way to work out your individual amounts.

We are all built differently and so it goes to stand that we will all have different nutritional demands. Hopefully we all know that it is food and drink that gives us energy and commonly we see this as calories, or kilocalories (kcal). We look at the kilocalorie amount when looking at the nutritional information of food. For example, if we look at the Nutritional information of a banana we find out the following:

Amount per 100g
Calories 89Kcal
Total Fat 0.3g
Total Carbohydrate 23g
Protein 1.1g
(There is normally far more information on the food label, but for this post, we shall use just the basic figures)

Therefore, if we eat 100g of banana, our bodies get 89Kcal worth of energy. The figures above for Fats, Carbohydrates and Protein are the amounts of each Macro-nutrient in the banana which combine to make up the calorie total.

How do we work out our individual amounts then per day? For this we need to look at your BMR (Basal-metabolic-rate). This is how many calories your body burns at rest per day, i.e. if you were to lie in bed all day and do nothing, this is the amount of calories your body would ‘burn’ just to function.

To work out our BMR, we use the following formula:

English BMR Formula
Women: BMR = 655 + ( 4.35 x weight in pounds ) + ( 4.7 x height in inches ) – ( 4.7 x age in years )
Men: BMR = 66 + ( 6.23 x weight in pounds ) + ( 12.7 x height in inches ) – ( 6.8 x age in year )

Metric BMR Formula
Women: BMR = 655 + ( 9.6 x weight in kilos ) + ( 1.8 x height in cm ) – ( 4.7 x age in years )
Men: BMR = 66 + ( 13.7 x weight in kilos ) + ( 5 x height in cm ) – ( 6.8 x age in years )

Let’s use an example.
I prefer to use the Metric system so let’s say there is a 40 year old woman weighing 60 kilos, who is 167cm tall.
BMR = 655 + (9.6 x 60) + (1.8 x 167) – (4.7 x 40) = 1343.6

In this example, her daily calorie intake would be 1343.6 Kcal at rest.

Now, I don’t know many people who lay in bed all day, so this figure alone isn’t enough, what we want to look at now is our daily energy expenditure. There is another formula called the Harris-benedict formula which gives us a greater and more accurate calorie amount:

Harris Benedict Formula

To determine your total daily calorie needs, multiply your BMR by the appropriate activity factor, as follows:
• If you are sedentary (little or no exercise) : Calorie-Calculation = BMR x 1.2
• If you are lightly active (light exercise/sports 1-3 days/week) : Calorie-Calculation = BMR x 1.375
• If you are moderately active (moderate exercise/sports 3-5 days/week) : Calorie-Calculation = BMR x 1.55
• If you are very active (hard exercise/sports 6-7 days a week) : Calorie-Calculation = BMR x 1.725
• If you are extra active (very hard exercise/sports & physical job or 2x training) : Calorie-Calculation = BMR x 1.9

With our above example, let’s say the woman works in an office and doesn’t exercise, we need to multiply her figure of 1343.6 x 1.2, giving a new figure of 1612.32Kcal.

So this woman would need 1612Kcal per day. If she is eating exactly 1612 Kcal a day, her weight should stay the same, any more than that she would put on weight and any less she would lose weight. Now if she were to follow the government guidelines of 2000Kcal a day, she would be gaining weight and most probably be pretty upset about it!

Why don’t you work out your daily calorie amount now, it may surprise you.

As with most things, this is the tip of the ice-berg. Our next post will explain what the different types of foods and the calories they give us and why certain ones are better for your fitness goals.