When you are starting a weight loss diet, you know to eat well and healthy foods, but how do you work out how many calories you should eat?
We know that creating a calorie deficit will help us lose weight, but how much should be reducing our intake by for weight loss?
If we are not careful, we can over-reduce our calories and when you do that, you risk not losing weight, because your body is in starvation mode and holds on to fat and you could find yourself being lethargic and unwell, as you don’t have enough fuel to keep your body functioning optimally.
So how can you work out the right calorie balance for you on your weight loss diet, if you’re trying to lose a few lbs?
As a rule, we know that general NHS guidance states that women should eat about 2000 calories a day and men should eat 2500 to maintain weight.
So in theory, we should eat less than this to lose weight. But how much less?
This will be really dependent on each person, but the good news is, you can work it out and get a good idea of how many calories you should eat to lose weight.
How to work out how many calories you should eat.
To do this you need to work out your Basal Metabolic Rate (BMR) – basically the number of calories your body burns just by functioning.
We do this using the Harris-Benedict Equation, as below.
Please note – these calculations are subject to change or differences and are not meant to be 100% accurate.
- Women BMR = (10 X weight in kg) + (6.25 x height in cm) – (5 x age in yrs) + 161
- Men BMR = (10 X weight in kg) + (6.25 x height in cm) – (5 x age in yrs) + 5
We know this could look a little complex, so here is an example using Susan, who is 36, she’s 167cm (about 5ft6) and weighs 81kg (about 12 and a half stone).
10 x 81 + 6.25 x 167 – 5 x 36 + 161
810 + 1043.75 – 180 + 161
Susan’s BMR = 1834.75
So, as a minimum, Susan should be eating 1834 calories per day to sustain her energy levels and standard of living as that is how many calories her body burns, roughly, just by simply existing!
But it doesn’t end there, we also need to factor in movement and activity, and this helps us calculate our Total Daily Energy Expenditure (TDEE).
Your TDEE is the total number of calories you burn in a given day by simply moving around, doing things like taking the stairs, hoovering, walking to the car and any exercise you do.
To calculate your TDEE, you simply multiply your BMR number, in Susan’s case, 1902, by how active you are:
- Sedentary (little to no exercise + work a desk job) = 1.2
- Lightly Active (light exercise 1-3 days / week) = 1.375
- Moderately Active (moderate exercise 3-5 days / week) = 1.55
- Very Active (heavy exercise 6-7 days / week) = 1.725
- Extremely Active (very heavy exercise, hard labour job, training 2x / day) = 1.9
In Susan’s case, she has a sedentary desk job, but does attend a few Zumba classes a week, so we are going to multiply her BMR by the lightly active category of 1.375.
1834 x 1.375
Susan’s TDEE = 2521.75
So this equation shows us that Susan needs to consume roughly 2521 calories per day and she should MAINTAIN her weight.
But what if we want to lose weight?
Typically, if you want to lose weight, you would look to reduce your TDEE number by 20% and this should see you losing a sustainable 1-2lbs per week.
So if Susan wanted to lose weight:
20% of Susan’s TDEE: 0.20 x 2615 = 504
Susan’s daily calorie intake for weight loss: 2017 calories
Using a 504-calorie deficit, Susan would lose just over 1lb per week, as we know that 1lb of weight loss = 3,500 calorie deficit.
If you’ve been watching your calories, how many have you been having? Have you ever checked your TDEE numbers to see how many you should eat?
Try our calculation today and see how you can lose weight the healthy way!
Or, why not try an online TDEE Calculator? Try this FREE one!
If you want more help with your calorie consumption, or what to eat, please do get in contact with us.