As I mentioned in my last post about the three age-related weight gain challenges, the key to managing your weight is to balance energy input with your energy expenditure.
In this post we will take a look at the energy expenditure side of this equation. Once we understand approximately how many calories you are burning we can compare this to the number of calories you are consuming. I have included a simple calorie expenditure calculator below if you don’t feel like doing the math.
Resting Metabolic Rate
Your body requires energy just to keep you alive. So even when you are resting you are burning calories. This is known as the resting metabolic rate, RMR, or Resting Energy Expenditure, REE. There are many factors which affect your RMR, but the main ones are age, gender, height and weight. There are a number of formulas that can be used to estimate your RMR from these factors.
Mifflin – St Jeor Equation
The Harris – Benedict equation (1919) used to be the standard equation for calculating minimum calorie expenditure, but the more recent Mifflin – St Jeor equation (1990) is now considered to be the most accurate and is a better match for today’s typical diet and body composition. So we will use the Mifflin equation below.
+ 5 if you are male
-161 if you are female
Given that you are likely doing a bit more than lying in bed all day, we will also want to factor in your activity level. If you live a typically sedentary lifestyle we multiply the REE number by 1.2, if on the other hand you are extremely active we multiple the number by 1.9. The calorie expenditure calulator below shows a range of activity levels, by judging where you are on this scale you can estimate your daily calorie expenditure.
Maintaining Your Current Weight
If you plug your current weight into the calorie expenditure calculator below then you will discover how many calories you need to consume to maintain your current weight. Consume more than that and you will get heavier, consume less than that and you will get lighter. Yes the mechanics of weight management really are that simple.
Reaching Your Target Rate
Now here’s the magic – plug in your target weight to the calorie expenditure calculator below and you will find out how many calories you should consume in order to reach your target weight. The trick here is not to just go on a diet, but to make a permanent change to your lifestyle – I will talk more about this in future posts.