Weight loss boils down to just one thing – calories in vs. calories out. It doesn’t matter how you achieve that; some diet plans reduce calories by cutting out food groups, some by restricting eating times, some by resorting to a short list of approved foods. But the bottom line is that any diet that works does so by causing you to eat fewer calories than you burn. Some people do very well on plans that don’t directly require them to count calories – but many others find that the flexibility of being able to choose their own foods is easier and more effective, so they turn to calorie counting as their diet and maintenance plan.

Of course, the first question that people ask when starting to count calories is the obvious one: How many calories should I eat?

For years people have heard various figures; 1500 calories, 1200 calories, even 1000 calories. The general mindset seems to be “the fewer calories the better” – and this has come from the media, from friends, from books, and even from doctors. The fact, however, is that not everyone needs the same amount of calories and fewer is not always better. Do you really think that a 300 lb man should be eating the same number of calories as a 150 lb woman?  Of course not! So picking some number at random is not the healthiest or most effective way to go about this.

So how do you know how many calories to consume?

The long and complex way to go about it is to use the Harris-Benedict equation. The HB equation is pretty much the standard in determining an individual’s BMR (Basal Metabolic Rate) and their overall daily calorie burn (which are not the same thing). If you want to figure it out for yourself, the HB equation (which is different for men and for women) is this:

Men: 66 + (13.7 x weight in kilos) + (5 x height in centimetres) – (6.8 x age in years)
Women: 655 + (9.6 X weight in kilos) + (1.8 X height in cm) – (4.7 X age in years)

Using this calculation will give you your BMR – which is the number of calories you’d need to simply lie in bed and breathe.  You then multiply your BMR by your regular daily activity level to get the number of calories you’d need to maintain your current weight:

• If you are sedentary (little or no exercise): BMR x 1.2
• If you are lightly active (light exercise/sports 1-3 days/week):  BMR x 1.375
• If you are moderatetely active (moderate exercise/sports 3-5 days/week):  BMR x 1.55
• If you are very active (hard exercise/sports 6-7 days a week):  BMR x 1.725
• If you are extra active (very hard exercise/sports & physical job or 2x training):  BMR x 1.9

Most people will fall into the 2nd or 3rd range.  This number will be the number of calories you should consume to MAINTAIN your current weight.

Once you’ve figured out this number, you can subtract calories to begin losing weight.   How much should you subtract?  Ultimately that’s up to you, but the idea behind healthy, safe, and sustainable weight loss is to eat as many calories as you can, while still dropping enough to lose weight. The more calories you drop at one go, the faster you slow your metabolism, and the sooner your weight loss will hit a “stall” or “plateau”.  So ideally, reducing your calories between 20% and 30% is a good figure.

That’s a  lot of math, though, and can be confusing to a lot of people.  There’s a way to simplify this even more – a method that is remarkably consistent for men and women at all weights and heights.  That method is this:

Men:  Multiply your current weight by 12
Women:  Multiply your current weight by 10

So for example, if you’re a 250 lb man – eat 3000 calories.  If you’re a 170 lb woman – eat 1700 calories.  And so forth.

Looking for more?  There isn’t more.  That’s it.  Eat the number of calories that you get when you multiply your bodyweight as shown above.  For most people, that will provide a reasonable and safe level of calorie reduction – one that isn’t too extreme and produces results.

One more thing – keep in mind that all calorie estimates are just that:  ESTIMATES. Not every 170 lb woman burns the exact same amount of calories.  In fact each person will burn different amounts of calories each day – with variances of as much as 10% or more – depending on what they do from day to day.  So don’t freak out over 10 calories or 20 calories one way or another.  It’s the averages over the long term that count.

Next article we’ll talk about nutrients vs. calories.  While the bottom line of weight loss is calories in vs calories out … what you eat is as important as how much you eat, when it comes to being healthy as well as losing weight.