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BMR Calculator

Now that we defined BMR, let's see how we can use it to our advantage when it comes to losing weight.

Like figuring out your body fat, you can calculate your BMR in a variety of ways, use an online calculator to input your current weight, height and age or have it officially measured at a nutrition center. From what I've heard, the online calculator though it takes a generic approach, is fairly accurate, so that's what I used.

Plugging in my stats, I get the following figures:

My BMR is 1658

Now to determine my daily caloric needs I use the Harris Benedict Formula which multiplies my BMR by the appropriate activity factor:

• Sedentary (little or no exercise) = BMR x 1.2
• Lightly active (light exercise/sports 1-3 days/week) = BMR x 1.375
• Moderately active (moderate exercise/sports 3-5 days/week) = BMR x 1.55
• Very active (hard exercise/sports 6-7 days a week) = BMR x 1.725
• Extra active (very hard exercise/sports & physical job or 2x training) = BMR x 1.9

Now here is something else I recently learned, though I exercise quite a bit, if your job is one where you sit in a chair for about 8 hours a day and you drive 1-2 hours and when you get home spend most of the evening in bed, at computer desk or watching TV, you are considered sedentary. When I worked retail, I could call myself moderately active, as I spent 8 hours on my feet, walking up and down the store and hauling clothes and an hour a day walking to and from work.

An hour or so of exercise a few days a week does not make you an active person. But that's my theory. You can figure yourself accordingly if you feel active based on what you do.

Back to me

Sedentary (little or no exercise) = BMR x 1.2

1658 x 1.2 ='s a daily caloric needs of 1990 to maintain my current weight.

There are approximately 3500 calories in a pound of stored body fat. So, by creating a 3500-calorie deficit through diet, exercise or a combination of both, I'll lose one pound of body weight. (On average 75% of this is fat, 25% lean tissue) If I create a 7000 calorie deficit I will lose two pounds. The calorie deficit can be achieved either by calorie-restriction alone, or by a combination of fewer calories in (diet) and more calories out (exercise). This combination of diet and exercise is best for lasting weight loss. Sustained weight loss is difficult or impossible without increased regular exercise.

If I want to lose fat, a useful guideline is to lower my calorie intake by at least 500, but not more than 1000 below maintenance level. For people with only a small amount of weight to lose, 1000 calories will be too much of a deficit. Minimum calorie intake should never drop below 1200 calories per day for women or 1800 calories per day for men. Even these calorie levels are low.

Without factoring in exercise 1990 - 500 = 1490 daily calories to net me a 1lb loss. Here's where the numbers get tricky, say your daily caloric deficit fluctuates between 250-500, again not factoring in exercise, your deficit for 7 days will look like this:

M -200, T -175, W -500, Th -500, F -250, S -400 S -350

For a grand total of 2375 calories a .7lb loss (2375 / 3500), which may not even show up on the scale. Let's go a few more days into the following week shall we?

M -350, T -280, W -500

Well what do we have here? A 3505 deficit and your 1lb loss will show up, not on the 7th day, as is widely touted, but on the 9th day. Unless you are regimented and know your stats to a tee, I suspect most of us lose weight over a period of 7-11 days.

Back to me

Let's fast forward a few weeks, your resident fat fighter has shed 10lbs, hey it's not impossible, last time I blurted my stats on this site I was 196, today I'm 192 thankyouverymuch…waitaminute…::rubs eyes::…I. Lost. Weight. Boo-Yah!

At 186, my BMR is now 1615. Granted it's not a huge drop from 1658, but just enough to see at a lesser weight, I need less calories, 1938, to maintain my weight. If I continue to consume the same calories as I did before that netted my loss, 1490, I'll either stall or gain a bit.

To remedy that, I can do a few things, cut my calories down even more to 1438 (1615x1.2 = 1938-500 = 1438), but I'll eventually stall out at 1200, besides who really wants to eat less food? Or I can *gasp* work out, harder.

Say during 194-184lbs I walked on the treadmill at 3mph, from 184-174lbs I will need to mix it up, either start running at that same speed, or increase the incline to 1-2%. The time can stay the same, even the speed can stay the same, but the intensity must change.

Keep in mind, this is all very bare bones. I didn't talk about carb bloating, or dehydration or lifting weights or muscle mass or fluctuations or a host of other things that can make it frustrating.

If you just look at it in a 1 + 1 = 2 approach:

1. Figure out your BMR
2. Multiply it by your current activity level (be honest)
3. Minus 250-500 calories
4. Eat the reduced amount of calories and however long you guesstimate you've burned 3500, you'll net your 1lb loss. Speed things up by doing some physical activity, but try to keep it realistic by losing no more than 2lbs per weigh in.
5. Every 10-15lbs, spot check your BMR again, especially if you feel a plateau kicking in, and revise your calories.

I know it's a lot of info to absorb, I tried to make it as simple as possible, but if you have any questions or even objections, definitely post them, it helps me see if my theories make sense.