Last week we worked through the process
of understanding the metabolism and its role in keeping the body healthy. We came to an understanding of Basal
Metabolic Rate; its meaning and the process of calculating the amount of
calories needed to meet this demand.
However, there are two other factors that need to be considered when
determining the body’s nutritional needs: the amount of body fat present and
work-related physical activity and/or exercise.
Over the years I have found that the
formulas used to arrive at BMR result in an overestimation of caloric needs in
overweight and obese people. The reality
of the human body is that body fat slows down metabolic rate. Two people may be of the same gender, age,
height, and weight but if one person’s weight is comprised of substantially
more body fat than the other person, this overweight person will have a
significantly slower metabolism, and thus, burn fewer calories. I have found that using the following
guidelines to alter the BMR calculation results in a more accurate number of
calories needed for those that are overweight or obese.
·
If your body fat is between 20-29% and/or
you have 30lbs-100lbs to lose and your BMI is 25-27 take the BMR
that has been calculated and multiply your calculated BMR by 0.75. This
is a more accurate Adjusted BMR.
So:
BMR x 0.75 = Overweight Adjusted BMR
·
OR, if your body fat is higher than 30%
and/or you have more than 100lbs to lose or your BMI is above 27 then multiply
your calculated BMR by 0.60. This is a more accurate Adjusted
BMR. So:
BMR x 0.60
= Obese adjusted BMR
Going, back to the BMR calculations in
the examples from last week, we will now walk through this process.
•
Overweight
Female BMR = 1563 calories x 0.75 = 1172 calories
o
This is
a difference of 391 calories
•
Obese
Male BMR = 1918 calories x 0.60 =1150 calories
o
This is
a difference of 768 calories
It is important to note that these
adjustments to the BMR reflect the amount of calories needed for days of little
or no physical activity or exercise.
This is a crucial step in properly identifying the correct number of
calories needed by an overweight or obese person. Make sure to correctly identify which
category, if any, you fall into too.
Skipping this step will result in consuming too many calories and
inhibiting fat loss. If you do not fall
into either of the two classifications, as I have given them, then keep the
original BMR calculation. From this
point we will now begin factoring in physical activity and exercise. Before beginning the process of accounting
for physical activity and exercise the two must be clearly defined so that the
difference can be understood. Everyone
engages in physical activity but few people engage in exercise.
Physical activity- any form of bodily movement that prevents the body from being motionless
or sedentary. This can include physical activity related to
work or employment.
Exercise- is any rhythmic
physical activity purposely done for a defined period of time and in specific patterns of movement for the purpose
of improving coordinated movement, physical strength, endurance,
and BMR.
There are five classifications of people: Sedentary, Lightly active,
moderately active, very active, and extremely active. The vast majority of people will fit into
either the sedentary or lightly active category. Over-estimation of physical activity levels
is a common problem when identifying the appropriate classification; follow the
guidelines as closely as possible to properly classify yourself.
A sedentary person spends most of their
day at a desk, or computer, or in front of a TV, and rarely leaves home except
to go to work. This person may do
household chores such as washing the dishes, laundry, vacuuming. However, this person does NOT engage
in exercise or physical activity such as yard work. A sedentary person does NOT need
to increase calorie intake. An increase in calories will result in
an increase in body fat for this
person.
A lightly active person has a job where the majority of time is
spent sitting at a desk, and will perform physical chores or light exercise for
up to four hours per week. Examples would include mowing the lawn (with a push mower), painting,
pulling weeds, raking leaves, walking the dog, yoga. This person multiplies
BMR by 1.3 to maintain body weight.
A moderately active person has job that
keeps them on their feet, but is not labor intensive, such as a teacher, nurse, or restaurant employee
or exercises a total of 3-4 hours per
week performing weight training and exercises such as jogging or biking 2-3
times per week but does not spend more than a total of 4 hours per week
exercising. Or this person could play
organized sports with practices and competitions meeting the weekly time
commitment. To calculate the caloric
needs of this person multiply BMR by 1.4 to maintain body weight.
A very active person has a labor intensive job, such
as a construction worker or exercises 6-8 hours per week and would follow a
program that includes cardiovascular and strength training: running more than 20
miles/week or biking more than 40 miles, swimming more than 3 hours and
weightlifting 3-4 times per week. This
person will multiply BMR by 1.6 to maintain body weight.
An extremely active person is someone
exercises more than 12 hours per week, regularly competes in organized
sports and does weight training 4 or more times per week, or, runs half
or full marathons, iron mans, or competes as a college, Olympic, or
professional athlete. This person
multiplies BMR by 1.8 to maintain body weight.
Keep in mind that up to this point the number of
calories being discussed is still only about maintaining the current condition
of the body, while factoring in physical activity and exercise. This category has been correctly identified
and the calculations completed, the focus can shift to changing caloric intake
for fat loss or muscle gain.
It is
important to remember that changing the body either for losing or gaining
weight requires an appropriate balance between the amount of calories consumed
through food and calories expended due to BMR and physical activity or
exercise. This balance is easier to
achieve, particularly when trying to lose weight, by understanding that one
pound of body fat stores roughly 3500 calories worth of energy. There are seven days in a week: dividing 3500
by seven results in 500. To lose one
pound of fat per week the body must use 500 calories per day in energy more
than it consumes through nutrition. At
least, that is what the math says.
Unfortunately,
the body does not work exactly the way the math does. Now, the straight math will work for
sedentary people who have no intention of exercising. But, if you already exercise, simply creating
a calorie deficit of 500 calories will not work. When a person is participating in regular
exercise program simply eating 500 calories per day less than needed or, by
using exercise, burning 500 calories per day more than needed creates too large
of a calorie deficit for the body to properly recover from the strain of the
exercise. A 500 calorie deficit created
this way will prevent the body from keeping and adding to its lean muscle
mass. A loss of muscle mass in this
scenario will slow down the body’s metabolism, making it easier to eat more
calories than necessary. Over time, this
will result in an increase in body fat.
Welcome to discouraging cycle of exercising and decreasing your health.
The 500
calories is an important number but it must be achieved through a combination
of diet and exercise to ensure effectiveness.
I recommend reducing the amount of calories consumed by 200-300 calories
per day while burning an additional 200-300 calories through physical activity
and exercise. Sticking to this process
will produce a weight loss of 1-2lbs per week.
Now, suppose
this a man would want to add muscle mass to his body. To accomplish this he would have to consume
more calories than burning. This can be
done without adding body fat as a part of the process. Part of the reason most people do not do this
because they consume far too many calories when trying to add lean muscle
mass. For most people, to add lean
muscle mass without adding body fat only requires an additional 250 calories
per day. So if this man needs 2685
calories to preserve his current body weight and composition than he would only
require 2935 calories per day to add muscle mass to his body.
As you can see
this can be a challenging process to learn, be patient and stick with it. Success comes to those who stay disciplined
and focused.
Stay strong!
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