Recently I have had some talks with some clients that believe that extreme calorie restriction is the way to lose weight and “tone up”. Extreme calorie restriction can be very dangerous. The only time I would even condone something like that would be if the person was under the care of a doctor who prescribed the extreme calorie restriction to them. The following are some facts and insights into how extreme calorie restriction can affect the body and how many calories are really needed to lose weight.
Extreme calorie restriction causes your body to go into starvation mode. This is the worst case scenario for trying to lose fat. In starvation mode your body actually tries to hold onto fat because it is a denser source of energy. Instead of burning the fat, your body will find energy from other sources before it goes after the fat stores. It will take energy that is being used to build muscle (you know one of the goals of exercising) and redirect it to mechanisms in the body it deems more important. It will continue taking energy from your lean body mass before the fat. That means weaker bones, weaker organs, and weaker ligaments and tendons. Can you guess what might happen next? Well, since you now have no muscle, weak bones, and weak connective tissues you are more prone to energy. You may actually even get frustrated due to the fact that you cannot lift as heavy as you once could because you now have less muscle. It’s easy to see why extreme calorie restriction can be damaging.
Now if you are eating enough calories for your body to maintain its lean body mass and continue to build muscle, your body will have an increased metabolism. Remember an increase in metabolism means an increase in basal metabolic rate. Which means you are burning more calories throughout the day. See below to determine your Basal Metabolic Rate.
According to Dr. Rosenbaum, MD of Medscape.com if you lose weight as fat you will actually lose fewer pounds than you would for the same number of calories of muscle. Remember muscle weighs twice as much as fat. That means you may notice a change in the fitting of clothes before you notice a change in your weight on the scale.
So how do you know many calories you should be taking in? And how do you track them?
My favorite way is the MyFitnessPal app. It allows me and my clients to friend each other and I can check in on what they are eating and they can see what I am eating. Best of all it will do all of the above calculations for you. If you download the app and start using it search for FullTorqueFitness and I would love to follow along and encourage you on your journey.
If you want to do the calculations yourself, then here you go.
First lets define Basal Metabolic Rate, it’s the amount of calories is takes your body to keep going if you were at complete rest all day.
Now how do you calculate that number?
Male: BMR = 10×weight + 6.25×height - 5×age + 5
Female: BMR = 10×weight + 6.25×height - 5×age – 161
I know that equation can be a little intimidating, but it gets better. For this equation to work you have to make sure your weight is in kilograms and height is in centimeters.
To convert lbs to kg you take your weight and divide by 2.2, so 165 lbs / 2.2 = 75 kg
To convert height in inches to cm you have to multiply by 2.54, so a 5’10” person is (12x5)+10= 70 inches x 2.54 = 177.8 cm
So for a 33 year old male following the equation above –
10x75 + 6.25x177.8 – 5x33 + 5 = 1701.25 calories needed per day
But remember that is if he sits in a chair all day. For every little bit of exercise or movement he does more calories have to be added. To do this you have to multiply the above number by the following factors.
1.200 = sedentary (little or no exercise)
1.375 = lightly active (light exercise/sports 1-3 days/week, approx. 590 Cal/day)
1.550 = moderately active (moderate exercise/sports 3-5 days/week, approx. 870 Cal/day)
1.725 = very active (hard exercise/sports 6-7 days a week, approx. 1150 Cal/day)
1.900 = extra active (very hard exercise/sports and physical job, approx. 1580 Cal/day)
This 33 year old male is moderately active, so you need to take his 1701.25 calories and multiply by 1.550.
1701.25 x 1.550 = 2636.94 calories
That is his daily caloric need, if he plans on maintaining his weight.
He would like to lose 5 lbs. The healthy way to lose weight is at most 2 lbs per week. Since he wants to lose only a few lbs I would say to make it easiest on him to lose between .5 and 1 lb per week.
A single lb is equal to 3500 calories. To lose 1 lb per week that is a 500 calorie deficit he needs to have each day.
Meaning he needs to go from 2636.94 calories per day to 2136.94 calories per day to lose 1 lb per week.
Now let’s look at a 24 year old female. She is 5’4”, weighs 155 lbs, and is lightly active.
Convert weight to kg 155 lbs / 2.2 = 70.45 kg
Convert height to cm 5’4” = (5x12) + 4 = 64 inches * 2.54 = 162.56
Use the female equation 10×70.45+ 6.25×162.56 - 5×24 – 161 = 1439.5
Add in activity level 1439.5 x 1.375 = 1979.31 calories per day.
If we tell her to lose 2 lbs per week that is a 1000 calorie deficit each day, meaning she needs only 979.31 calories each day.
Here is where I feel we have a conundrum.
According to the American College of Sports Medicine, no one should have that few of calories per day. The recommend that women have no less than 1200 calories per day and men have no less than 1800 calories. I myself and even more a proponent of no less than 1500 calories per day.
So how do we fix this? This is where exercise comes in. Light activity means very little exercise, most like a couple of walks a week, maybe a 30 minute trip to the gym where she does a few machines, but doesn’t truly push herself.
Adding in a real exercise regimen of 3 or more days per week for about an hour at a time where you put in real work would change her calculations.
New activity level 1439.5 x 1.550 = 2231.23 calories.
Meaning she can now take 1000 calories off per day and stay above that 1200 calorie mark.
Now go out there and lose that weight!