Run a 1,000 Calorie a Day Deficit

Ok, not really.  Keep reading and you’ll understand why.  One of the most frequent questions I get from people is a concern that they are taking in too many  calories to lose weight while doing P90X.  They just cannot see how they could possibly lose weight while taking in the number of calories recommended by the plan.  This is particularly true with people that have been on some form of low calorie diet, like Weight Watchers.  Running a calorie deficit is one way to lose weight, but cut too many and you’ll sabotage your results.

It is really important to understand what we mean by a calorie deficit.  A calorie deficit is the difference between what you burn and what you eat. If you eat 2,000 calories and burn 2,500 today, your calorie deficit is 500 and your “net” calorie number is 1,500. This is important because the size of your calorie deficit will help determine how much weight you lose each week. Creating a calorie deficit forces your body to use stored energy which will cause the weight loss.  To lose one pound in a week, you need to create a calorie deficit of 3,500 calories during the week. Since a week has seven days, you divide 3,500 calories by seven and get 500.  Too many people take this advice to the extreme, and try to run a bigger deficit to lose more weight.  We’ll examine why this is a bad idea, particularly while doing P90X, below.

The primary reason that taking in far too few calories is a bad idea, is that it isn’t sustainable.  For most people, this means depriving themselves of food.  At some point, that “willpower” is going to cave and the calories are going to go back up.  When they do, the body is ill equipped to deal with the situation since it has been under fueled for some period of time.  The result is a less efficient metabolism that causes your body to store more fat.  What works, and what is sustainable, is a sensible calorie deficit comprised of a healthy diet combined with regular exercise.

Here are a few things to understand with the P90X Nutrition Guide:

  1. Get the Right Number – Keep in mind that the P90X Nutrition Guide adds 600 calories to your daily total.  It does so to avoid running a deficit, because the plan isn’t designed specifically for weight loss.  The 600 is a rough approximation of how many calories the average person burns doing a P90X workout.  The truth is that women usually burn less than 600 calories doing P90X, so this is somewhat imprecise.  If you have a heart rate monitor that gives you calorie expendature, this is an easy number to dial in.  You can also just take out the 600 from the equation, and then you’ll be in a deficit situation.
  2. Focus on Net Calories -  Don’t focus on the total amount of calories you are taking in.  Look at how many you’ve burned as well.  Let’s say you’ve taken in 2,000 calories in a given day and you burned 500 doing Plyometrics X.  Your net is 1,500 for that day.  That’s what your body has left to use, so don’t focus on 2,000, focus on 1,500, since that’s what your body has left to run your essential bodily functions and generally power your body through the day.
  3. Understand RMR and BMR – Step one in calculating your calories with the P90X Nutrition Guide is calculating your Resting Metabolic Rate (RMR).  RMR and BMR (Basal Metabolic Rate) are designed to provide the amount of calories your body would use if you did nothing but rest all day (no exercise).  The P90X equation isn’t that precise, because it doesn’t take into account height or age and only relies on weight.  You can find a better RMR calculator here: http://www.shapeup.org/interactive/rmr1.php.  Calc your RMR and use that number in the spreadsheet you’ll find in our breakdown of the P90X Nutrition Guide.  BMR is just another way to calculate this, but it is a good number to understand if you are struggling with this issue.  Here is a good BMR calculator: http://www.bmi-calculator.net/bmr-calculator/.  “BMR, is the minimum calorific requirement needed to sustain life in a resting individual. It can be looked at as being the amount of energy (measured in calories) expended by the body to remain in bed asleep all day!” Source: http://www.shapefit.com/basal-metabolic-rate.html.

All too often people contact me proposing a calorie intake that is at or below their RMR or BMR.  Again, this is usually in response to previous diet plans that do not require exercise or take into account the calories net of exercise.  Let’s assume your BMR is 1,500.  If you take in 1,500 calories, and burn 500 doing P90X, your net after P90X is only 1,000.  Then take into account your daily activity.  If you have an active job or chase kids around all day, you are burning even more calories, driving your net even lower.  When you understand what RMR and BMR are, you see why it is important not to go below that number.  It is extremely unhealthy and overtime can cause your body to actually store fat as it attempts to protect itself against what it views as starvation.

So what? Won’t I just lose more weight if I cut my calories below my BMR?  Maybe, and maybe not, but it won’t be healthy.  Here is a quote:

Calorie deficit thresholds: How low is too low?
It is well known that cutting calories too much slows down the metabolic rate, decreases thyroid output and causes loss of lean mass, so the question is how much of a deficit do you need? There definitely seems to be a specific cutoff or threshold where further reductions in calories will have detrimental effects. The most common guideline for calorie deficits for fat loss is to reduce your calories by at least 500, but not more than 1000 below your maintenance level. For some, especially lighter people, 1000 calories may be too much of a deficit. The American College of Sports Medicine (ACSM) recommends that calorie levels never drop below 1200 calories per day for women or 1800 per day for men. Even these calorie levels are extremely low. A more individualized way to determine the safe calorie deficit would be to account for one’s bodyweight or TDEE. Reducing calories by 15-20% below TDEE is a good place to start. A larger deficit may be necessary in some cases, but the best approach would be to keep the calorie deficit through diet small while increasing activity level.

Note that this quote is talking about net calories, not gross calories.

Putting it all together.  So, now that you have the info how do you make it work?  If you are doing P90X and want to lose weight, the easiest thing to do is just take the 600 calories out of the equation.  For most people, this works.  If you want to get really precise about it, then you can use the calculators above to calculate your RMR and/or BMR and use this number in Step 1.  If you want to lose weight, take out the 600 calories that are added in.  That should give you a pretty good idea of what your gross calories will be.  You then need to understand your net calories, and you can do that by calculating the number of calories you burn working out.  Again, if your gross is 2,000 and you burn 500, then your net is around 1,500 (not including your daily activity, which you should take into account – a construction worker needs more calories than a computer programmer).  Another thought, is to calculate your calories using the Insanity Calorie Calculator, which uses the Harris-Benedict Equation to calculate BMR and has built in adjustments for activity levels.  In addition, you can CONTACT ME.  I’m always happy to help people calculate their calories and arrive at a number that works for them.  We Coach people for free and are always willing to take on more clients.  More info on that HERE.

One final note. This article only talks about calories.  What you eat is just as important as how much to your overall health.  You can lose weight by eating exclusively McDonald’s if you get the calorie deficit right.  That doesn’t mean it is health or sustainable.  I strongly encourage you to explore around the site and learn more about healthy eating.  Eating well will accelerate your weight loss and promote a healthy way of life.  That’s what works over the long haul.

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