Losing Weight – Setting your Calorie Deficit

by GReeves on March 24, 2011

Losing Weight – Setting your Calorie Deficit


If you are trying to lose some excess body fat quickly before beginning serious training for an event, you should aim to consume 300-500 fewer calories per day than your body needs to maintain its current weight. This deficit is sufficient to yield steady fat loss but will not sabotage your workouts. Here is how to determine exactly how many calories to eat:


1)    Calculate calories burned during exercise. The easiest way to track your calories burned during exercise is by wearing a heart rate monitor. However, if you do not have a HR monitor, you can approximate your calories burned during your workout as follows: add up your total number of hours you train in a typical week and divide that number by seven to yield the average number of hours you train daily. For example, let’s say that you train 10 hours in a week on average, this computes to (10/7=) 1.4 hours per day. Next, multiply this number by your body weight in pounds and the average number of calories you burn per hour of training. The average number of calories you burn per hour of training is influenced by your speed. Based upon a slower/easy effort use 4 calories per pound per hour/use 5 for moderate effort and 6 for harder efforts. The result of this calculation is the average number of calories you burn through activity daily. For example, suppose you train 1.4 hours per day, weigh 150 lbs and have an average speed. In this scenario, you burn roughly (1.4x150x5=)1050 calories per day in workouts.

2)    Calculate calories burned outside of exercise – You can visit BMRCalulator.org and enter the information requested to get an estimate of your basal metabolic rate (BMR), or the number of calories your body burns per at rest. Take this number and divide it by 24, then multiply the number of hours per day that you do not spending working out. For example, suppose your calculated BMR is 1608 calories per day. We know that you workout 1.4 hours per day, which means there are 22.6 hours of the day when you are not working out. In this case, your adjusted BMR is (1608/24×22.6=) 1514 calories. Your BMR is only an accurate representation of the number of calories you burn outside of exercise if you sleep all day. To adjust your BMR to account for non exercise activity in your day, multiply it by the appropriate factor: activity level – nonphysical job & lifestyle (most fit in this category) 1.15 / nonphysical job & somewhat active lifestyle, 1.2 / physical job & active lifestyle, 1.3. If you have a nonphysical job and there isn’t a lot of physical activity in your day outside of workouts, then your total daily calorie burn outside of workouts is approximately (1514×1.15=) 1741 calories.

3)    Add your non-exercise and exercise calorie totals – To determine the total number of calories you burn daily, add together your average daily exercise calories burned and your calories burned outside of exercise, in this example, the sum is (1741+1050=) 2791 calories. This number also represents the total number of calories you would need to consume daily to maintain your current weight.

4)     Subtract your target calorie deficit from your weight maintenance calorie target – The number of calories you should aim to consume daily during a weight-loss is equal to the number of calories you would need to eat daily to maintain your current weight minus your chosen calorie deficit. Remember, the appropriate deficit range is 300-500 calories. Let’s say you choose 400 calories then you should aim to eat 2391 calories (2791-400) per day during your weight-loss.

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{ 2 comments… read them below or add one }

Peter K March 31, 2011 at 4:48 pm

Thanks for this info.  I just started counted calories myself and it really works to loose weight.  My question has to do with how much to eat after a long run / race.  Say I run for 4 hours and burn something like 3500 calories?  What sort of calorie goal should I use that day?  Is it ok to eat 5000 calories that day?  Or should I just stick to the daily calorie goal that I set for the week.  Any advise would be much appreciated!


GReeves April 3, 2011 at 6:51 pm

Peter – in response to your question, if your goal is to continually lose weight after workouts and racing, you should set a goal to eat 500 less calories per day based upon your total calories burned for the day. please refer to one of my posts that helps you calculate your calories burned that is not specific to your workout – meaning, calories burned for every day living/breathing/daily life. once you calculate your calories burned for every day living then add to your calories burned specifc for the workout of the day. also, please take note in my previously noted blog not to double dip – meaning not to count your every day caloric burned in 24 hours and add your 4 hours. this will make more sense if you read my blog.

lastly, set your calories per day specific to your workouts not per week that way you make sure to eat only what you need for the day. make sense?

please let me know if this makes sense or if you need more detail/info. we can also have a quick call if it helps as well.


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