Tel's Tales #1: Energy Costs
Posted by Concept2 News on the 27th of December 2003
Many people try to follow a calorie-controlled diet. To lose weight, gain weight or maintain weight you must have an idea of your daily calorie requirement. To lose weight, the calories taken in from food and drink must be less than the calories expended. To gain weight, the calories taken in from food and drink must be more than the calories expended. Finally, to maintain weight, there has to be a balance between the calories consumed and the calories expended. Whether you are a lightweight competitor, or overweight and trying to reduce, knowing your daily energy costs is an important part of your weight management programme.Energy costs can be divided into three main groups, the basal metabolic rate (BMR), which is solely the cost of running your life support system, heart, lungs, digestion etc. Daily expenditure, which is what you do when awake up and about, and finally the energy costs of exercise.To find your BMR, go to http://www.therowingcompany.com/training/bmr.php there you will find a simple way to determine your own BMR and this is the first step.If we take, as an example, a 22 year old female who weighs 65 kg. From the website we see that her BMR is 1,449 kCals. To estimate your average daily expenditure, you need to take your BMR and multiply it by a factor, which is determined by your activity level. If we assume that our example is very active during the day, then the factor is 2.0 so the BMR is doubled to 2,898 kCals to give the estimated daily expenditure.If she follows this with a day of relaxation where she is mainly sedentary, mostly seated or just standing then you multiply the BMR by a factor of 1.4 so her energy expenditure falls to 2,028 kCals.On another day, she is moderately active, regular brisk walking or manual work, then the factor is 1.7 and her energy cost rises to 2,463 kCals.To determine the cost of training we have to find the hourly BMR, which is done by simply dividing your BMR by 24. If we use the BMR in the example then the hourly BMR is 1449/24=60.3For the different rowing intensities there is a Physical Activity Ratio (PAR) and to find the energy costs of training the formula is, hourly BMR x PAR x duration.For UT2 the PAR is 3.5 and if our example rows for 1 hour at UT2 then her energy costs for the exercise is 60.3 x 3.5 x 1= 211 kCals.The PAR for the other training bands is UT1=7.0. AT =8.5 and TR=12.0.Continuing to use our example, the energy cost for some typical training sessions are. 30 minutes UT1=60.3 x 7 x 0.5 = 211 kCals.24 minutes AT= 60.3 x 8.5 x 0.4 = 205 kCals12 minutes TR = 60.3 x 12 x 0.2 = 145 kCals. If the young woman carries out a 30 minute UT1 session on an active day then on that day the total energy costs is 3106 kCals.To embark on a calorie control diet with no idea of your daily calorie requirement is not only a waste of time it can present a health risk. Many diets I have seen seem to pluck a total daily calorie requirement out of the air and it is not unusual to see a figure of 1,000 kCalories for woman. I have used an example of a small woman and two things are apparent, the difference from day to day and that her BMR is almost 1,500 kCalories.Although in order to lose weight it is necessary to take in fewer calories than you expend, it should not fall below your BMR. If it does then your body goes into Famine mode. In this condition it is not necessarily fat that is lost faster but lean body mass and water, and the metabolism slows down to balance the reduced calorie intake. The consequence is loss of strength, lack of energy, mood swings, tiredness, sluggishness and not to mention feeling bloody hungry. Your immune system will also be affected and you will become vulnerable to infection.The process outline here is a guide to your energy output and is a good place to start if you are interested in weight management. Of course the other aspect is knowing the calorie balance. Energy will be provided by three food groups, carbohydrates, protein and fats. The relative balance between these groups is 65% carbohydrates, 12% protein and 23% fats. Going back to our example on the day where the energy expenditure is 3,106 kCals then the estimated dietary requirement is 470gs of carbohydrate, 80gs of fat and 87gs of protein. This is because each gram of carbohydrate and protein will provide 4.3 kCalories while fat will provide 9 kCalories. If all this maths is just too much then there is an alternative, have a full nutritional analysis from an expert nutritionist. This will take into account all of your individual energy input and expenditure from which it is possible to assess your individual nutritional status and needs. This can cost in the region of 100 pounds but for the first 20 people who respond requesting the analysis then we will arrange for it to be done for 25 pounds. If you are interested in this, drop me an email at tels-tales@therowingcompany.com.