Calories: How many to eat and how many burnt?
Many health and fitness programs base their systems on two pieces of critical information:
1) How many calories did you eat today?
2) How many calories did you burn?
Assuming the individual has a goal (for example to lose one pound every week), the program takes this into account and gives the individual a limit to the number of calories they can eat. However, when someone works out, they burn calories, which enables them to eat more if they chose to without surpassing their caloric limit. Therefore, calculating how many calories are burnt during a period of physcial activity is quite important to the success of health and fitness programs. Below is the process LiveStrong and many other companies use to calculate how many calories were burnt in an activity:
step 1- covert weight (lbs) to kg by dividing that number by 2.2 (i.e. 150/2.2= 68.18)
step 2- look up MET value of the activity performed on
(i.e. running MET value= 7.5)- "MET: metabolic equivalent. 1 MET is defined as the energy to lie/sit quietly. It is equivalent to a metabolic rate of consuming 3.5 mL O2/kg/minute"
step 3- multiply MET value by weight in kg (i.e. 68.18 X 7.5 = 511.35)
step 4- multiply answer from step 3 by the time you worked out for (in hours) (i.e. 75 mins= 1.25 hours)
511.35 X 1.25 = 639.19 calories burnt
The main issue with this formula is that is does not acknowlege the intensity level at which you perform the activity. My brother and I could run for the same amount of time but it is likely I might take a few more breaks than he does and will be a bit slower, but that is not accounted for in the formula. Therefore, in order to improve this system, mathematicians around the world should attempt to create a new formula that recognizes the exertion of energy during the activity, because that factor plays a significant role in the amount of calories burnt.
Livestrong has also shared their formula that they use to guide members on how many calories to consume each day in order to reach health goals:
"step 1:convert weight to kilograms by multiplying weight in pounds by 0.4536
step 2: measure height in inches- convert to cm by multiplying inches by 2.54-
step 3: resting energy expenditure:
Calculate your resting energy expenditure--the calories you burn per day while resting--using the following formula if you are female:(10 × weight in kilograms) + (6.25 × height in centimeters) - (5 × age in years) - 161;or this formula if you are male:(10 × weight in kilograms) + (6.25 × height in centimeters) - (5 × age in years) + 5.
Step 4- multiply resting energy expenditure by physical activity factor-
If you exercise less than 3 times a week- use 1.12 (F) or 1.11 (M)
3-5 times a week- use 1.27 (F) or 1.25 (M)
6-7 times a week- use 1.45 (F) or 1.48 (M)
step 5- subtract 500-1000 calories from total energy expenditure if you want to loose 1-2 lbs a week
tips- eat between 45-65 percent of cals from carbs, 20-35% from fatty food sources, 10-35 percent from protein- according to US depart of Health and human services"
It is clear that a wide range of mathematical techniques are used when approaching matters having to do with health and fitness. The formula presented by Livestrong above is just one example, as many other companies (WeightWatchers, Insanity, etc.) present unique but similar formulas. Here we can see that math is the fundamental difference that stands between so many companies in an industry that has experienced robust growth in recent years. Not only is math being used to create ideas, businesses, and profits, but more importantly math is being used to help individuals all over the country and world, work towards a healthier and happier version of themselves because when people see a mathematical equation sitting in front of them, claiming it is the solution to their problems, people have a hard time saying no to numbers.