Nutritional calculation for daily calories
I was exploring Sparkpeople and came across a very interesting article on how they calculate your daily caloric intake. I was intrigued so I decided to go through the math myself. Why? Because I love match and sometimes I feel like I am not doing the best that I could in terms of weight loss; it seems like such a slow process. Why? Because I get hungry after dinner and snack – this is a recent realization! – and it is likely sabotaging my goals.
So here’s the math (since it interested me so much, I thought I’d share):
Start by calculating your weight in kg and height in cm. This is to calculate your BMI. There is also a handy tool online if conversions and multiplication is not your thing » Mine is 24.0 spot on!
They recommend a gradual weight loss of 1lb per week of fat. That equates to a 3500 calorie differential between what you eat and what you utilize (or burn) from activity. It averages to 500 calories per day, which may seem high but it’s really not. If you have weight to loose, you need to do this regardless – I got there slowly by eating more than my body needed each day so now to get back again, I just need do the reverse. It seems hard at the beginning because it’s a change and all change is hard until it becomes normal or routine, and then it’s okay (great pep-talk, yeah yeah).
You burn a certain amount of calories during planned activities. My trainer recommends at least 3 days of cardio/aerobic exercise and 3 days of strength training each week. That’s either 3 days a week if you double up or 6 days overall. Depending on your schedule, either works because it’s about how your body responds over the course of a week, not on a given day. You can calculate your calories burned from lots of websites; I obviously use the fitness tracker on SparkPeople. My ideal week looks like this:
- 3 x 45 min circuit of 4 super sets at 2 sets each, 15 reps per set: chest press/rows, squats/step ups, lunges with overhead press/triceps dip, back extensions/plank = 1210 calories
- 10 minutes of stretching upper & lower body after every exercise and/or cadrio workouts
- 5x walk to/from my car (1.5 mi circuit) = 540 calories
- 3 x 30 min walk, 3.5mph at 4:1 minute intervals using the incline (9:3%) = 360 calories
This is about 300 calories per day of exertion beyond my normal day to day stuff, when averaged over a week.
There is some more math to calculate your Base Metabolic Rate (BMR). This varies with age, weight and height. It accounts for your body’s ability to maintain a core temperature, keep your heart beating, lungs breathing, brain thinking, and food digesting. The math is complicated so I won’t get into it but SparkPeople does assume we all have a sedentary lifestyle (sitting at a desk, light housework, walking to the photocopier, watching tv, puttering on your computer, etc). They are unplanned, low exertion activities that equate to an equivalent weighting of 1.2 times your Base Metabolic Rate. My value is 1768 calories per day.
The final part comes with putting it all together: 1768+300 (activity) – 500 (1lb/week loss) = 1569 calories per day for eating. Assuming I keep up my fitness regime of cardio & weights, three times per week for each, I will meet my weight loss goal within 4 months, or less. I must remain committed to the circuit & cardio training, and eating within a range of 250 calories on the low side (which will accelerate my plan) or 100 calories over on some days: 1320-1670 range.
If you find comfort in the numbers, like I do, then I highly recommend you do the math. Here’s the page »
