Posted on April 11 2018
If you're reading this, there's a good chance that you or someone close to you wears a fitness tracker/smart watch. It definitely seems like a cool tool for helping you accomplish your fitness or weight-loss goals.
If you know exactly how many calories per day you are burning, then all you have to do is eat less calories than that and you should lose weight. Want to lose even more weight? Simply increase the deficit in calories between what you are eating and what the fitness tracker says you are burning. It’s fool proof right?
Maybe not. See, this little system is dependent upon your fitness tracker working properly, that is, measuring calories burned accurately. If the tracker says you burned 2,500 calories today, but it's off by 20 percent, then what you thought was a nice fat burning deficit in calories may end up being no deficit at all. Even worse, it could end up being a surplus in calories eaten!
In order to eat the right number of calories to support your goal, you need to make sure your tracker is accurate. How can you do that? Luckily, you don't have to! The brilliant minds at Stanford School of Medicine have done exactly that (hint, none of them are accurate!).
The Stanford Researchers evaluated 7 of the top devices: The Apple Watch, Basis Peak, Fitbit Surge, Microsoft Band, Mio Alpha 2, PulseOn and Samsung Gear S2.
Here is what they found:
The devices were terrible at tracking calories burned (energy expenditure): The Apple Watch was reported to be the most accurate, while the Samsung is the least accurate. But even the most accurate device was off by an average of 27 percent! That equates to a 500 calorie or more variance making the measurements all but useless.
The devices were surprisingly accurate at measuring heart rate. Heart rate data can be important depending on the type of training that you are doing, but is of minimal value in the context of planning your diet.
The device readings were less accurate in men, especially those with a higher body mass index, the very people who need accurate readings the most.
That’s not good! If wearables are not accurate at estimating how many calories you burn, how do you know how many calories per day you should be eating? Luckily, there is an easy way to figure that out.
You will need to calculate your basal metabolic rate (BMR), which is the approximate number of calories that your body burns per day at rest.
This involves some basic math, but for the sake of making things as easy as possible, you can click here, which will take you to a calculator that will do the math for you!
Once you have your BMR, you will need to use the Harris Benedict equation to approximate the number of calories that it takes to support your activity level per day.
The Harris Benedict equation is very simple.
You will simply take your BMR and multiply it by the appropriate activity factor below:
- If you are sedentary or get little to no exercise, you will multiply by a factor of 1.2
- If you are lightly active (light exercise 1-3 days per week), use a factor of 1.375
- If you are moderately active (moderate exercise 3-5 days per week), use a factor of 1.55
- If you are very active (hard exercise or very physical job 6-7 days per week), use 1.725
- If you are extra active (competitive athlete/2-a-day training), use 1.9
The final number is the approximate number of calories that you will need to eat per day to maintain your current weight.
Once you have your total daily caloric needs figured out, you just need to identify your goal, whether it's weight loss or lean mass gain, and then create either a caloric surplus or caloric deficit.
Keep in mind that the goal is to lose body fat or gain lean mass, not simply lose or gain weight. Said another way, you can only lose body fat or gain muscle so quickly. If you are losing weight too quickly, chances are you are losing lean mass along with your body fat, which is not what you want.
The same is true for gaining lean mass. If the scale is going up too quickly, you're probably gaining more body fat than you would like to go with your lean mass.
If you naturally have a fast metabolism, then you will need to consume more calories than someone with a slow metabolism in order to gain mass.
Similarly, if you have a slow metabolism, you'll likely need a larger deficit in calories in order to lose weight, compared to someone with a fast metabolism.
I suggest starting with a 500 calorie daily deficit for weight loss if you have a hard time losing weight, and a 350 calorie per day deficit if you have an easier time losing weight.
Conversely, if you want to gain lean mass you can start with a 500 calorie surplus if you have a hard tome gaining mass, and a 300 calorie surplus if you have an easier time gaining weight.
Stick to these number for 2 weeks and then assess your results.
If you aren’t satisfied with your results, you can then increase or decrease you calories. I would suggest doing so in 200 calorie increments. Once you change the caloric load by 200, wait another 2 weeks and then assess your results again.
Remember, weight loss or gain is a marathon not a race. You are looking for steady results over time, not drastic results that are unsustainable in a short period.
The major determining factor in whether you gain or lose weight is your caloric intake, so work on getting that right first.
Once you are eating the right number of calories, you can work on making sure your macronutrients, often called macros, are optimal for your goal.
In simpler terms, this refers to making sure you are dividing your daily calories into the right ratio of protein, carbohydrates, and fats.
We will cover macros in a future blog post, so get your calories in order and we will take macros soon!
If you have questions about anything that we covered, please tell me what they are in a comment below so we can get them answered.