Fitness trackers and realistic weight loss

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11th Jun 2017 15:44 (UTC)

Fitness trackers are the latest offering in the dieting world. On their own their method is simple, do 10,000 steps a day and you'll lose weight. This goal is great if all you want is to have a less sedentary lifestyle. But how effective is it at actually losing weight?

Say you have 1 stone to lose for sake of ease, and your current weight is 189 pounds. Lets see roughly how many calories you will burn per step, how many in 10,000 and what that actually means in terms of weight loss.

First you multiply your weight in pounds by 0.57 to get the estimate for calories burned per mile walked:

Calories burned per mile walked = 0.57 x 189 = 107.73

On average there are 2145 steps per mile, based on your stride distance being about 75 centimeters (30 inches). So now we divide our figure by 2145 to get calories per step:

Calories burned per step = 107.73 / 2145 = 0.050223776

Now we multiply that by 10,000 to figure out how many calories your fitness tracker is trying to get us to burn:

Calories burned per 10,000 steps = 0.050223776 x 10000 = 502

If you burn off or reduce your intake by 500 calories per day, you will lose roughly 0.5 KG or 1 pound per week.

So what's the problem? Well aside from being half the speed you could be losing weight at safely, you won't actually be burning 500 calories per day. The average person walks about 2,000 to 3,000 steps per day anyway, the caloric cost of which is already dealt with by your Basal Metabolic Rate (BMR).

If we factor that into our 10,000 steps per day target we get:

Calories burned by typical daily walking = 0.050223776 x 2500 = 126
Excess calories burned at 10,000 steps = 502 - 126 = 376

At 376 excess calories burned per day, you will lose roughly 0.37 KG or 0.83 pounds per week. Which means it would take you 4 months or more just to lose that 1 stone at best, and that's with some generous averaging.

Furthermore, maintaining that excess burn doesn't just rely on you meeting your target steps every day. It also relies on your intake remaining the same and consistent. But the most likely scenario is that as you increase your physical activity, you will start feeling hungry. Potentially without even realising it within a few weeks you will be eating more than you did before and undoing the few excess calories you are burning by walking 3 extra miles everyday.

The only way to stop that from happening is to track your intake with a dieting app. But if you're needing to do that anyway, why would you not let the dieting app worry about your weight loss? You'll certainly get faster results.

Our web app lets you choose how fast you want to lose weight. On its medium setting it will give you 0.75 KG or 1.5 pounds of weight loss per week which is nearly double what a fitness tracker provides. On its fastest setting it will give you 1 KG or 2 pounds of weight loss per week, nearly triple.

In conclusion personal fitness tracking devices are great for helping you lead a less sedentary lifestyle. But as a weight loss product they're too slow and to see consistent results you have to put in more effort towards managing your intake anyway than you probably bargained for.