How I Use My FitBit, Diet and Exercise To Lose Weight

What the doctors and diet industry won’t tell you is that if you want to lose weight, you need to make eating and exercising work together. Why? Suppose your BMR is 2,200 and you don’t exercise beyond about a mile’s walk on the commute and to get lunch. That’s about 2,300 calories (that’s right, one mile at 4 mph at a reasonable weight is 100 calories. See why exercise alone won’t do it?) At a 500 calorie daily deficit, that’s 1,800 calories. Do that to your body a couple of times and homeostatis is going to kick in: your body is going to turn down the energy it uses to get through the day to allow for the lowered intake. This is where the exercise takes effect: not only does it force your body to burn calories, but it tells it that there’s an expectation of higher activity rates and it had better stay alert. This counters the homeostasis, and you get your 500 calorie deficit.

Okay? Eat less, body slows down; exercise more, body speeds back up again. That’s why we need to do diet and exercise together.

My Fitbit tells me the number of calories I have left to eat today, assuming I don’t do any more over-the-BMR activity. This is often a scarily low figure. I used to have very inactive Saturdays, and had used up my allowance after breakfast and lunch. If the calories left falls below about 200, I know it’s time to get some walking or exercise in (because hot chocolate drink in the evening). Basically, I keep going until the "calories remaining" is back where I need it. Now, I don’t actually just walk round our office (not trivial, you could run the 400 metres round the full length of my floor) until I use up 250 calories, but it does encourage me to, say, get off at Oxford Circus and walk rather than go to Piccadilly Circus, which is just round the corner from my gym. That’s often all it takes.

It’s not enough to say “If you eat a little too much, you can walk it off.” You need to know you’ve walked it off.

It’s not quite as closely-managed as I may have made it sound, but it’s possible because the Fitbit, or any other tracker with the same functionality, makes it easier to monitor my activity and intake. As with checking the calories / 100 grammes on food packaging, it’s a habit that’s easy to get into and quickly becomes automatic. Using this method, I’ve kept up a 500+ calorie / day deficit for three weeks, with no real pain.