I’ve had a nearly life-long battle with weight control. At one point in my early 20s I lost 80 pounds, reducing my body mass index,(BMI) from 35 to 22.8. Although BMI is far from a perfect indicator, over 25 is generally considered overweight while above 30 is considered obese. My weight has gone up and down since that, though never anywhere near as high as it was at that time.
Before I go on, I want to emphasize that I’m writing about my own journey and not giving any medical or health advice nor suggesting that everyone needs to keep track of their calories or body weight. I have consulted my doctor about my current weight-loss program and suggest you consider doing likewise. Also, BMI recommendations are general guidelines that don’t apply to everyone. On it’s web page about BMI, the Centers for Disease Control states “In general, a person who has a high BMI is likely to have body fatness and would be considered to be overweight or obese, but this may not apply to athletes. A trained healthcare provider should perform appropriate health assessments to evaluate an individual’s health status and risks.”
I did pretty well during most of the pandemic and — for a few months — stopped weighing myself on a regular basis. But when I stepped on the scale on May 12th, my weight was 165, with a BMI of 26.1, that put me in the overweight category. The reason I know the exact date and weight is because I use a $30 Eufy C1 smart scale that connects to my phone via Bluetooth to keep track of my weight and BMI along with other measurements. Although I’m just short of my goal, my BMI is now below 24.
The math behind weight control
Although there are all sorts of theories about what foods to eat when trying to lose, gain or maintain weight, the USDA, along with most other expert sources, agree that “You need to burn 3,500 calories more than you take in to lose one pound of weight.” In other words, you need a deficit of about 500 calories a day to lose a pound a week or 1,000 calories daily to lose 2 pounds in a week.
The math is simple but knowing how many calories you’ve consumed or burned is a lot more complicated. Many people under estimate what they’re consuming and over estimate the impact of exercise, but that’s where the Fitbit and other smart watches along with smartphones can help.
I don’t know of a technology smart enough to automatically measure everything you put into your mouth, but Fitbit, the Apple Watch and other smart watches are able to estimate how many calories you’ve burned. That’s because they can track your movement along with your pulse, and if they’re set up properly, they know your weight, height and gender, which all play a roll in determining how many calories you burn when sitting still or sleeping (basal metabolism) and when you’re exercising. The calculations aren’t perfect, but they’re pretty reasonable. As I sit writing this column at 8:30 in the morning, my watch tells me I’ve burned 545 calories so far today, which is very close to what Calorie.net’s BMR calculator says I should burn during 8.5 hours of little or no exercise. After I finish the column I plan to go for a brisk walk, which based on Fitbit’s previous calculations, should burn between 300 and 400 calories, depending on how vigorous my walk is. Walking faster or walking up hill will increase my heart rate and burn more calories. The watch will know all this by estimating my footsteps, tracking my distance via its GPS and keeping track of my pulse rate.
Later, I may spend 45 minutes on my indoor elliptical. There’s no distance travelled for the GPS to measure, but if I remember to tell the watch what exercise I’m doing it will estimate calories based on time and heart rate.
Even if you don’t have a smart watch, you can get similar information from your Apple or Android phone. The Apple Health app and the Android Fit app do a pretty good job of tracking calories burned when walking, running or cycling.
Again, none of these measurements are perfect, but they’re probably better than anything you would come up with based on your own observation and — over time — they’re close enough.
Calories consumed
The Fitbit app has a way to enter everything you eat, and it has a database with calories and other nutritional data on just about every type of food I’ve entered into it. The trick is remembering to enter everything and entering the correct quantity. If I want to be as accurate as possible, I would weigh or measure every ingredient before I enter it in, but that’s not usually practical. Sometimes I’ll override the app’s calorie estimate based on the food’s nutrition label. Again, it’s an estimate and not an exact science.
It gets tricky when you go out to eat and don’t know what ingredients are in your food. The Fitbit app has nutrition data for most major restaurant and fast food chains, but I tend to eat at lesser known local establishments, so I estimate how much I’ve eaten during the meal.
Other factors
I have my Fitbit set to lose a pound a week and — most days — have had that 500 calorie deficit required to lose at that rate but even if I stay within my goal on a given day, my weight might be higher or lower than I expect when I step on the scale the next morning. If I gain a pound, it’s not because I ate an extra 3,500 calories the day before but most likely do to water retention which may have more to do with sodium than calories. For example, last night I went out for Chinese food and wound up gaining nearly two pounds compared to the day before. I’m 100% certain I didn’t consume an extra 7,000 calories, but even if I did consume more than I burned that day, that weight gain was definitely not excess body fat and will go away within a couple of days if I reduce my sodium level. And, despite the numbers, I’ve lost less than a pound a week, which is OK because the trend is in the right direction.
Final thoughts
I realize that this article might make me seem obsessive, and there are many people who might be better off not being so precise when it comes to tracking their food and exercise. But I’ve actually found that keeping track is pretty easy and pretty effective in keeping me on track. And, as I age, the stakes are higher when it comes to health. My father died at 61, likely of complications related to his obesity.
It’s taken me a lot longer to lose the desired weight than it would have when I was younger, but keeping track of calories consumed and burned does help me stick to my goal. Having said this, I’m cognizant of the fact that most people who lose weight put it back on, and I’m humbly aware of my own past setbacks when it comes to weight control.
Larry Magid is a tech journalist and internet safety activist.