Randal Constant has been tracking himself for a long time. Back in 2010 he started using a Nike device that tracked mileage with a sensor in his shoe. Three years later, he bought a Nike+ FuelBand.
"I worked that until the day it died," the 57-year-old said. "The day it died, that's when I ordered my Fitbit."
That was in July. He's lost 51 pounds since.
Activity trackers, made by companies like Fitbit and Garmin, are becoming must-have accessories. They can measure things like how far you walk, how intensely you exercise and your heart rate. Basic models counting your steps cost as little as $60, but more sophisticated trackers go for hundreds of dollars.
As they become more popular, stories like Constant's are increasingly common. But how much can an activity tracker really improve your health?
You need to be motivated
Patrick C. Shih, a professor of informatics at Indiana University Bloomington, has studied how people use technology to help themselves lose weight. He's found that for people who are motivated to lead healthier lives, activity trackers can push them to continue.
But, he said, "If you aren't already motivated, the tracker doesn't help you very much."
Personal motivation is key to meeting your health goals, Shih said. It also helps to have the support of your peers and, ideally, a role model who shares characteristics.
Constant's motivation is his 29-year-old son, Calvin, who has cerebral palsy and uses a wheelchair. Constant wants to stay in shape to keep taking care of Calvin.
"You've got to try to stay around as long as you can," the New Orleans resident said.
How he lost the weight
Constant is a data-oriented guy. He told me he "loves spreadsheets." The Fitbit comes with ways to visualize the data it collects, but Constant went further, charting it in Excel.
The August after he bought the Fitbit he started walking — a lot. He bought a Fitbit Aria scale (the newest model is listed for $130 on the company's website) and started tracking what he ate.
"The main thing is to find things you like and get a good idea of what the calories are and keep track of that," Constant said.
Constant aimed to eat foods that were high in protein and low in carbohydrates and used fatty foods as a reward. (Remember, everyone's dietary needs are different. Consult a physician or nutritionist for formal advice on how to lose weight.)
Tracking his activity, his calories burned, his calories consumed and his weight encouraged Constant to keep going.
"You knew you were making progress," he said.
Even though he kept his intake to 1,500 calories a day and walked about 12 miles a day, Constant said it was "really, really easy." He treated his diet like a business: The calories he burned were his income and the calories he ate were his expenses. If he kept income above expenses, business was good.
Constant has run and walked all his life. Burning calories was not a problem. But he's worked in the food business for 40 years. He looks at food or reads about food or thinks about food all day. It made it hard to control what he ate. Once he started keeping track, he felt more confident.
How an activity tracker can help you
Constant used his device to make progress toward his weight loss goals. People trying to lose weight can also use their activity data for comparison purposes, Shih, of Indiana University, said. Many trackers let you share your data in online communities where users can exchange tips on diet or exercise and offer encouragement. Having precise data can make it easier to find people who share your circumstances and offer better advice.
An activity tracker also provides sophisticated feedback on your workout, with some devices measuring how quickly you step while running, your VO2 max (a measure of how much oxygen you can use during intense exercise) and your heart rate. These trackers may help more serious athletes set more specific goals for themselves, but they're also more expensive, Shih said.
What to know before buying an activity tracker
Constant started tracking his food Sept. 7. In the 115 days that followed, he lost 51.2 pounds. His goal was to lose 30. His heart rate and blood pressure have also improved.
Constant is a Fitbit apostle now. He plans on having a wearable tracker for the rest of his life.
"It was worth it," he said. "Positively."
But not everyone will draw as much encouragement from the numbers an activity tracker provides. Remember: The device won't help you get healthy unless you're already motivated (though it may help you save on health insurance). Before buying an activity tracker, consider whether you'll actually have activity to track.
If you haven't used an activity tracker before, you may not want to buy the most feature-rich and expensive product out there. You don't want to waste money on something you only use for a few weeks and then abandon, Shih said.
"Be reasonable," Shih said. "Start with the entry level and work your way up."
Get essential money news & money moves with the Easy Money newsletter.
Free in your inbox each Friday.