Actor Jon Hamm, former President Barack Obama, and Google CEO Sundar Pichai have all been spotted wearing fitness trackers and smartwatches — the latest tools designed to count your steps, heart rate, and calories burned, as well as monitoring your sleep quality.

They can cost anywhere from $13 to more than $400. Or you can download a free pedometer to your smartphone. Research shows the devices promote adherence to exercise goals and help boost weight loss efforts.

So which type is your best choice?

A study in the British Journal of Sports Medicine found that for overweight/obese people who have weight-related health conditions, all the wearable fitness trackers and step counters promote weight loss. However, simple step counters and calorie counters were associated with the most weight loss and the greatest reduction in body mass index (BMI).

And when a step counter was combined with dietary changes or coaching, people’s BMI went down by 3.4 — for instance, from 28, which is overweight, to 24.6, which is in the normal range.

The benefit comes from easy goal-setting (10,000 steps a day), clear readouts, and straightforward notifications about when it's time to move, when goals are met, and how many calories have been expended.

Other helpful measures to boost weight loss plan include these top five tips from the Cleveland Clinic:

• Don't skip breakfast and get at least 10 grams of protein.

• Eat small meals or consider intermittent fasting.

• Exercise moderately and make sure to add in resistance/strength training.

• Eat until you're no longer hungry, not until you are full.

• Beware of emotional eating.