Nearly half of adults in the UK who self-track with mobile devices say they've experienced "strong behavior change", according to a survey by the Trajectory Group, sponsored by Fitbit.

The data comes from the Fitbit Healthy Futures Report, a study on the role mobile devices play in health and wellness in the United Kingdom commissioned by Fitbit UK. Trajectory surveyed 1,005 people between the ages of 18 and 54 in April 2013, and spoke with a number of experts.

Twenty-five percent of adults aged 25 to 34 said they "run their lives through their smartphone" and 25 percent of adults aged 25 to 44 said motivational prompts through their smartphone would have a huge effect on their health choices.

The study looked at self-tracking and the results were similar to recent Pew data on that topic, namely that most self-trackers track in their heads. Fitbit found that seven in 10 British adults tracked their health -- exactly the same figure as Pew found for Americans.

The study found that 68 percent of self-avowed health trackers tracked just in their heads, 31 percent used a computer program, website, or mobile device, 23 percent used paper, and 7 percent used a medical device. When asked about how effective their tracking was on health changes, the medical device group was most likely to say it was effective (70 percent) followed by the technology and paper groups (47 and 45 percent). Only 24 percent of head trackers found that tracking to be effective.

The authors argue that their data shows self-tracking to be potentially much better for behavior change than other strategies. They found that many respondents saw public health campaigns from groups or celebrity endorsers as "lecturing" and responded poorly to it. In fact, 63 percent of respondents agreed with the statement "I like to do my own thing. I don't like being lectured and told what I should be doing." Only 10 percent said that kind of messaging had any positive effect on their lifestyle.

Finally, the study asked people which was most important: looking good, feeling good, or performing well in their every day lives. Feeling good was the top pick, at 46 percent, followed by looking good at 23 percent and performing well at 19 percent.