Breathalyzers attached to smartphones might help some lose weight

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    People who are dieting and exercising as part of a weight-loss regimen might have a new way to measure how much their work is paying off. Current tools such as scales and body mass index (BMI) calculators can help, but they can’t really pinpoint how much actual fat is being lost. 


    A new device


    Researchers at NTT Docomo, Japan’s largest mobile-phone provider, have been working on developing a solution – a device that can attach to smartphones and provide some insight into how much fat the user is burning.


    The findings were published in the Journal of Breath Research, in which authors Tsuguyoshi Toyooka, Satoshi Hiyama and Yuki Yamada explained how the breathalyzer works.

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    The device is described as a “portable and easy-to-use breath acetone analyzer” that uses pressure and gas sensors to analyze the breath. The researchers said this is the first prototype of this kind of device, and that it will soon be ready for consumers to self-monitor their fat-burning progress on a daily basis.


    Previous studies have provided evidence that there are more than 200 compounds in human breath, some of which correlate to various diseases. Acetone, in particular, is a product of metabolic processes. When people are burning fat, acetone is produced in the blood and is then exhaled from the lungs. The relationship between acetone and fat-burn is direct – the more fat that is being burned, the more acetone is being produced.


    Here’s what the scientists did

    In the new study, the researchers tested the device on 17 adults whose BMIs were above the Japanese standard (which defines obesity as having a BMI greater than 25). The United States’ standard defines obesity as having a BMI greater than 30. Participants included 11 men and 6 women, ranging from 21 to 70 years old.


    The subjects were divided into three groups, based on their caloric intake and amount of exercise. Group A was comprised of six subjects, who had no controlled caloric intake or light exercise. Group B had another six subjects, who were given light exercise for 30 to 60 minutes per day. The remaining five subjects were in Group C, who had controlled caloric intake based on the individuals’ body weight, in addition to the same light exercise as Group B.


    Researchers measured the participants’ acetone levels in their breath, as well as their body fat percentage and body weight, on a daily basis for 14 consecutive days.  Each participant was trained prior to the experiment so that he/she could blow consistently into the prototype. Their measured results were then sent to an Android-based smartphone through either a wireless Bluetooth connection or a wired audio cable.



    What did they find?

    The results of the study concluded that acetone levels in breath are a good indicator for monitoring fat-burning. Group A’s participants demonstrated constant breath acetone levels throughout the experiment, and they showed no significant fat loss. Group B’s participants demonstrated an increase in breath acetone levels during light exercise, but they had minimal fat loss. Researchers hypothesized that the subjects’ exercise intensity was too weak for fat loss. Group C’s participants demonstrated significantly increased breath acetone levels, which was also correlated with significant fat loss.


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    The bottom line

    Evidence from the study showed that the participants who maintained a regimen of controlled diet paired with light exercise lost the most amount of fat; however, they said one participant in Group C (6% of all participants) reached a plateau around the middle of the experiment. Researchers said this plateau that many dieters and exercises experience can be avoided by changing the extent of controlled caloric intake and/or exercise intensity during the experiment to continue to lose fat.


    Researchers said the results of their new study “have proved that (their) prototype can be used as a practical breath acetone checker for diet-conscious people, within an acceptable range of measurement error.” They said their study also “proved that breath acetone could be a good indicator for monitoring fat-burning and (their) prototype is useful for self-monitoring.”


    Some caveats

    Researchers maintained as many constant variables in the experiment as possible, including measuring the subjects’ breath acetone levels at the same time every day. Breath was analyzed before breakfast so as to not be immediately affected by food or exercise (an effect which previous studies have proven). However, levels of acetone in human breath tend to be relatively high in the morning before any food is consumed, researchers said.


    It should also be noted that different factors, including age, gender, BMI and metabolic disorders may have affected levels of breath acetone. In order to reach a more definite conclusion and account for the effect of individual factors, a larger-scale study would have to be conducted. Researchers of this study said they intend to do so.


    More about acetone

    Researchers said their breathalyzer device could not only play a role in daily diet and exercise management, but it could possibly help prevent and alleviate obesity and diabetes as well.




    "Assessing Your Weight: About Body Mass Index." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 13 Sept. 2011. Web. 12 Aug. 2013. <>.


    "Japanese BMI Calculator." Japanese Body Mass Index Calculator. N.p., n.d. Web. 12 Aug. 2013. <>.


    Toyooka, Tsuguyoshi, Satoshi Hiyama, and Yuki Yamada. "A Prototype Portable Breath Acetone

    Analyzer for Monitoring Fat Loss." Journal of Breath Research 7.3 (2013): n. pag. Print.

Published On: August 13, 2013