Last October Waterloo, Ontario-based Airo Health, a small startup founded by recent graduates, began taking preorders for a passive nutrition-tracking, wristworn device on its website, only to refund its backers a few weeks later after admitting it should have tested and validated the device further before putting it up for sale. Last week Healbe, a company with offices in San Francisco and Russia, began a crowdfunding campaign on Indiegogo for a similar device, called Gobe, that claims to passively track caloric intake, hydration levels, stress, activity, sleep phases, and more. In just one week that company has already raised almost $350,000 -- more than tripling its $100,000 goal.

Last year we noted that many of our readers expressed disbelief that Airo’s prototype device could accurately use a wristworn optical sensor to detect caloric intake -- I have received similar notes from readers about Healbe.

Here's Healbe's description of GoBe from its crowdfunding campaign: "GoBe doesn't require you to keep a food diary, scan bar codes, or take photos of your meals. It automatically calculates calories consumed by measuring the amount of glucose in your cells, through your skin. Only GoBe uses Healbe FLOW Technology to combine a unique algorithm with measurements from the body manager's pressure, accelerometer, and impedance sensors to show you calories consumed; metabolic rate and calories burned during any activity; hydration; sleep; and stress."

In an email to MobiHealthNews, Healbe CEO Artem Shipitsin wrote that, "Yes," the "device actually works" but that Healbe doesn't have validation "right now [from an] independent company". All of Healbe's validation testing so far has been done in-house as part of the device's development. Shipitsin said that the company has tested GoBe's glucose sensing against a traditional glucose meter's readings and the GoBe's level of accuracy usually falls within the 80 percent to 85 percent range. Healbe also compared its device's detection of caloric intake up against what standard caloric tables say the meal being tested contains, and Shipitsin said GoBe was usually within 88 percent to 92 percent accurate. He also promised to make documents from an independent testing facility available to MobiHealthNews once they go through such testing.

When it first began taking preorders last year, Airo also told MobiHealthNews that it had validated its device in-house and that it planned to have it independently validated in the future.

Healbe expects to ship its devices to those who preorder via Indiegogo in just a few months -- June 2014.

While whether Healbe's GoBe device works as advertised remains to be seen, its concept might shed some light on the rumors circulating about Apple's iWatch and the reason the iPhone maker has been snapping up noninvasive glucose sensing experts for the past few years. As we have argued in the past, it is unlikely that Apple would add functionalities to its iWatch and make medical claims about them that would put the device in the FDA's crosshairs.

Maybe all those noninvasive glucose sensor experts joining Apple are working to build a GoBe-like device that can passively detect caloric intake. Maybe Healbe built it first. Or, like those who preordered the Airo device found out, and -- perhaps Apple's team is finding out behind closed doors -- the feasibility of passively detecting caloric intake via a wristworn wearable device just isn't here yet.