I’m starting to take the wraps off my latest side project, http://tonight.im/, a site based on the notion that:

your check-ins + your weigh-ins = better choices

My office recently started a weight loss contest, and I bought this Withings Wi-Fi enabled scale to track my weight. The information from the scale is very helpful, but that data alone wasn’t helping me lose weight.

My biggest weakness when it comes to dieting is going out with friends, so tonight.im was created to turn that weakness into a strength. By telling me which check-ins (and ultimately which friends) are more healthy than others, it helps keep me on my toes and make healthier choices when I check-in to bars and restaurants.

WHAT THE SITE DOES

• It tracks your weight using a Withings Scale.
• It tracks where you eat, drink, go to the gym, and hangout using Foursquare
• It shows you the correlation between your weight change and your eating, drinking and gym habits.
• It uses your information along with others’ information to assign a “weight value” to bars, restaurants and gyms.
• If you want, it can send you a text message to remind of you of this information each time you check-in to a healthy or unhealthy place on Foursquare.

This last bit is key. It’s one thing to have a cool site where you can see where you’ve been, and what impact that has on your weight, but being healthy is all about consistently making the right decision in the moment. That healthy decision could be something small — maybe you order a hamburger instead of a bacon cheeseburger, or a glass of wine instead of a pint of beer. Heck, it might even be justification for an unhealthy decision like you’ve gone to the gym five days in a row, so you know what, you deserve the extra large milkshake. But at least you’re making a more informed decision.

This is an early proof of concept, so I’d love any feedback. Stay tuned for more.