My interest in intermittent fasting (IF) started several years ago when I learned that Hugh Jackman used a daily 16-hour fast to lean up for his role in Wolverine.

I knew this was a fun body hack to lose weight, but that doesn’t mean it’s healthy for you. To assess the health benefits (both positive and negative), we need to turn to the only data we can truly trust: research published by scientists in peer-reviewed journals.

When you dig through the data, it starts to get pretty exciting. It decreases breast cancer risk and recurrence by as much as 36%, improves sleep, has positive effects on markers of systemic inflammation, and regulates blood glucose levels and other aging biomarkers. Furthermore, Dr. Longo’s clinical trials have demonstrated efficacy for type 2 diabetes, multiple sclerosis, and cancer patients.

All the benefits mentioned above (and more) are covered in a wonderful video series by Dr. Rhonda Patrick, where she interviews scientists Dr. Valter Longo, Dr. Satchin Panda, and Dr. Ruth Patterson. I highly recommend that you watch all three of these videos if you’re new to fasting.

We created Zero (named for the amount of food you eat while fasting) as a simple way to track your daily fasting.

Zero comes with two predefined fasts but is also completely customizable, allowing you to define your daily fasting hours and days per week.

Right now (with my doctor’s approval), I’m doing a custom circadian rhythm fast, based on Dr. Panda’s research. This type of fast has two goals: 16 hours of fasting, and eating as close to sunset as possible. Dr. Panda’s research shows eating late into the night can be detrimental to your health.

Zero tracks hours fasting as well as your nighttime eating by fetching your phones location and calculating local sunset time. For example, if the sun set at 6pm, and you began fasting at 8pm, Zero would automatically log two hours of nighttime eating. All of this data is stored on your device and is available for you to export at any time for further analysis. I export the data monthly to look at larger trends and to ensure I’m keeping my nighttime eating to a minimum.

Zero is available for download now (iOS) and is forever free. I hope you enjoy it.

Reminder: Before fasting, it’s important to talk to your doctor. As Dr. Longo says, “Whether you’re thinking about trying a fasting system for preventive reasons or as a treatment, the doctor should be involved… There are many factors that must be considered, like your current diet, or whether you have diabetes or a metabolic disorder.”

Many thanks to Caleb Davenport, Daniel Burka, and Tara Mann, who donated their time to help make this a reality.