Fat-Burning Mode

Welcome Fat Burning to Zero 

Based on your input, we’ve made it even easier to track your time in Fat Burning and to understand which activities help your body transition to primarily burning fat for fuel.

This updated feature is in active development and rolling out on iOS first and your experience may vary slightly. 

• What is a fasting zone?
• Introducing Fat Burning
• How We Calculate Your Fat Burning
• Burning Fat, Faster
• FAQs 

What is a fasting zone?

Fasting zones are a way to understand what's happening inside your body during a fast. Zero Plus members can track their time in Fat Burning, with real-time insights into how their diet, weight, and activity impact time in this zone.

Until now, fasting zones were standardized timeframes that showed the current fasting state of your body. These standardized timeframes were:

• Anabolic: 0-4h of a fast (4 hours in length)
• Catabolic: 4-16h of a fast (12 hours in length)
• Fat Burning: 16-24h of a fast (8 hours in length)
• Ketosis: 24+ of a fast (48 hours in length)

While your body is always burning fat, around hour 16 of your fast it shifts to using fat primarily for fuel. This shift persists even into Ketosis and Deep Ketosis.

Fat Burning Mode

Our proprietary model is built on the science of your metabolism. Using the information you provide, we give you real-time insight into how you are progressing through your fast by tracking hours spent in Fat Burning.

We represent the time that your body is primarily burning fat for fuel (Fat Burning) as progress on your Timer ring. Each flame represents an hour of peak Fat Burning. We recommend a daily fasting practice of 13-18 hours, helping you to balance Fat Burning with ample time to enjoy healthy meals during your eating hours.

To understand your current Fat Burning progress, tap the button just below the timer, with three flames between your fast start and stop time. This will open a view letting you know whether you are yet to reach peak Fat Burning, or have spent 0-1h, 1-2h, or greater than 2h with fat as your primary fuel source.

  

How We Calculate Your Fat Burning

When you start your first fast with Zero we ask for your typical daily activity level, habitual diet, age, weight, and height. We use this information to calculate your personalized time to Fat Burning during each fast.

Logging a lower weight, or a healthier than average pre-fast meal, will change your time to Fat Burning. Our model even continues to adapt as you age.

Burning Fat, Faster

These data points give us your standard time to Fat Burning, but there are ways to shift your body’s metabolism even sooner. Logging activity, while your fast is in progress before you reach Fat Burning, will play a celebratory animation indicating that your time to Fat Burning has changed.

For more information on connecting your health data to Zero, read our Connected Apps pages:

• Apple Health & Google Fit
• Fitbit, Oura, & Biosense

FAQs

• Q: How long should I fast to reach Fat Burning?
• A: Many Zero members can reach Fat Burning within a 16-hour fast, particularly if they log activity during their fast.
  
  
• Q: How can I see how long I've been in Fat Burning Mode?
• A: Tapping the center of the timer ring during a fast will cycle through the following views:
  • Total elapsed fasting time
  • Total remaining time left for fast goal
  • Elapsed time in fat burning mode
• Q: When should I exercise to reach Fat Burning?
• A: We recommend a short walk after you start your fast to boost digestion. You can also enjoy some moderate-intensity activity in the morning after you wake up. We do not recommend strenuous activity before sleep as this can compromise the quality of your sleep.
  
  
• Q: You mentioned other fasting zones, how can I track these?
• A: At Zero we believe in simplifying the science of fasting and have chosen time to Fat Burning Mode as our core metric for fasting zones. While you will still experience the benefits of Ketosis and Deep Ketosis (such as autophagy) during your fast, this will typically occur after 24 hours.