About FatFlow
Most people know what they ate. Far fewer understand what may be happening in the hours afterward.
FatFlow is a free educational app that makes the estimated shift between food processing, changing fuel sources and fat burning easier to see.
It is designed for awareness, not judgment. No calorie counting or prescribed diet. Your personal logs stay on your device.
100% free. No ads. No subscriptions.
The Story Behind It
FatFlow began after I learned that I had insulin resistance, prediabetes and fatty liver.
Understanding the role of meal timing and insulin changed how I looked at eating and helped me make changes that improved my health.
I built FatFlow to make this normally invisible process easier to understand, then shared it freely in the hope that it can help others.
How FatFlow Works
Log a meal, drink or activity. FatFlow estimates whether your body is likely:
It also shows the estimated time to the next state, your accumulated fat-burning time and patterns across different days.
These are educational estimates, not biological measurements.
The Science Behind It
After eating, insulin rises to help the body use and store incoming energy. Insulin also reduces the release of stored fat.
As time passes without additional calories, insulin generally falls and the body becomes more able to access and use stored energy. Activity can also influence how the body uses fuel.
This process is gradual. The body does not suddenly switch one fuel source off and another on. FatFlow uses three simple states to make the transition easier to understand.
In FatFlow, "fat burning" means an estimated period of greater reliance on stored energy. It does not mean that the body is using fat exclusively.
FatFlow does not measure insulin, blood glucose, metabolism or fat burning directly. Actual responses vary based on meal size and composition, activity, metabolism, sleep, medications and health conditions.
Sources
- National Institute of Diabetes and Digestive and Kidney Diseases — What Is Diabetes?
- Harvard T.H. Chan School of Public Health — Carbohydrates and Blood Sugar
- Santoro, McGraw and Kahn, Cell Metabolism (2021) — Insulin Action in Adipocytes, Adipose Remodeling, and Systemic Effects