DefinitionIntermittent fasting is an eating pattern that cycles between set eating windows and fasting periods, such as eating within 8 hours a day.
What it means
Common styles include:
- 16:8: fast 16 hours, eat within 8
- 14:10: a gentler starting point
- 5:2: eat normally 5 days, sharply cut calories 2 days
Studies generally find intermittent fasting works about as well as everyday calorie cutting. It helps mainly because a shorter window makes it easier to eat less.
On a GLP-1, appetite is already low, so a tight window can make it hard to reach protein and fluid goals. People with diabetes, especially on insulin or sulfonylureas, should ask their care team first because of low blood sugar risk.
If you try it, start with a wider window like 12 or 14 hours and see how your energy, sleep and protein intake hold up before narrowing it.
Why it matters
The fasting calculator builds a window around your schedule while flagging the protein you still need.