If your goal is weight loss, you still need to be at an overall caloric deficit.
Rule of thumb: Do longer fasts (more than 24 hours) less often; do shorter fasts (less than 24 hours) more often.
If your plan is to start with 16:8, you can do that every day. In fact, doing it every day will help you get used to it quicker. 16:8 is pretty much just “skip breakfast and cut out late-night snacking” — it isn’t super strenuous on the body, and that means it’s generally fine to do every day, even when first starting.
Yes, you can still exercise.
To gradually increase your fasting time, wait until you get used to 16:8 and it starts feeling easy/normal. Then increase by an hour or two.
But just note that you may not need or want to fast longer! Plenty of people get the results they want on 16:8. Longer fasts aren’t automatically better for weight loss or health. It’s all about finding the schedule that feels natural for you — your body and your lifestyle.
Bonus advice: Expect an adjustment period of a week or two. During this time, your body will send hunger signals at your old mealtimes. Be aware that these hunger signals are mostly just habit — they typically don’t actually mean your body needs fuel. They were just part of the process of your body preparing to digest food at the usual times.
The useful secret is that these kinds of hunger pangs don’t continuously keep getting worse: If you just wait them out, they will go away on their own in an hour or so. After a week or two, your body will adjust to the new meal schedule and stop sending hunger signals at the old mealtimes.
When you do feel hunger pangs during your fasting period, don’t panic. Instead, take a pause and check in with yourself physically and mentally. Notice and name your physical feelings, emotions, thoughts. This helps to learn the difference in how true hunger feels, vs. habitual “hunger”, or a desire to eat out of boredom or stress.
You’ll likely start to notice a difference in how you feel at, say, 12 hours of fasting, vs. 16 hours. This will help you learn your body’s true signals.
If you feel dizzy, faint, weak, highly nauseated, severe pain anywhere — those are danger signals and you should break your fast. However, those are quite rare to run into during IF, especially 16:8.
I’m not an expert, just my take. You MUST count calories, I use myFitnessPal. You need to eat less calories than you weigh x 10. ( ex if you weigh 300 pounds, then you need to eat like 2200 calories, to lose weight over time)Do IF everyday, and yes exercise still. Walking helps a lot!Finally, drink a ton of water each day, like 64 ounces at least. Just my thoughts, not medical advise!