Intermittent fasting is a schedule, not a diet. It changes when you eat rather than what you eat.
This guide covers the common protocols, what you can have during a fasting window, how training fits around it, and who should not fast at all.
Key points
- Fasting protocols change the timing of meals, not their content.
- 16:8 and 5:2 are the two patterns you will come across most often.
- Water, black coffee and plain tea are generally taken during a fasting window.
- It suits people who prefer fewer, larger meals and dislike constant planning.
- It is not suitable for everyone, and there are groups who should not fast.
What is intermittent fasting?
Intermittent fasting means alternating between periods of eating and periods of not eating, on a set schedule.
It says nothing about what you eat. Two people can follow the same protocol and eat completely differently, which is why it is better thought of as a structure than as a diet.
What are the common protocols?
A handful of patterns account for most of what people actually follow.
- 16:8. healthdirect describes this as eating for an eight hour window in a day and fasting for the remaining sixteen.
- 5:2. Eating normally on five days a week and sharply restricting intake on the other two.
- Alternate day. Alternating between normal and heavily restricted days.
- One meal a day. Often shortened to OMAD. The most restrictive of the common patterns.
Which one do people stick with?
16:8 tends to be the most durable, largely because for many people it amounts to skipping breakfast and finishing dinner a little earlier. That is a small change to a normal week.
What can I have during a fasting window?
Water is the straightforward answer. Black coffee and plain tea are also commonly taken.
Anything with energy in it ends the fast, which includes milk in coffee, juice and soft drink. Whether a splash of milk matters in practice is a question of how strictly you are following the protocol.
Staying properly hydrated matters more than people expect, particularly if you are also eating low-carb.
Who should not do intermittent fasting?
This is the part that gets least attention online and matters most. healthdirect states plainly that intermittent fasting can be safe for some people but is not suitable for everyone, and that it is important to talk to your doctor before you start.
Important. healthdirect advises that you should not do intermittent fasting if you are underweight, have or have previously had an eating disorder, are pregnant or breastfeeding, are a child or teenager, are an older adult, or take daily medicine that must be taken with food. If you are having treatment for cancer or taking diabetes medicines, talk to your doctor about whether it is safe for you.
If a fasting schedule leaves you preoccupied with food or bingeing when the window opens, that is a signal to stop and speak to a professional rather than to push harder.
Can I train while fasting?
Many people do, though it takes some adjustment and it does not suit every kind of session.
Lower-intensity work is generally more comfortable fasted than heavy or repeated hard efforts. Some people find they simply train better with food in them, and that is a reasonable thing to design around rather than override.
A practical arrangement
Scheduling your eating window so it covers your session is the simplest fix, and it is what most people who lift end up doing.
Does fasting work better than other approaches?
Not inherently. It is a way of organising your eating, and its main advantage is practical: fewer decisions and fewer meals to plan.
If you like structure and dislike constant food admin, it can be easy to maintain. If long gaps without food make you irritable or lead to overeating later, another approach will serve you better.
The one you can keep doing is the one worth choosing.
Sources
Sources are cited for the general health information in this article. They do not endorse any product or brand.
- Intermittent fasting, healthdirect Australia
