Intermittent fasting: what it does and what it does not

Intermittent fasting is a schedule, not a mechanism. Its main effect for most people is straightforward: a shorter eating window tends to mean fewer eating occasions, which tends to mean fewer calories. That is a legitimate and useful thing for a tool to do — it is just not magic.

The common protocols

• 16:8 — a sixteen-hour fast and an eight-hour eating window. The most widely used, and the easiest to fit around a normal day.
• 14:10 — gentler, and often a better starting point if you train in the morning.
• 5:2 — normal eating five days a week, substantially reduced intake on two.

Where it genuinely helps

1. Structure. A rule you can follow beats a calorie target you negotiate with all evening.
2. Late-night eating. For people whose intake problem is after 9pm, closing the window solves it directly.
3. Fewer decisions. Skipping a meal removes a daily set of choices, which for some people is the entire benefit.

Where it does not

If you train hard and need substantial daily protein, compressing intake into eight hours can make hitting your target genuinely difficult. Fasting also does not pair well with high training volume for everyone — the session quality drop is real if you routinely train fasted and under-fuelled.

Who should not fast without medical supervision

• Anyone pregnant or breastfeeding.
• Anyone under 18.
• Anyone with a history of disordered eating — restriction-based rules can be actively harmful here.
• People with diabetes or on medication that must be taken with food.

This is general information, not medical advice. Speak to a qualified professional before changing how you eat if any of the above applies to you.

If you do fast, tracking it removes the guesswork about whether you are actually keeping the window. IGNYT runs a live countdown, shows the current stage, and keeps a history of completed fasts so adherence is a number rather than an impression.