How to Do a 5-Day Water Fast for Weight Loss (Safely and Simply)

Water fasting is one of the oldest ways humans have reset their health and dropped excess weight. A 5-day water fast can help you burn fat, reduce cravings, and give your body a genuine break from constant digestion — but it’s also a stress on your system. Done well, it can be both effective and safe. Done badly, it can leave you weak, dizzy, or running to the toilet for all the wrong reasons.

This guide will walk you through how to prepare, what to expect, and how to break a 5-day water fast without undoing your results.

Why a 5-Day Fast?

Five days is long enough for most people to:

• Enter deep ketosis (burning fat for fuel)

• Lower blood sugar and insulin levels

• Trigger autophagy (cell clean-up and repair)

• Experience noticeable weight loss

It’s also short enough that most healthy adults can do it at home — provided they prepare well and listen to their body.

Who Should Avoid It

Skip this fast unless you have medical supervision if you:

• Are pregnant or breastfeeding

• Have Type 1 diabetes or unstable Type 2

• Have heart, liver, or kidney disease

• Are underweight or recovering from an eating disorder

• Take medications that lower blood sugar or blood pressure

Step 1 — The Prep Phase (2–4 Days Before)

A water fast is easier if your body is already easing into fat-burning mode.

• Cut carbs: Drop bread, pasta, rice, sugar, and alcohol.

• Boost salt: ½ teaspoon of salt in water twice a day can help prevent low blood pressure headaches later.

• Stay hydrated: 2–3 litres of water daily.

• Ease off caffeine: Avoid withdrawal headaches during the fast.

Step 2 — The Fast Itself

What you can have:

• Plain water (tap, filtered, or mineral) — 2.5–3.5 litres/day

• Optional: electrolyte support — sodium, potassium, magnesium — especially after Day 2

• Unsweetened herbal tea if needed for variety

What to expect:

• Day 1–2: Hunger waves, possible headaches, drop in energy

• Day 3–4: Hunger usually fades, mental clarity often improves

• Day 5: You may feel lighter, calmer, and focused — or you may feel tired and ready to eat

Tips to get through it:

• Rest more than usual; avoid heavy workouts

• Distract yourself with light tasks, reading, or gentle walks

• If you feel faint, extremely weak, or have heart palpitations — break the fast

Step 3 — The Refeed (Critical!)

After 5 days without solid food, your gut needs a gentle restart. Jumping straight into pizza is a recipe for bloating, diarrhoea, and a quick return of water weight.

Day 1 (break-fast):

• Start with cucumber slices, bone broth, or soft zucchini

• Wait an hour or two, then have a small avocado or a few soft-boiled eggs

Day 2:

• Add more vegetables, berries, and a little fish or chicken

Day 3:

• Return to normal low-carb, whole-food eating

Expected Weight Loss

Most people lose 2–5 kg in a 5-day water fast.

• The first 1–2 kg is mostly water and glycogen.

• After Day 3, fat loss is the main driver.
  To keep it off, transition to intermittent fasting or a low-carb eating pattern.

Budget Tips for Seniors

You don’t need bottled “designer water” or expensive fasting kits. Tap water with a filter jug works fine. For electrolytes, you can mix your own with:

• Salt (Woolies/Coles pantry aisle)

• LoSalt (potassium chloride, Woolies)

• Magnesium citrate powder (pharmacy or online)

Bottom line:
A 5-day water fast is a powerful reset for weight loss and appetite control — but it’s not magic. Pair it with sensible eating afterwards, and you can lock in the results.