Fat loss & accountability

How Much Weight Can You Realistically Lose in 28 Days?

By Maciej Nowicki · Updated 2 September 2026

Most people can realistically lose 4–8lb (2–4kg) of actual fat in 28 days, plus 2–5lb of early water weight on top. Heavier starting points lose faster — 10–14lb is possible from 18 stone plus. The number that matters more is how much stays off, and that depends on how you lose it.

I'm Mac, and I literally run a 28-day programme — the Lock In & Lean Out Blueprint — so I've watched this exact window play out over and over with real people. Which means I can give you something the health sites can't: not just the textbook maths, but what the scale actually does across four coached weeks, and the answer to the question everyone's really asking — how much of it stays off.

The honest numbers, by starting point

Fat loss runs on a calorie deficit: roughly 500 calories under your TDEE per day is about 1lb of fat a week. But the honest ranges depend heavily on where you start — bigger bodies burn more and can sustain bigger deficits:

Tommy started at 133kg and averaged around a kilo a week for ten straight months — so his first 28 days were near the top of that table. Someone chasing their last half-stone will never see those numbers, and shouldn't try to.

Why week one lies to you (pleasantly)

Start eating in a deficit and the scale drops fast — often 4–6lb in week one. Most of that is glycogen and the water stored with it, not fat. It's real weight and it's allowed to feel good, but don't multiply week one by four and book a photo shoot. Weeks two to four are the truth: steady, smaller drops that are mostly actual fat. I tell every Blueprint client this on day one, because the person who expects week one forever is the person who quits in week three.

How much of it actually stays off?

This is the question the forums ask and the diet industry avoids, so here's the straight version. What you keep depends entirely on how you lost it:

• The water weight comes back the day you eat normally again — it always does, it's glycogen, and it isn't failure.
• Fat lost through a sensible deficit stays off exactly as long as the habits that created it stay on. The fat has no memory; your routine does.
• Crash losses rebound almost by design: starve off 12lb in 28 days, and you've practised nothing you can repeat in month two.

This is why my 28 days is built as a bridge, not a blowout — your food set properly, your training built into your real week, and a coach checking you actually did it. Craig's the proof of what that start can turn into: he won a place on the challenge as a giveaway, back when he couldn't run 2k without being sick. He never stopped — about a year later he crossed the Leeds Marathon line in 4:27:43. His story's on the results page.

Can you lose 2 stone in a month?

Almost certainly not as fat, and you shouldn't want to. Two stone (28lb) in 28 days means a deficit north of 3,000 calories a day — starvation territory, where you lose muscle, energy, and every habit you were supposed to be building. The exceptions you see online are very heavy people in week one (water), or people about to rebound. Chase the table above instead; it compounds.

What 28 days is actually for

Four weeks won't finish the job — but it's exactly long enough to prove to yourself that the job is doable. You come out with a visible drop, your food finally making sense, two or three training days that survived real life, and — the bit that actually predicts year two — evidence that you're someone who does what they said they'd do. That's the point of the Blueprint (£197, once): 28 days, coached, no tie-in — and if you want to keep going afterwards, you already know how the coaching works.

FAQs: losing weight in 28 days