One pound a week. It's the rate the NHS recommends. It's not flashy. Nobody's selling a TV programme called Lose A Pound. But it's also the rate that actually works long-term for most UK adults — and there's solid maths behind why.
The maths
1 lb of body fat ≈ 3,500 calories.
To lose 1 lb of fat in 7 days, you need a 500-calorie daily deficit:
500 kcal × 7 days = 3,500 kcal = 1 lb fat
That's the entire scientific basis. Everything else — keto, fasting, slimming clubs, GLP-1 medication — is just different ways of getting you to that 500/day deficit.
How to create your 500-calorie deficit
You can do this through food alone, exercise alone, or a combination. Most evidence shows combining is the most sustainable.
Option A: All from food
Cut 500 kcal from your daily eating. Examples:
- Skip a 600-kcal lunchtime sandwich, replace with a 200-kcal salad with chicken, gain back 100 kcal of biscuits in the afternoon — net cut: 300 kcal. Still need another 200.
- Cut your daily glass of wine (~150 kcal) and a packet of crisps (~150 kcal) and the milk in 4 cuppas (~100 kcal) and a biscuit (~100 kcal). Net cut: 500 kcal.
Option B: All from exercise
Burn 500 kcal/day through exercise. For an average UK adult that means roughly:
- ~90 minutes of brisk walking (3.5 mph)
- ~50 minutes of jogging (5 mph)
- ~60 minutes of cycling at moderate pace
- ~75 minutes of swimming
Doing this every day, indefinitely, is brutal. Most people don't sustain it.
Option C: The realistic mix
- Cut 300 kcal from food (skip one snack, switch a takeaway for home cooking, drink less alcohol)
- Add 200 kcal of exercise (a 40-minute walk, three times a week, averages out to ~200/day)
This is what the NHS Weight Loss Plan, NICE guidelines and most UK GPs actually recommend. It's the most sustainable model.
Worked example
Sarah is 38, 5'5", 13 stone (83kg), works at a desk, walks her dog twice a day.
- BMR = ~1,500 kcal (Mifflin–St Jeor)
- Activity multiplier = 1.375 (light)
- TDEE = ~2,060 kcal/day
- Target for 1 lb/week loss: 2,060 − 500 = 1,560 kcal/day
If Sarah hits 1,560 kcal/day for 6 months, she'd lose about 26 lb (nearly 2 stone) — putting her around 11 stone, well into the healthy BMI range for her height.
What 1 lb a week actually looks like over time
| Time | Weight lost |
|---|---|
| 1 month | ~4 lb (about 0.3 stone) |
| 3 months | ~12 lb (about 0.85 stone) |
| 6 months | ~26 lb (1.85 stone) |
| 12 months | ~52 lb (3.7 stone) |
For people starting in the obese category, this kind of trajectory is genuinely transformational — and the slow pace means the weight tends to stay off.
Why faster usually fails
Lose 2 lb a week and the maths still works on paper (1,000 kcal/day deficit). In practice:
- Hunger spikes. You'll be cranky and constantly thinking about food.
- Energy crashes. Workouts get harder, work gets harder.
- Muscle loss accelerates. You end up "skinny fat" — lighter but with worse body composition.
- Adherence collapses. Most people can't sustain 1,000-kcal deficits beyond a few weeks.
- Rebound is almost guaranteed. NHS data show people who lose weight rapidly regain it twice as often as those who lose slowly.
The realistic plan
Week 1–2: Track without changing
Use MyFitnessPal or Nutracheck to log everything you eat for two weeks. No restrictions. This shows you where calories actually come from. Most UK adults are shocked.
Week 3 onwards: Apply the 500-kcal cut
Look at your tracking. The biggest culprits are usually:
- Alcohol (huge contributor in UK adults — 2 glasses of wine = 300 kcal)
- Snacks bought from petrol stations / Pret / coffee shops
- Liquid calories (lattes, smoothies, juices, fizzy drinks)
- Restaurant portions and takeaways
Cut from those before touching home-cooked meals.
Add walking
Aim for 7,500–10,000 steps a day. Adds 200–350 kcal of burn for most UK adults.
Add resistance training
Two short sessions a week (even bodyweight at home) preserve muscle while you lose. NHS resources have free routines.
Weigh weekly, not daily
Same day, same time, before breakfast. Daily weight fluctuates by 2–3 lb just from water and food in the gut — meaningless noise.
What to do when you stall
Plateaus happen. After 2–3 weeks of no movement:
- Re-track honestly. Bites, sips, tastes add up.
- Recalculate your TDEE. Lighter you = lower burn.
- Drop intake by another 100–200 kcal.
- Or take a 1-week diet break at maintenance — it often kicks things back into gear.
The bottom line
1 lb a week = 500 kcal deficit per day. Achievable through food and modest exercise. Slow, unsexy and genuinely effective for the long haul. Use the calculator to get your specific target.
Sources: NHS Weight Loss Plan, NICE clinical guideline CG189, NHS Better Health, British Dietetic Association. This article is general information only — speak to your GP before starting a weight-loss plan if you have any health conditions.