For most adults, a safe and sustainable rate of weight loss is about 0.5-1 kg (1-2 lb) per week, which works out to roughly 0.5-1% of your body weight per week. Health services such as the NHS and the CDC give very similar guidance. You may lose faster in the first week or two, mostly water, and slower as you get closer to your goal.

That range isn't arbitrary caution. Losing at that pace makes it easier to keep muscle, get enough nutrients, avoid constant hunger and, most importantly, keep the weight off afterwards.

Why "per cent of body weight" is the better rule

A fixed number like "1 kg a week" means very different things for different people. For someone who weighs 130 kg it's a moderate pace. For someone who weighs 60 kg it's very aggressive. Expressing the target as a percentage scales it to you:

  • 60 kg person: 0.3-0.6 kg per week
  • 80 kg person: 0.4-0.8 kg per week
  • 100 kg person: 0.5-1.0 kg per week
  • 130 kg person: 0.65-1.3 kg per week

If you're close to a healthy weight already, aim for the lower end. If you have more to lose, the upper end is usually fine, and early weeks may be faster still.

What happens in the first weeks

Many people see 1.5-3 kg disappear in the first one or two weeks of a diet and assume that's the pace they'll keep. It isn't. Part of that early drop is water: when you eat fewer calories, and especially fewer carbohydrates, your body uses some of its stored glycogen, which is held together with water. Less food in your digestive system also weighs less.

None of this is a problem. Just don't use week one as the yardstick. Judge your pace from week three onwards, using weekly averages rather than single weigh-ins. Our guide on how often to weigh yourself explains a simple routine.

What it takes to hit each pace

Using the common approximation that 1 kg of body fat holds about 7,700 kcal:

  • 0.25 kg per week — about 275 kcal per day below maintenance
  • 0.5 kg per week — about 550 kcal per day below maintenance
  • 0.75 kg per week — about 825 kcal per day below maintenance
  • 1 kg per week — about 1,100 kcal per day below maintenance

These are rough figures. Real-world results vary because your body adapts and because nobody's intake is perfectly measured. But they show why a 1 kg per week pace is only realistic for people with a fairly high maintenance intake: a smaller person simply can't cut 1,100 kcal a day without dropping to an intake that's too low. If you don't know your maintenance number yet, start with How to Calculate Your Daily Calorie Needs.

Why faster isn't better

Crash diets and very low-calorie diets can produce dramatic numbers for a few weeks. The trade-offs:

  • More muscle loss. With a large deficit, a bigger share of the weight lost can come from lean tissue, which you want to keep for strength, metabolism and how you look.
  • Nutrient gaps. It's hard to get enough protein, fibre, vitamins and minerals when you're eating very little.
  • Hunger and fatigue. These make workouts worse and binges more likely.
  • Gallstones. Rapid weight loss is a known risk factor for gallstones.
  • Regain. Rules you can't live with eventually stop, and the old habits return with the weight.

Very low-calorie diets do have a place, but under medical supervision, not as a self-made plan.

How to lose weight at a safe pace

  1. Set a moderate deficit. Start with 300-500 kcal below maintenance. Read Calorie Deficit Explained for ways to create it without constant hunger.
  2. Eat enough protein. Around 1.2-2.0 g per kg of body weight per day helps protect muscle and keeps you full.
  3. Strength-train at least twice a week. It tells your body to hold on to muscle while you lose fat. Bodyweight training at home works fine.
  4. Move every day. The WHO recommends 150-300 minutes of moderate activity a week for adults. Walking counts.
  5. Sleep 7-9 hours. Poor sleep makes hunger and cravings harder to manage.
  6. Check the trend every 2-3 weeks. Losing faster than 1% a week after the first fortnight? Eat a little more. Nothing moving for three weeks? Trim 100-200 kcal or tighten your tracking.

A realistic timeline

Here's what a sustainable plan might look like for someone starting at 90 kg who wants to reach 80 kg, aiming for around 0.5-0.7 kg a week:

  • Weeks 1-2: 1.5-2.5 kg drop, mostly water and gut content
  • Weeks 3-10: steady loss averaging roughly 0.5-0.7 kg per week, with some weeks flat and some faster
  • Weeks 10-18: pace often slows as the body gets lighter; small adjustments to intake or activity keep it moving
  • Around month 4-5: goal reached, followed by a gradual move up to maintenance calories

Ten kilos in four to five months might sound slow, but it's a pace most people can actually finish, and finishing is what counts.

When to talk to a doctor

See a doctor before starting if you have diabetes, heart, kidney or liver disease, take medication that affects weight or blood sugar, are pregnant or breastfeeding, or have a history of disordered eating. Also see one if you're losing weight without trying, as unexplained weight loss can be a sign of an underlying health problem.

Tracking your pace

The easiest way to stay in the safe range is to see your trend. FIThim lets you choose a weekly pace during setup, builds your calorie target around it, and shows your logged weight on a chart against your goal, so you can tell quickly whether you're on track, too fast or stuck. If you are stuck, read Weight Loss Plateau before making big changes.

FAQ

Is losing 2 kg a week safe?

For most people, no, apart from the first week or two when water loss inflates the number. Over the longer term, 2 kg a week usually requires a very large deficit and should only happen under medical supervision.

How much weight can I lose in a month?

At 0.5-1% of body weight per week, roughly 2-4% of your body weight in a month is realistic. For an 80 kg person that's about 1.6-3.2 kg, with the first month often a little higher because of water loss.

Why am I losing weight slower than the calculator says?

Calculators are estimates, intake tends to be under-counted, and water retention can mask fat loss for a week or more. Look at the average over at least three weeks before deciding the plan isn't working.

Is slow weight loss easier to keep off?

Slower loss is generally linked with habits that are easier to maintain, which is the main factor in keeping weight off. What matters most is that the way you eat while losing weight is something you can keep doing afterwards.