Most people lose a large part of their excess weight in the first 12–18 months after a gastric sleeve, with the fastest loss early on. On average that is about 60–70% of excess weight, but the range between individuals is wide. Knowing the usual pattern helps you set realistic expectations and stay calm when the scales stop moving for a while.
What does “excess weight” mean?
Bariatric results are usually expressed as a percentage of excess weight: the weight above a healthy BMI of 25. For example, if you are 1.70 m tall and weigh 120 kg, a BMI of 25 corresponds to about 72 kg, so your excess weight is about 48 kg. Losing 60–70% of it would mean losing roughly 29–34 kg.
This is why two people can have equally good results but very different numbers on the scales: someone with a higher starting weight usually loses more kilograms, while the percentage may be similar.
A typical timeline
| Time after surgery | Typical excess weight lost (rough guide) | What is happening |
|---|---|---|
| Month 1 | About 10–15% | Very small portions, liquid and puréed diet, some fluid loss |
| Month 3 | About 25–35% | Steady loss as you move to normal textures |
| Month 6 | About 40–50% | Loss continues but more slowly |
| Month 12 | About 55–65% | Most of the loss has happened |
| Months 12–18 | About 60–70% | Loss slows and levels off |
| Months 18–24 | Stable | Weight settles; the focus is on keeping it |
Some people lose more and some less. A lower starting BMI often means a higher percentage of excess weight lost, while a very high starting BMI often means more kilograms lost but a lower percentage.
The first three months
Weight comes off quickly at first because you eat very little while on liquids and puréed food, and part of the early loss is fluid. This phase can also bring tiredness, light-headedness or hair shedding, usually temporary and linked to the fast change. Getting enough protein and fluid, and taking your vitamins, helps your body cope.
Plateaus: why the scales stop moving
Almost everyone has periods of days or weeks when their weight barely changes. A common one appears around weeks 3–4, when the body adjusts to the sudden drop in food and holds on to water. Further plateaus often come later in the first year. They are a normal part of the process, not a sign that the operation has failed.
- Do not cut your food further. Eating too little protein slows recovery and can mean losing muscle.
- Check the basics: protein first, enough fluid, no grazing and no calorie-rich drinks.
- Move more, gradually. Walking every day and, later, strength training help protect muscle.
- Measure more than weight. Clothes, a tape measure and how you feel often change before the scales do.
- Talk to your dietitian if a plateau lasts more than a few weeks.
What affects how much you lose
- Your starting weight and BMI
- Age, sex and how active you are
- Conditions such as type 2 diabetes, thyroid problems or polycystic ovary syndrome, and some medicines
- How closely you follow the diet stages and keep up protein and fluids
- Sleep, stress and your relationship with food
- Regular follow-up with your dietitian and team
Looking after your body while you lose weight
Rapid weight loss is a big change for your body. A few habits make it healthier and help you feel better along the way:
- Protect your muscle. Protein at every meal and regular strength exercise, once your surgeon allows it, help make sure that most of the weight you lose is fat.
- Expect some hair shedding. Many people notice thinning hair between about months 3 and 6. It is usually temporary and improves as weight loss slows, especially with enough protein, iron and zinc.
- Look after your mood. Big changes in body and eating can bring mixed emotions. Talk to your team if you feel low, anxious or worried about food.
- Keep your follow-up appointments. Regular contact with your dietitian and blood tests at the intervals you were given help catch problems early.
Comparing yourself with other patients is natural but rarely helpful. People start from different weights, lose at different speeds and reach their stable weight at different times. Your own trend over months says much more than a single week on the scales.
After the first two years
Once your weight has settled, the work shifts from losing to keeping. Some regain in the years after surgery is common, and the sleeve can stretch a little over time if large portions become a habit again. Small meals eaten slowly, regular activity, ongoing vitamins and an annual check-up help you hold on to your result. If your weight starts rising steadily, contact your team early: it is easier to correct a small change than a large one.
Loose skin is common after major weight loss. Once your weight has been stable for some months, body contouring such as a tummy tuck, arm lift or thigh lift can be discussed with a plastic surgeon.
When to call a doctor
Fast weight loss is expected, but some symptoms are not. Contact your team if you cannot keep food or fluids down, feel faint or very weak, notice numbness or tingling in your hands or feet, or have persistent vomiting. These can be signs of dehydration or a vitamin deficiency that needs prompt treatment.
Our gastric sleeve page explains who the operation suits, how it works and what the follow-up with our dietitian includes after you return home.
Frequently asked questions
On average about 60–70% of your excess weight within 12–18 months. Individual results vary with your starting weight, health and how you eat and move afterwards.
Often about 10–15% of their excess weight, partly because of the liquid diet and some fluid loss. The pace then slows gradually.
Plateaus are normal, often around weeks 3–4 and again later. Keep protein and fluids up, avoid grazing and liquid calories, stay active and speak to your dietitian if it lasts more than a few weeks.
Most of the loss happens in the first 12 months and it levels off between about 12 and 18 months. Weight is usually stable by around 18–24 months.
Some regain over the years is common. Small portions, regular activity, ongoing follow-up and early contact with your team if your weight rises help you keep your result.
