Comprehensive Calculator Guide
This calculator estimates your weight in the months after a sleeve gastrectomy, from your excess weight and averages in published studies. At 130 kg and 170 cm, excess weight is 57.8 kg above the BMI-25 weight; about 65% of it typically goes in a year — 37.5 kg — bringing you to around 92.5 kg. It shows the expected weight at 3, 6, 12, 18 and 24 months.
Excess weight loss and why results vary
Bariatric teams measure results as the share of excess weight lost, the gap between your starting weight and the BMI-25 weight for your height. Published series average roughly 35% at 3 months, 50–60% at 6, 60–75% at a year, then level off by 18–24 months; the calculator uses 35%, 52%, 65% and 68%.
People starting at very high BMIs often lose a smaller share, though more kilos. Younger, active people who keep to the diet and follow-up do better, and some weight can return after year two if old habits do.
How to Use
- Enter your weight before surgery and your height.
- Enter the months since surgery (1–24).
- Press “Estimate my weight” to see excess weight, expected loss and your weight over the months.
Formula Used
Excess = weight − 25 × height (m)² | Expected loss = excess × typical share for that month
Practical Examples
- Example 1
- 130 kg, 170 cm, 12 months: excess 57.8 kg, loss 37.5 kg, weight 92.5 kg, BMI 32.
- Example 2
- 115 kg, 160 cm, 6 months: excess 51 kg, loss 26.5 kg, weight 88.5 kg.
Important Tips
- Eat protein first at every meal and take the prescribed supplements.
Common Mistakes to Avoid
- Drinking sugary drinks, which slip through easily and stall the loss.
Frequently Asked Questions
- How much weight do you lose after a gastric sleeve in a year?
- Typically 60–75% of excess weight; the calculator uses 65%.
- When does weight loss stop after a sleeve?
- Usually between 18 and 24 months.
- Can weight come back?
- Some can, if old habits return; follow-up and exercise help prevent it.