Expected weight loss
Einstein Bariatrics - Why Surgery
How much weight loss should I expect?
Weight loss after bariatric surgery is described as Percent Excess Weight Loss (%EWL). Excess weight is defined as a person’s actual weight minus their ideal body weight (IBW). IBW can be estimated by the formula:
- IBW for Men = 106 + 6 * (height in inches - 60)
- IBW for Women = 100 + 5 * (height in inches - 60)
Example:
- So, for a 5 ft. 5 in. woman, her IBW = 100+5*(65 - 60) = 125 pounds
If that woman weighs 325 pounds, her excess weight is 200 pounds (325 - 125 = 200).
If that woman loses 100 pounds, she has lost 50% of her excess weight (%EWL = 50%).
So, Jane Doe is 5 ft. 5 in. and weighs 325 pounds has a gastric bypass. Jane would be expected to lose 160 pounds two years after her surgery. However, she could lose as much as 190 pounds, or as little as 120 pounds. There is one predictive factor in guessing how much weight a person will lose. Patients who are very heavy and patients that are only slightly overweight, often lose weight at a predictably different rate. For instance, a patient who weighs 600 pounds, will never achieve a weight close to ideal with any bariatric operation. That person may lose 300 pounds, losing 60 percent of excess weight. Furthermore, a patient who weighs only 220 pounds would be expected, on average to lose a higher percentage of excess weight that a person weighing 320 pounds. That is, the thinner you are, the more likely you can achieve a weight closer to your ideal.
After a gastric bypass, the reported long-term weight loss varies from person to person. Therefore, we can only estimate the amount of weight loss. Also, keep in mind that many weight loss operations, including the gastric bypass, have significant weight loss in the short term. Long-term weight loss is much more important. On average, the %EWL after six months, one year and two years will be 50, 70 and 80 percent. The average patient is female with a BMI of 48. There is significant variation, such that 95 percent of people will have lost between 95 and 60 percent of excess weight at two years.
It is normal and expected to gain some weight back after two years. The amount of weight regain is difficult to predict. One person may not regain any weight; another may regain 30 or more pounds. On average, patients regain 10 to 15 percent of their excess weight back in the long term.
The weight loss is more variable and, on average, not as much after the adjustable gastric band. In our experience of more than 200 patients, patients lost 40 to 45 percent of their excess weight. The variation in weight loss is considerable. Some patients lose a tremendous amount of weight, while others, unpredictably, lose little.
This page last updated on 2007-09-24 10:48:17