Gastric Bypass Weight Loss
Before discussing weight loss results, it is important to understand how weight loss after surgery is described.
The most common way to describe weight loss after surgery is by percent of excess weight lost (%EWL). Excess weight is the amount of weight over ideal weight. Ideal weights are derived from the Metropolitan Life Insurance Company height/weight tables.
See the table at the bottom of this page for a tabulation of ideal weights.
Gastric Bypass Weight Loss – Our Results
Dr. Oliak’s gastric bypass weight loss statistics are as follows: average 78% EWL (excess weight loss) at 2 years after surgery, average 72% EWL at 5 years after surgery, and average 66% EWL at 10+ years after surgery.*
Dr. Oliak’s gastric bypass weight loss statistics are better than the industry average gastric bypass weight loss statistics (see discussion below).*
Gastric Bypass Weight Loss – Our Statistics
76% EWL after 1 year
78% EWL after 2 years
75% EWL after 3 years
72% EWL after 5 years
74% EWL after 7 years
66% EWL after 10-13 years* The weight loss results above are averages. Individual patients can lose more or less weight than the average. Our %EWL (percent excess weight loss) statistics are for all gastric bypass operations (>1000) completed 2002-2017.
Gastric Bypass Weight Loss – Published Studies
There have been 100s of studies published on gastric bypass weight loss, by 100s of surgeons. The quick summary of the published literature is that gastric bypass surgery is highly effective for weight loss, but the amount of average weight loss varies depending on the surgeon and program.*
Because the published studies are quite variable in what they report, several researchers have published review studies. Review studies compile data from numerous other studies to get a more accurate big picture view.
Livingston et al published a review study in 2014 that compiled data from 11 published gastric bypass weight loss studies. Of note, only the studies with the highest quality weight loss data were included. Livingston reported gastric bypass weight loss to be 68% EWL at 2 years after surgery, and 65% EWL at 3-5 years after surgery.*
Livingston also reported the range of average %EWL results between the different studies, which means between the different surgeons/programs. At 2 years after surgery, the range of weight loss outcomes between the different surgeons/programs was reported to be 51-78% EWL. At 3-5 years, the range was reported to be 58-68% EWL.
This variation between the different studies is significant. The difference between 51% EWL and 78% EWL is about 30 pounds for a typical patient who starts out 100 pounds over ideal weight. This review study shows that some gastric bypass surgeons/programs achieve better weight loss outcomes than others.*
Long-Term Gastric Bypass Weight Loss – Published Studies
There have been many fewer published studies on long-term weight loss (10+ years) after gastric bypass, so the data are not as robust as for short-term weight loss (1-5 years).
Good long-term gastric bypass weight loss studies include Pories et al, Obeid et al, and Higa et al. These 3 studies report average weight loss to be 55-59% EWL at 10 years after gastric bypass, with an overall average of 57% EWL.*
Gastric Bypass Weight Loss – Our Statistics vs. Published Literature
|Time after surgery||
Dr. Oliak’s %EWL (>1000 operations)*
Published literature %EWL
Published literature %EWL range
* The weight loss results above are averages. Individual patients can lose more or less weight than the average. Dr. Oliak’s %EWL (excess weight loss) statistics are for all gastric bypass operations (>1000) completed 2002-2015. Published literature %EWL statistics are from Livingston et al for 2yr and 3-5yr data, and from Pories et al, Obeid et al, and Higa et al for 10yr data.
* The weight loss statistics on this page are averages. Individual patients can lose more or less weight than the average.
Ideal Body Weights for Men and Women
|Women (height ft./in.)||Ideal Weight* (pounds)||Men (height ft./in.)||Ideal Weight* (pounds)|
* Ideal weights above are derived from the Metropolitan Life Insurance Company height/weight tables, 1983, New York, New York. Ideal weights above are the midpoint weights from the medium frame size weight range. Weights include 3-5 pounds of clothes. Heights assume no shoes.