Bariatric surgery is a major step towards better health for individuals battling obesity, especially when other weight loss methods have been unsuccessful. It's natural to have questions about the weight loss outcomes following surgery. This article is here to address those concerns and provide clarity on what to expect.
Bariatric surgery is widely regarded as a highly effective option for individuals with obesity, offering significant and long-term weight loss. However, it’s important to recognize that weight loss after surgery can vary greatly from person to person. Factors influencing weight loss outcomes include pre-surgery BMI, age, gender, the specific surgical procedure, and adherence to post-surgery guidelines such as diet and exercise. On average, patients can expect to lose approximately 30% of their total body weight by 9 months post-surgery and around 75% of their excess body weight within 2 years.
That said, each person’s journey is unique, and weight loss can differ based on the type of surgery performed, as outlined below:
- Gastric band: Up to 50-60% of excess body weight over 2 years
- Gastric sleeve: Up to 50-70% of excess body weight over 2 years
- Gastric bypass: Up to 60-80% of excess body weight over 1 year
- Gastric balloon: 10-20% of total body weight within 6 to 12 months
Calculating your excess body weight (EBW)
To estimate the approximate weight loss you can expect after bariatric surgery, it's essential to first calculate your excess body weight (EBW). EBW represents the amount of weight you carry above what is considered a healthy weight for you. While traditional guidelines suggest a BMI of less than 25 kg/m² as a general target, it's important to remember that BMI is just one of many health indicators, and each person's optimal health varies. However, using a BMI of 25 kg/m² as a benchmark can be helpful in determining your ideal body weight based on your height, and subsequently, your EBW.
Below is a step-by-step guide to help you calculate this:
-
Find out your current weight (kg) - keep this figure to one side for now
-
Measure your height (m) and then times it by itself (this is your height squared)
-
Calculate: 25 (ideal BMI) TIMES BY your height squared = Your body weight at a BMI of 25
-
Calculate: Current weight (kg) MINUS ideal body weight (kg) = excess body weight (kg)
-
Calculate: 50% or 75% of your excess body weight
- 50%: 0.5 x excess body weight (kg)
- 75%: 0.75 x excess body weight (kg)
Working example:
A patient weighing 140 kg with a height of 1.67 m (5ft 5).
|
|
Steps |
Example |
|
1 |
Identify your current weight |
140 kg |
|
2 |
Measure your height |
1.67 m |
|
3 |
Calculate your body weight at a BMI of 25 |
25 (BMI) x (1.67 x 1.67) = 83.5 kg |
|
4 |
Calculate EBW |
140 kg (current weight) – 83.5 kg = 56.5 kg |
|
6 |
Calculate 75% of your EBW |
0.75 x 56.5 = ~42 kg (target weight loss) |
This person can therefore expect to lose around ~42 kg (around 6 and a half stone) over 2 years if they had a gastric bypass. However, this is a guide and weight loss could be more or less than estimated depending on lifestyle factors and genetics as previously discussed.
Calculating your weight loss target
Setting a weight loss target can be very motivating. A good initial goal is to aim for a BMI of 30 kg/m². You can calculate your target weight for this BMI by multiplying 30 by your height in meters squared (30 x height²). While some individuals may achieve a BMI of 25 kg/m² (representing 100% excess weight loss), reaching this level requires significant effort and dedication. Success will largely depend on your commitment to post-operative guidelines, which may include:
- Regular physical activity
- Adherence to post-operative nutritional guidelines
- Compliance with prescribed supplements to maintain energy levels
- Managing emotional eating, which may involve consultations with a psychologist
Everyone’s weight loss journey is unique, so it’s essential to focus not only on the amount of weight you’re losing but also on your overall improvements in health. While some individuals may experience a dramatic drop in weight shortly after surgery, for others, the process may take longer. It’s important to keep in mind that significant weight loss immediately after surgery may be due to the loss of water, glycogen, and salt, rather than body fat.
Another crucial factor to consider is changes in body composition. Muscle is denser than fat, and with the lifestyle changes you’ll be making post-surgery, you may lose fat while gaining muscle. This can result in a slight increase or plateau in your scale weight, which is perfectly normal. Daily fluctuations in weight are also common, as weight loss is not a linear process. Focusing on your weight trends over time will give you a more accurate picture of your progress.
Sustainable weight loss is the key to long-term success, and committing to the lifestyle changes mentioned above is crucial. Remember, it’s important not to compare your weight loss journey with others; each person’s path is individual. Focus on your progress and celebrate the improvements in your health as you continue on your journey.