Post-amputation weight gain; why it happens & what to do?

Most major injuries result in unwanted long-term weight gain, but an amputated limb presents its own unique challenges.  For those with a lower limb amputation (trans-tibial or trans-femoral), 40% will go on to gain at least 10% of their body weight over the next ~2 years and will double their risk of becoming obese. 

Weight changes can negatively affect the function of prosthetic limbs and can also impact socket fit.  In addition, a body weight of over 100kg generally exceeds the weight limit for most prosthetic components and can make someone ineligible for osseointegration surgery. These challenges are in addition to the more general risks associated with becoming overweight/obese, such as increased risk of musculoskeletal pain, osteoarthritis, cardiovascular disease, type 2 diabetes, increased risk of falls and slow healing wounds.

If you have gained more than 10% of your body weight since your amputation (that means if a 70kg person has gained more than 7kg), ask your GP to refer you to a dietitian for additional support.  Dietitians can be accessed through the NHS and/or private dietitians.

Why does weight gain happen after an amputation & what can you do?

1 - Loss of Muscle Mass

After a major injury, most people will lose muscle mass when they are in hospital.  This is primarily due to high levels of inflammation in the body (from the trauma itself), being limited on what (if any) physical activity you can do and/or having an inadequate protein intake while in hospital.  Muscle is what burns the calories, so the less muscle mass you have, the slower your metabolic rate is going to be and the fewer calorie you will burn. 

Most people are completely unaware of these changes and revert back to their pre-injury eating habits without realising this will likely result in weight gain.  Other times, someone may be put on a high calorie diet while in hospital (when calorie requirements increase briefly), and then aren’t told this is only meant to be implemented short-term.  This can also result in weight gain.

People with an amputation (especially a lower limb amputation) have an additional consideration.  When your limb is removed, the surgeon removes muscle along with it.  This loss of muscle will reduce your calorie needs even more.

“Recommendation:
Make sure you eat adequate protein while you are in hospital and once you get home. High protein foods include high protein yogurts, milk, fish/seafood, chicken, eggs, soy and lean red meat. Eating mostly toast, sandwiches, cereal and snack foods will not provide enough protein for most people.

Start moving and doing physio, as soon as the surgeon says it is OK to do so. When it comes to muscle mass, you start losing it within 24 hours of being bedbound. If it’s safe for you to be moving, you need to be up and out of bed ASAP. ”

2 - Not Checking your weight

After an amputation, many people switch to looser fitting clothes to accommodate their new body shape, and this can make it very difficult to pick up on subtle changes in weight.  Monitoring your weight is key!

If you can’t stand unsupported on a regular stand-on scale, what options do you have for weighing yourself?  Seated, hoist and wheelchair scales do exist, but finding one can be a challenge.  Some physio offices and prosthetic clinics do have wheelchair scales, but not all clinics provide this service.  If you can’t borrow a scale, you might want to purchase your own scale or alternatively, use a form-fitting article of clothing to monitor for weight changes.

“Recommendations:
Weigh yourself a minimum of once per month.

If you need a seated or wheelchair scale, check with your local physio or prosthetic clinic first.

If you have a ceiling track hoist, make sure you get one with an integrated scale.”

3 - Being less physically active

A lower limb amputation usually reduces someone’s physical activity levels, even in people who were very active pre-injury. This is often due to delays in getting a prosthetic limb fitted, delays due to skin healing of the stump, reduced movement due to pain and/or low mood interfering with motivation.

Regardless of the reason, less physical activity means lower calorie requirements and a higher chance of gaining weight.

“Recommendations:
Get physio involved as soon as possible and do your exercises!

Consider what types of physical activity would bring you the most enjoyment outside of formal physio sessions. Gym? Kayaking? Wheelchair rugby?”

4 - Eating too many calories

Once you are discharged home after a major trauma, you need to be very careful with what you eat.  Take aways, fast food, food deliveries and snack foods will be very tempting, but these need to be limited at first until you can closely monitor your weight.  Getting healthier pre-made food or ready meals from the supermarket will usually be a better option.  You also need to be alert to any comfort eating due to stress, boredom, anxiety or depression and find other ways to manage your emotions. 

“Recommendations:
Access healthier food choices through either online food shopping or healthier meal delivery options.

Get Occupational Therapy involved as soon as possible to discuss kitchen adaptation.

Access psychological support if comfort eating is becoming an issue.

Make lean protein and vegetables the basis of your meals and dial back on the intake of refined carbohydrates (e.g. less bread, biscuits and potatoes).”

5 - Drinking more alcohol

It’s common for alcohol consumption to increase within 3 months of an amputation.  This happens when alcohol becomes an easy way to socialise with peers and/or when alcohol is used as a coping mechanism for anxiety, depression, boredom and/or chronic pain.  Regardless of the reason, alcohol can provide a lot of calories (with no nutritional value) so you need to limit the amount you have.

“Recommendations:
Keep alcohol intake to a minimum. Public Health England recommends no more than 14 units of alcohol per week, but even that could provide too many calories for someone with an amputation.

Choose low-calorie, non-alcoholic options as much as possible (e.g. alcohol-free beer; alcohol-free gin and slimline tonic).”

6 - Side effects of medication

Certain medications can affect appetite and result in weight gain (e.g. gabapentin, pregabalin and mirtazapine).  Monitor your weight very carefully any time you start a new medication and contact the GP if you notice a problem.

“Recommendations:
Regularly ask the GP to review your medication to see if anything can be discontinued.

If your weight is increasing, ask the GP to prescribe an alternative medication.
”

Source: Sheri Taylor, Specialist Rehab Dietitian, www.specialistnutritionrehab.co.uk.