Most traumatic injuries result in unwanted long-term weight gain.  However, an amputated limb presents its own unique challenges when it comes to managing weight.  For those with a lower limb trans-tibial or trans-femoral amputation, 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. 1, 2, 3

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 usually makes someone ineligible for osseointegration surgery.4, 5  These challenges are in addition to the more generalised risks associated with becoming overweight/obese, such as increased risk of musculoskeletal pain, osteoarthritis, cardiovascular disease, type 2 diabetes, increased risk of falls, impaired wound healing and diminished quality of life.2

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

1. Changes to body composition.

Almost all traumatic injuries result in a rapid loss of muscle mass.  This is primarily due to high levels of inflammation in the body (immediately post-injury), periods of immobility, reduced levels of physical activity overall and/or an inadequate protein intake while in hospital.  Muscle is what burns the calories, so the less muscle mass someone has, the slower their metabolic rate is going to be and the fewer calories they will burn.  Most clients are completely unaware of these changes and revert back to their pre-injury eating habits without realising this will likely result in weight gain.  In other cases, clients are put on a high calorie diet in the early stages of their hospitalisation (when calorie requirements increase briefly), and then aren’t told this is only meant to be implemented short-term.  These clients then carry on eating a high calorie diet without realising their requirements have now changed and end up gaining weight.

People with an amputation (especially a lower limb amputation) have an additional consideration, and need to account for the muscle that is lost alongside the removed limb, as this will reduce their calorie requirements even more.

Recommendation:

• Make clients aware of these metabolic changes as soon as they are discharged from hospital.  This will allow them to adjust their food intake accordingly.

2.  Lack of weight monitoring

Without regular monitoring post-injury, body weight can creep up without people being aware.  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.

Unless someone can stand unsupported on a regular stand-on scale, the challenge then becomes getting an accurate weight for them.  If they require the use of a seated or wheelchair scale, these are not always readily accessible.  Some physio offices and prosthetic clinics do have wheelchair scales and are willing to let clients and non-clients use them, but not all clinics provide this service.  Furthermore, if clients are not yet in their “forever home,” this means they may not yet have the space or money for a wheelchair scale and may not have ceiling track hoists installed with integrated scales.  Trying to get these clients weighed then becomes extremely challenging in the interim and clients may gain a lot of weight before anyone notices.

Recommendations:

• Support clients to access wheelchair scales in their community or to purchase their own scales as soon as they are discharged from hospital. For suggestions on appropriate weighing scales, go to our article on weighing wheelchair-bound, bedbound and bariatric clients.
• Encourage clients to weigh themselves a minimum of once per month.

3. Reduced levels of physical activity

Even in people who were very active pre-injury, research has found that they are much less physically active after a lower limb amputation.2  This often relates 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.2

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

Recommendations: 

• Help clients engage the services of both physiotherapists and occupational therapists as early as possible, to facilitate increased physical activity as both a therapeutic and leisure-time pursuit.
• Consider whether clients are open to a gym membership and/or personal trainer or whether they would prefer less traditional activities like kayaking or wheelchair rugby.

4.  Eating too many calories

After hospital discharge, many clients revert back to their pre-injury eating habits, without accounting for their greatly reduced metabolic rate.  Some clients may even start eating more than what they did pre-injury, as a way of coping with stress, anxiety or depression.  Clients may also experience challenges with food preparation, especially if their kitchen cannot accommodate their new needs or if they are dealing with pain or fatigue.  In all cases, the temptation is for clients to consume more fast food, take away, ready meals and/or snack foods, and this can result in weight gain.  It’s important that case managers, solicitors and allied health professionals are alert to these changes so that a dietetic referral can be made as soon as possible.

Recommendations:

• Support clients to access healthier food choices through either online food shopping or healthier meal delivery options. Check out our article on top 15 healthier convenience foods for ideas. 
• Get Occupational Therapy involved as soon as possible to discuss kitchen adaptation.
• Be alert to clients who may be comfort eating and access psychological support if required.
• Encourage clients to make lean protein and vegetables the basis of their meals and to dial back on their intake of refined carbohydrates (e.g. less bread, biscuits and potatoes).

5.  Drinking more alcohol

It’s common for alcohol consumption rates to jump from 33% to 72% within 3 months of an amputation.6  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.6  Regardless of the reason, alcohol can provide a lot of calories (with no nutritional value) and thus result in unwanted weight gain.

Recommendations: 

• Be sure to ask clients about their alcohol intake on a routine basis to assess for any increases. Public Health England recommends no more than 14 units of alcohol per week.7
• Encourage non-alcoholic options as much as possible (e.g. alcohol-free beer; alcohol-free gin and slimline tonic).

6.  Side effect of medication

After an amputation, medication may be prescribed for neuropathic pain (e.g. gabapentin and pregabalin) and/or depression (e.g. mirtazapine) which can also affect weight.  Changes to appetite regulation can occur as a side effect of these medications and result in unwanted weight gain.  For more information, check out our article on medication-induced weight gain.

Recommendations: 

• Ask the GP to review medication on a regular basis so that clients are only on what they really need.
• If weight is increasing, ask the GP whether alternative medication is available.

Weight gain after an amputation often has a multifactorial root cause.   A referral to a dietitian is recommended if someone has gained more than 10% of their body weight unintentionally since their amputation.  To refer a client for specialist dietetic input and assessment, contact Specialist Nutrition Rehab at 0121 384 7087 or info@specialistnutritionrehab.co.uk.

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