The Importance of Nutrition after Surgery

One of the best, and easiest, things you can do following your surgery is focus on your diet. Following surgery, your body undergoes a state of intense recovery, and some may argue that post-operative nutrition may be more important than rehabilitation.  The body does an amazing job at adapting to different stress and stimuli, but only under the right conditions.  Focusing in on your post-operative nutrition, water, and dietary intake can put you ahead of the curve following your surgery, potentially accelerating your rate of healing and recovery.

In this article, different nutrition and diet strategies will be presented with the intent to give you practical and applicable ideas to help accelerate your rehab.

During the initial physical therapy evaluation, I always ask my patients about their diet.  The answers I have gotten (not always, but more regularly than I’d like) have not only blown my mind, but are also deeply concerning.  Patient’s will literally walk in to their first appointment carrying fast food bags, sugary beverages, and the like.  In a state of extreme healing, your body is literally begging for your help in the recovery process.

The problem is patients typically 1) eat foods high in sugar and calories, (secondary to their post-operative “depression”) and 2) eat more of the foods they already eat.  Now that they’re sedentary, the calorie in:calorie out ratio is highly skewed.  It is not uncommon for people to gain weight (in the form of fatty adipose tissue), and lose a significant amount of muscle mass.  This makes for an insidious combination that will prolong your recovery.

Don’t be this guy.

Wagner et al, out of the Mayo Clinic, reported the rates of reoperation, implant revision or removal, and many common complications after total knee arthroplasty were strongly associated with BMI.

Using prospectively collected data from our institutional total joint registry, the authors analyzed over 22,000 consecutive knees treated with primary total knee arthroplasty (replacement) from 1985 to 2012.  They Found that re-operation and implant revision or removal rates increased with increasing BMI after total knee arthroplasty(4).

  Increasing BMI also was associated with increased rates of wound infection and deep infection per unit of BMI over 35 kg/m2.  A BMI of 35 to 40 kg/m2 (“Obese” BMI) was associated with a higher rate of implant revision for aseptic loosening  and for polyethylene wear compared with a BMI of 18 to 24.99 kg/m2 (“Normal” BMI)(4).

You can calculate your BMI, by adding your height and weight HERE.


While going into depth about macronutrients is not the goal of this discussion, it is important to have some baseline knowledge on the subject.  Macronutrients are the nutrients we get the clear majority of our calories from.  Calories are what give us energy for human movement and physiological processes.


  Macronutrients include Protein (4 kilocalories (kcal) of energy per gram), Fat (9 kcal/gram), and Carbohydrates (4 kcal/gram).  All this means is that for each gram of protein, fat, or carbs that you consume, you ingest 4, 9, and 4 calories, respectively.  The more calories you consume, the more potential energy you have at your disposal.

The problem following surgery is that you are typically in a sedentary state, secondary to pain and discomfort, and you consume the same number of calories.  In its simplest form, if you consume more calories (food) than you burn, your body will store the excess calories (in the form of glycogen in the liver, or sub-dermal adipose tissue (fat)), to be used as fuel later.  Our bodies are amazing at converting and storing “unused energy” so that we may use it the future.  This was a great survival trick humans used when food was scarce, but following surgery it is a huge detriment.



Here, we are referring to someone’s Basal Metabolic Rate (BMR).  Metabolism is the process of your body using energy for the purpose of physiologic functions to maintain homeostasis (and keep you alive).  It makes up roughly 60-65% of your daily calorie burn.  These are the calories you would burn just lying in bed all day…kind of like after a major surgery.  


Thermogenesis literally means heat production, and it is related to the energy your body expends during the metabolic processes related to digestion and conversions of food into usable energy.  Some researchers call this dietary-induced thermogenesis (DIT), or the Thermal Effect of Foods (TEF).  It makes up for roughly 10% of daily calorie expenditure.  This is why some vegetables like celery are considered “negative” calorie foods, because the body expends more energy digesting celery than it gets from the nutrients (or lack thereof) that it contains.


If we have 60% of calorie expenditure coming from BMR, and 10% coming from TEF,
that leaves 30% of daily calorie burn still available.


The remaining calorie expenditure comes from your Non-Exercise Physical Activity (NEPA).  This includes any and all activities you do outside of rest.  Squatting to a chair, walking at low intensity levels around your home, preparing meals, or fidgeting, are all examples of non-exercise activity.

This is where someone post-operatively will run into problems.  Not only is their NEPA affected due to an increase in being sedentary, they also have decreased structured exercise, which helps to burn calories and maintain cardiovascular/musculoskeletal health.

Several studies have looked at the effects of deconditioning.  One study found that in endurance cyclists, four weeks of inactivity resulted in a 20% decrease of their VO2 max(1,2). VO2max is a measure of one’s maximum capacity to take in, transport, and use oxygen during exercise.  If we apply this to someone following a surgery which requires the patient to be non-weight bearing (NWB), we can infer that they will lose a tremendous percentage of their conditioning due to their decreased ability to exercise.

BACK TO NUTRIENTS (and supplements)

We previously touched on the concepts of calories in protein, fats, and carbohydrates.  But there are also several other important nutrients to consider following surgery.



Often missed, but there is no doubt about the importance. HYDRATE!



Leafy greens provide the vitamins, minerals, fiber, and sustenance to improve healing.  They are also very low in relative calories, which may help limit post-operative weight gain. 


Nuts can provide essential fats and fiber.  The key here is to not over consume as these are typically calorie dense. 


Chicken, eggs, fish are a few examples.  The daily recommendation is approximately 0.8 g/kg of body weight.  So, if you are 200 lbs. (91 kg), the goal is to ingest around 80 grams of protein/day. 


The benefits of fiber following surgery are well known.  Fiber is dietary material containing substances such as cellulose, lignin, and pectin, which are resistant to the action of digestive enzymes.  Fiber is what helps keep you “regular,” and can aid in bowel movements.  Following surgery, the body’s central nervous system is slowed secondary to anesthesia and pain medications, which slows down the digestive system and limits waste elimination.  Fiber can aid in your digestive health following surgery.

 Orthopedic patients are at an even greater risk of becoming constipated due to restrictions imposed on their mobility. 

Prescription of narcotic analgesics, particularly those containing codeine, increases the potential for constipation.

Dietary fiber, fluid, and exercise are known to be effective means of treating and preventing constipation…As well, its ingestion must be accompanied with adequate water intake.

Ouellet et al. Dietary Fiber and Laxation. Clinical Nursing Research. Nov 1996;5(4):428-440.


Amino acids are the “building blocks” of proteins.  You may want to consider supplementation with BCAA (branch-chain amino acids) to decrease post-operative muscle atrophy.



Sugar consumption has been linked to obesity, diabetes, and delayed healing.


Nicotine in tobacco delays healing.  Don’t do it.


They market “recovery” but may cause more harm than good due to the high levels of refined sugar.  Remember, these are meant during a vigorous bout of exercise, not sitting on the couch after surgery.


High calorie, low nutrient.  Not much more explanation needed.


  You are in total control.  The best thing you can do is plan.  There is great, free, information on websites like and  Make a food journal, or use one of the aforementioned sites food logs to help keep you organized and on track.

Plan! Being prepared will help keep you on track.



Post-injury or post-surgery, the body is begging for proper nutrition.  Why would you sabotage your body and physical health?  Even if this article is unclear to you, even children have an idea of what “healthy” and “unhealthy” foods are.  For more in depth recommendations, please consult a registered dietitian.

  1. Coyle E.F., Martin W.H. 3rd, Sinacore D.R., et al. Time course of loss of adaptations after stopping prolonged intense endurance training. Journal of applied physiology: respiratory, environmental and exercise physiology, 1984 Dec;57(6):1857-64.
  2. Madsen K., Pedersen P.K., Djurhuus M.S., et al. Effects of detraining on endurance capacity and metabolic changes during prolonged exhaustive exercise. Journal of Applied Physiology, 1993 Oct;75(4):1444-51.
  3. Ouellet et al. Dietary Fiber and Laxation. Clinical Nursing Research. Nov 1996;5(4):428-440.
  4. Wagner et al. Effect of Body Mass Index on Reoperation and
    Complications After Total Knee Arthroplasty. J Bone Joint Surg Am. 2016;98:2052-60.