Your nutritional status and body weight are among the most modifiable factors that influence your surgical outcome. Preparing well — in terms of what you eat, how you manage your weight, and how you optimise your nutritional reserves — can meaningfully improve both your readiness for surgery and the quality of your recovery.
Why Body Weight Matters
Elevated BMI is associated with higher complication rates after joint replacement surgery. These include increased infection risk, wound healing difficulties, greater anaesthetic complexity, and higher revision rates. While joint replacement can be performed safely in patients with a high BMI, the risk profile is meaningfully elevated.
I discuss weight with my patients not to discourage surgery, but because weight loss — even modest amounts — can produce a measurable improvement in surgical risk. A reduction of 5–10% of body weight before surgery can lower complication rates, reduce surgical difficulty, and improve the longevity of the implant. For patients with a BMI above 40, I may recommend a dedicated weight management programme before proceeding to surgery.
"Even modest weight loss before surgery can meaningfully change your risk profile and the quality of your outcome."
— Dr Chien-Wen LiewProtein, Vitamins, and Healing
Beyond weight, your nutritional status — specifically your protein intake and micronutrient levels — has a direct impact on wound healing, muscle recovery, and immune function in the weeks following surgery. Patients who are malnourished or protein-deficient going into surgery consistently show slower recovery, poorer wound healing, and higher risk of infection.
In the weeks before surgery, I encourage patients to focus on adequate protein intake. A general target is 1.2–1.5 grams of protein per kilogram of body weight per day. This supports muscle maintenance during the recovery period and provides the building blocks for tissue repair. Good protein sources include lean meats, eggs, legumes, dairy, and fish.
Vitamin D deficiency is common in South Australia, particularly in older adults, and is associated with impaired bone and muscle function. If you are deficient, supplementation before surgery is advisable. Iron levels should also be checked pre-operatively — anaemia at the time of surgery increases transfusion risk and slows recovery.
Preparing Your Body Before Surgery
Prehabilitation — a structured programme of exercise, dietary optimisation, and medical preparation in the weeks before surgery — is supported by evidence as a strategy to improve surgical outcomes. Patients who engage in prehabilitation consistently show faster return to function and shorter hospital stays.
Dietary prehabilitation focuses on ensuring adequate calories and protein, reducing processed food intake, managing blood sugar (particularly in patients with diabetes or pre-diabetes), and ensuring hydration. For patients with diabetes, even small improvements in blood glucose control before surgery significantly reduce wound complication risk.
I also advise patients to stop smoking well before surgery. Smoking impairs wound healing, increases infection risk, and reduces bone healing — all of which are particularly relevant for joint replacement. Ideally, smoking cessation should occur at least six weeks before the planned procedure.
Nutrition in Recovery
The nutritional demands of recovery are higher than normal. Your body requires additional protein and calories to repair tissue, regrow muscle, and support the immune response. Appetite may be reduced in the first days after surgery, but it is important to maintain adequate nutrition — particularly protein — from the time you begin eating again.
Constipation is a common and uncomfortable side effect of opioid pain medication, which is often used in the first days after surgery. Adequate hydration and a fibre-rich diet (fruits, vegetables, whole grains) help manage this. Staying well-hydrated also reduces the risk of blood clots and supports kidney function.
In the medium term — the first 6–12 weeks of recovery — continued attention to protein and anti-inflammatory nutrition (rich in omega-3 fatty acids, colourful vegetables, and low in ultra-processed food) supports muscle recovery and may reduce post-operative swelling.
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