Im going to try to condense a broad-ranged widely contextual topic into 3 main subheadings for consideration when injured.
Not looking after your nutrition when injured MAY hinder or prolong the process and optimizing it through simple interventions will, no doubt, aid the process through the different stages of injury (inflammation, proliferation, remodeling, rehabilitation, etc depending on the severity).
So here we go,
People can shit their pants and either lower intake FAR too much, or overshoot what they perceive is needed for the rehab process. - Lowering intake too much may prolong the healing/recovery process
Overshooting calories may cause the unwanted gain of potential fat mass contributing to systemic inflammation which we don’t want.
The main determining factor of this will be the severity of the injury (if it results in immobilization, crutches) and as a result, assessing if and how much daily expenditure is lowered by paired with the possible extent of the injury and energy needed for the tissue repair itself.
Caloric needs can increase anywhere from 15-50%! Depending on the severity.
Bigger ore serious injuries WILL require more actual calories as energy for the healing process, BUT, if that injury results in severe immobilization and as a result, much lower movement daily or energy expenditure, that has to be taken into account. - MOST of the time caloric needs lower due to decreased expenditure and lack of protein turnover (As the process uses quite a bit of energy).
If no form of resistance training or activity cannot be performed, you may need to increase your intake some bit.
Muscle protein breakdown may increase due to a shift in net protein turnover itself from tissue repair pair combined with a lack of anabolic stimulus via resistance training.
The amount of protein per serving may increase from potential anabolic resistance, again, from lack of training, one of the most anabolic things we can do. - Protein distribution is also very important, generally speaking, more frequent and equally dispersed servings are superior than less frequent higher servings within your daily intake (25g in 4 meals compared to 50g in 2).
If immobilization results in Lack of daily activity AND the inability to train, there's certainly less requirement for carbohydrates (Possible decreased insulin sensitivity less intracellular signaling we get when training).
The extent of if, and how much to lower carbs by, again depends on how much your activity has decreased and if you are performing little to no activity. - A diverse intake of Fat intake from fish, nuts, oils, seeds, eggs, avocado, etc is probably a good shout due to Omega 3’s role in helping inflammation (more on this below) & Joint Health.
To conclude: Increased protein slightly with attention to the distribution of feedings in a day, if your laid up or cannot train, lowering carbohydrate intake, if that reduction results in massively lowering calories (if you generally have a high carb intake), make up the balance by increasing fat intake a bit with daily calories.
As always, a broad-ranged of nutrient-dense, whole food sources as well as in fruit & veg intake is a good idea due to getting more diversified vitamins and minerals, contributing to fiber intake and digestive health (which can take a hit if laid up or bed-bound) and contribute to helping inflammation & feeling satiated/full if calorie intake is lowered.
There is very little conclusive research into sports supplementation (Creatine, Nitric Oxide Boosters, stimulants etc) to see if they contribute any bit significantly to the process. If you always took creatine, simply keep taking it with no loading or cycling.
One important consideration is the use of anti-inflammatory nutritional interventions either via food (Tumeric/Crumlin, L-Gluthatione etc) or Supplementation (Taking High Dose Omega 3’s or Krill oil) can actually hinder recovery as we need an inflammatory response in the early stages of injury, however if inflammation is prolonged they may be applicable.
There is some potential for EAA’s but no current evidence to support their conclusive use as an aid for recovery.
Avoiding Alcohol is probably be a good idea due to the physiological impacts it has which certainly won’t help recovery.