Torn ACL? What Should You Eat?

Hopefully you don’t tear your ACL this ski season or injure any other body part. But if you do, the last thing you are going to think about is what you should eat. But you should…

Nutrition for ACL Injury

Injuries produce stress, both mental and physical. Stress is, in addition to everything else, a hypermetabolic state—which means your body is consuming calories rapidly. The demand for glucose and the amino acids of protein ramps up, inducing the hormonal responses that cause muscle catabolism or breakdown. An initial acute inflammation occurs with every injury, initiating the healing response. Chronic inflammation may set in, continuing the high metabolic demands. If surgery is required, the pre-surgery stress adds to the metabolic demands—and surgery itself leads to increased caloric loads (required for healing). This accelerates muscle atrophy, which begins within hours of injury or immobilization and may continue for months. 

The mental stress involved further ratchets up the caloric demands. Taking all of this into account, it follows that if you don’t optimize your nutrition, you accelerate your demise(1).

Out-of-date advice to fast prior to surgery further leads to nutritional depletion. Ingesting a high-carbohydrate beverage in the hours before surgery should be both safe and effective are reducing catabolic surgical stress(2,3,4). Naturally, many people think that since they are less active in the recovery phase of an injury they should eat less. Yet a negative energy balance (less food but more stress) exacerbates the problems of wound healing and increases the risk of infection(5,6)

Injury-induced stress may increase protein requirements by 80%, just to maintain preinjury body mass(7). Still, the timing of protein consumption may also matter. One large protein meal a day is not as effective in muscle building as ingestion just after exercise and in multiple small amounts during the day.

Increasing protein, in combination with complex carbohydrates—evenly distributed throughout the day—can counterbalance the catabolic state. But not just any protein. Foods high in the amino acid leucine have been shown to increase muscle protein synthesis(8). Animal, whey, and fish protein sources are significantly higher in leucine and essential amino acids than pea, soy, and rice protein. For example, just 25 g of whey protein would be equivalent to 38 grams of pea protein or 40 grams of soy protein.

And it’s best not to drink too much during recovery. Alcohol, while a treat to wash away the sorrows of the injury, impairs muscle protein synthesis and wound healing(9,10).

Complex carbohydrates reduce muscle catabolism. Whole grains, fruits, and vegetables provide the ingredients necessary to support multiple physiological processes necessary in healing. Fat counts, too. 

Monounsaturated fats from avocados, olives, nuts, and seeds provide a steady source of energy during exercise and can help promote muscle recovery. 

Polyunsaturated fats specifically omega-3 fatty acids from fatty fish, chia seeds, and walnuts help reduce muscle soreness and enhance endurance. 

Supplements, vitamins, and probiotics also play critical roles in stimulating collagen synthesis, wound healing, and bone formation: all part of the healing process. But it doesn’t matter what you eat if you don’t absorb it properly. The entire processes of both gut metabolism and the gut microbiome are influenced by any change in diet, the acidity produced in the stomach from stress, and a host of other insults. But the biggest negative may be the nuclear bombs called antibiotics that, when given at surgery, wipe out billions of essential microflorae living throughout your intestinal tract. Repopulating the gut biome with a balanced diet is another critical step in the production of a healing environment.

So, the next time you suffer an injury, use it as an excuse to both optimize your diet and fuel your recovery with powerful nutritional stimulants for muscle building. Your doctor (and body) will thank you.


  1. Smith-Ryan AE, Hirsch KR, Saylor HE, Gould LM, Blue MN. Nutritional considerations and strategies to facilitate injury recovery and rehabilitation. Journal of Athletic Training. 2020;55(9):918-930. doi:10.4085/1062-6050-550-19

  2. Gianotti L, Morelli L, Galbiati F, et al. A randomized double-blind trial on perioperative administration of probiotics on colorectal cancer patients. World J Gastroenterol. 2010;16(2):167-175. doi: 10.3748/wjg.v16.i2.167

  3. Schricker T, Lattermann R. Strategies to attenuate the catabolic response to surgery and improve perioperative outcomes. Can J Anaesth. 2007;54(6):414-419. doi: 10.1007/BF03022026

  4. Soop M, Nygren J, Thorell A, et al. Preoperative oral carbohydrate treatment attenuates endogenous glucose release 3 days after surgery. Clin Nutr. 2004;23(4):733-741. doi: 10.1016/j.clnu.2003.12.007

  5. Evans DC, Martindale RG, Kiraly LN, Jones CM. Nutrition optimization prior to surgery. Nutr Clin Pract. 2014;29(1):10-21. doi: 10.1177/0884533613517006

  6. Demling RH. Nutrition, anabolism, and the wound healing process: an overview. Eplasty. 2009;9:e9.

  7. Jager R, Kerksick CM, Campbell BI, et al. International Society of Sports and Nutrition position stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20. doi: 10.1186/s12970-017-0177-8

  8. Nicastro H, Artioli GG, Costa Ados S, et al. An overview of the therapeutic effects of leucine supplementation on skeletal muscle under atrophic conditions. Amino Acids. 2011;40(2):287-300.

  9. Parr EB, Camera DM, Areta JL, et al. Alcohol ingestion impairs maximal post-exercise rates of myofibrillar protein synthesis following a single bout of concurrent training. PLos One. 2014;9(2):e88384. doi: 10.1371/journal.prone.0088384

  10. Jung MK, Callaci JJ, Lauing KL, et al. Alcohol exposure and mechanisms of tissue injury and repair. Alcohol Clin Exp Res. 2011;35(3):392-399. doi: 10.1111/j.1530-0277.2010.01356.x

Medically authored by
Kevin R. Stone, MD
Orthopaedic surgeon, clinician, scientist, inventor, and founder of multiple companies. Dr. Stone was trained at Harvard University in internal medicine and orthopaedic surgery and at Stanford University in general surgery.