Eat Right Before Surgery: What the JACS Review Proves
If you have an elective procedure coming up, the weeks before your surgery date matter more than most people realize. A landmark review published in the Journal of the American College of Surgeons (JACS) has confirmed what researchers suspected for years: what you eat and how you move in the lead-up to surgery directly shapes how well you recover afterward.
The findings aren't subtle. Patients who followed structured prehabilitation programs, combining targeted nutrition support with supervised exercise, experienced significantly fewer post-surgical complications and spent less time in the hospital than those who received standard pre-operative care. Here's what the science actually shows, and what you can do about it starting today.
What the JACS Review Actually Found
This wasn't a single small study. The JACS review pooled data from multiple clinical trials, which makes its signal considerably stronger than any individual piece of research. When you aggregate results across diverse patient populations and surgical types, consistent patterns become harder to dismiss as noise.
The central finding was clear: structured prehabilitation, defined as a combination of nutritional optimization and physical exercise implemented 4 to 6 weeks before surgery, significantly reduced the rate of post-operative complications. These ranged from infections and wound healing issues to respiratory complications and hospital readmissions.
The researchers did note study heterogeneity as a meaningful limitation. The trials included in the review varied in their protocols, patient demographics, and surgical contexts. That variation means you shouldn't treat every number as a universal guarantee. But the directional consistency across studies is hard to ignore.
Protein: The Nutrient That Changes the Outcome
Of all the nutritional variables examined, protein intake stood out as a primary driver of better outcomes. Patients who hit adequate protein targets in the weeks before surgery showed measurably faster tissue repair markers post-operatively. That's not a minor detail. It reflects a fundamental biological reality: your body needs amino acids to rebuild tissue, regulate inflammation, and support immune function after the physical trauma of surgery.
The practical target identified in the evidence is 1.2 to 1.5 grams of protein per kilogram of bodyweight per day. For a 75 kg (165 lb) person, that translates to roughly 90 to 112 grams of protein daily. For many people eating a typical Western diet, that's noticeably higher than their current intake.
High-quality protein sources to prioritize include eggs, Greek yogurt, cottage cheese, chicken, fish, legumes, and tofu. The research doesn't mandate a specific dietary pattern, but it does strongly suggest that consistently hitting your daily protein floor is non-negotiable in the weeks before a procedure.
For readers interested in how personalized nutrition science is evolving beyond population averages, Epigenetics and Supplements: How Personal Can Nutrition Get? offers a useful layer of context on why individual responses to diet can vary.
Ultra-Processed Foods: What to Cut and Why
The flip side of optimizing protein is reducing what actively works against your surgical readiness. The prehabilitation protocols reviewed in JACS consistently included reducing ultra-processed food intake as a key component. That means packaged snacks, fast food, sugary drinks, refined breakfast cereals, and processed deli meats.
Ultra-processed foods tend to crowd out nutrient-dense options while contributing to systemic inflammation. Elevated pre-operative inflammation is associated with slower healing, higher infection risk, and longer recovery times. This isn't about crash dieting before surgery. It's about shifting the quality of your food environment over several weeks so your body enters the operating room in a better metabolic state.
A practical approach: don't try to overhaul everything overnight. Start by replacing one or two regular ultra-processed staples with whole-food alternatives each week. Add a protein source to breakfast. Swap a midday snack for a handful of nuts or some yogurt. Small, consistent adjustments over 4 to 6 weeks produce real physiological change.
The Exercise Component: Building Resilience Before the Procedure
Nutrition alone isn't the complete picture. The JACS review specifically assessed prehabilitation as a combined intervention, and the exercise component carries meaningful independent weight. Physical conditioning before surgery improves cardiovascular reserve, muscle mass, and respiratory function, all of which support recovery after the physiological stress of a procedure.
The exercise protocols varied across the reviewed trials, but moderate aerobic activity and resistance training consistently appeared in the most effective programs. You don't need a specialized gym membership or expensive equipment to meet this bar. Brisk walking, bodyweight resistance work, cycling, or swimming several times per week during the prehabilitation window is enough to make a difference for most patients.
If you're looking to add resistance training to your pre-surgical routine and want exercises that are both accessible and evidence-backed, the research on mixing up your workouts and longevity outcomes is worth reading before you build your weekly plan.
It's also worth noting that the benefits of exercise aren't purely muscular. Regular physical activity in the weeks before surgery supports sleep quality, reduces anxiety, and helps regulate stress hormones. Given that pre-surgical anxiety is extremely common, anything that genuinely moderates your stress response has real clinical value. The 4 A's of Stress Management offers a practical framework for managing that pre-procedure mental load.
How Much Shorter Were Hospital Stays?
The JACS review found that hospital stays were measurably shorter in patients who completed structured prehabilitation programs compared to standard care controls. The magnitude varied by study and surgical type, but the pattern was consistent enough across the pooled data to represent a meaningful clinical signal.
Shorter hospital stays translate to more than personal comfort. They reduce exposure to hospital-acquired infections, lower healthcare costs, and allow patients to return to normal functioning sooner. From a public health standpoint, this is why surgical teams at major centers are increasingly implementing prehabilitation as standard protocol rather than optional guidance.
The implication for you: if your surgery is elective and you have a 4 to 6 week window before the procedure, that time is genuinely valuable. It's not a waiting period. It's a preparation phase with measurable consequences for what happens after you wake up from anesthesia.
Your 4-to-6-Week Prehabilitation Protocol
Based on the evidence reviewed in JACS, here's a practical framework you can apply without a clinical team:
- Hit your protein target daily. Calculate your target using 1.2 to 1.5 grams per kilogram of bodyweight. Track your intake for the first week using a free app to understand your baseline before adjusting.
- Reduce ultra-processed foods progressively. Don't aim for perfection on day one. Identify your two or three most frequent ultra-processed foods and find whole-food substitutes over the first two weeks.
- Exercise at least 3 to 4 times per week. Combine moderate cardio with resistance work. You don't need high-intensity sessions. Consistency across the full 4 to 6 week window matters more than peak effort on any single day.
- Prioritize sleep. Tissue repair, immune function, and metabolic regulation all depend on sleep quality. If you're regularly falling short, addressing this is part of prehabilitation too. Understanding how much sleep you actually need is a practical first step.
- Reduce alcohol intake. The evidence on alcohol and surgical outcomes is consistent: even moderate regular intake in the pre-operative period is associated with slower healing and higher complication rates.
- Communicate with your surgical team. If you have specific medical considerations, run any significant dietary changes by your surgeon or a registered dietitian. The general principles apply broadly, but individual circumstances vary.
Why This Review Matters Beyond Surgery
There's a broader principle embedded in this research that extends well past surgical preparation. The JACS findings are essentially confirming that your body's baseline metabolic state, shaped by what you eat and how you move, determines how well it responds to physiological stress. Surgery is an acute stressor, but that logic applies to illness, injury, and aging too.
For anyone tracking the evolving evidence on nutrition and muscle support, Plant-Based Muscle Support: Which Ingredients Actually Have Evidence covers some of the same underlying mechanisms around tissue repair and recovery from a different angle.
The JACS review is a strong piece of evidence, but it's also part of a much larger body of research pointing in the same direction: the choices you make in the weeks before a significant physical challenge shape what happens after it. That's a principle worth building habits around, whether surgery is on your horizon or not.