By Michael J. Critelli | MakeUsWell Newsletter, 

Two friends of mine each had very different major surgeries on July 23, 2026, one in Naples FL and one in Bonita Springs, FL. When patients leave these hospitals after surgery, they are likely to have been given highly detailed dietary instructions, as I learned after a surgery in one of those hospitals in 2021.  

After bowel surgery, they may be told to avoid fiber. After gallbladder surgery, they may temporarily limit fatty foods. After oral surgery, they may eat only liquids or soft foods. These restrictions are easy to understand because they relate directly to the body part that was treated.

But there is a less obvious issue that affects recovery from almost every kind of surgery: blood-glucose control.

Most people associate blood sugar with diabetes rather than wound healing. Yet surgery places the body under significant metabolic stress. Stress hormones such as cortisol and adrenaline prompt the liver to release glucose and make the body temporarily more resistant to insulin. Pain, infection, inactivity, intravenous nutrition and some medications, especially corticosteroids, can raise glucose further. This means that even a person without diagnosed diabetes may experience temporary postoperative hyperglycemia.

Elevated glucose can interfere with several processes needed for healing. It can weaken the ability of white blood cells to combat bacteria, impair circulation through small blood vessels, disrupt the orderly inflammatory response and interfere with the cells that produce collagen and close wounds. The practical consequences can include slower healing, weaker wounds and a greater risk of surgical-site infection. These concerns are particularly important after cardiac surgery, joint replacement, vascular procedures, abdominal operations, reconstructive surgery and any procedure involving implanted hardware or tissue whose blood supply is vulnerable.

This does not mean that every surgical patient should follow a sugar-free diet. The medically important goal is controlling blood glucose, not eliminating every food containing sugar or carbohydrate. Healing requires adequate calories, protein, vitamins and minerals. Overly restrictive eating can create malnutrition and undermine recovery. The more sensible approach is usually to limit sugary drinks, desserts and large portions of rapidly absorbed refined carbohydrates while eating adequate protein, vegetables, whole fruits and less-refined carbohydrates.

Hospitals increasingly treat glucose as an important perioperative vital sign. The American Diabetes Association’s 2026 standards recommend a perioperative glucose range of 100 to 180 milligrams per deciliter and advise against excessively strict targets that could cause dangerous hypoglycemia. The CDC’s surgical-site-infection guideline recommends maintaining perioperative glucose below 200 milligrams per deciliter, whether or not the patient has diabetes.

Are patients less conscious of this issue than they are of conventional postoperative dietary restrictions? I would not be surprised if they were less conscious of the significance of this than they were of the other dietary restrictions. I found little research directly comparing patient awareness of glucose control with awareness of restrictions such as low fiber, low fat or soft foods. However, studies have documented gaps in surgical wound-care education, and a 2023 survey reported in the Canadian Journal on Diabetes entitled “Barriers to High-quality Postoperative Glycemic Management by Surgical Teams: A Theory-informed Qualitative Analysis” found important knowledge deficits about perioperative glucose management even among surgeons.  If clinicians do not consistently explain the connection, patients are unlikely to recognize it on their own.

The communication problem may arise because glucose management often occurs invisibly. Hospital staff check glucose, adjust insulin or modify intravenous fluids, while patients perceive these actions as diabetes management rather than wound care. 

Discharge instructions may focus on the incision, medications, lifting restrictions and procedure-specific foods without explaining that metabolic conditions throughout the body influence whether the incision heals successfully. Research describing perioperative diabetes management as reactive rather than proactive reinforces the possibility that the issue is not always communicated or managed as systematically as it should be.

The better message is not simply, “Avoid sugar after surgery.” It is: “Healing depends partly on keeping glucose within a healthy range.” Patients with diabetes or prediabetes should discuss medication changes, monitoring and target levels with their surgical team. Other patients should understand that concentrated sugars, inadequate nutrition and surgical stress can all affect recovery. Glucose control deserves a place beside protein intake, hydration, infection prevention and wound care as a basic principle of optimized surgical healing.