A Key to Prehabilitation for Surgical Recovery and Cancer Treatment Success

Waist circumference offers more than just a measurement of body size — it provides essential insight into your metabolic health, especially when considered alongside BMI. Many individuals would love a real-time holistic metric of metabolic health. Checking fasting and/or post-meal (“post postprandial”) blood sugar levels is helpful, but tiresome and… a little painful at times. Continuous glucose monitors are extremely cool pieces of technology, but they may be overkill for some and trigger unnecessary food anxiety.

By focusing on waist circumference, you gain a clearer picture of how body composition influences health outcomes, particularly for those with athletic builds or specific body types, such as android (apple) or gynoid (pear) shapes. Understanding the difference between visceral and subcutaneous fat and their impacts on metabolic health can give you an edge when trying to quickly improve inflammation, prediabetes/diabetes, and general wellness — either for longterm health or in the short term when preparing for major medical procedures.

Why Waist Circumference Matters Alongside BMI

Body Mass Index (BMI) has long been used as a general indicator of health, but it has its limitations. BMI doesn't account for how weight is distributed, nor does it distinguish between muscle mass and fat. Waist circumference helps contextualize BMI, offering a clearer view of health risks based on body composition.

Three Body Types and the Role of Waist Circumference

1. Athletic Build: A person with an athletic physique may have a higher BMI due to muscle mass, which can misclassify them as overweight. By including waist circumference, you can differentiate between muscle and fat, giving a better understanding of health risks. A 6’ tall, 200lb individual with a 30-inch waist likely has a more optimal metabolic picture than:
   • A 6’ tall, 160lb individual with a 30-inch waist. This drop in weight for the same waist circumference implies less muscle mass, which acts as an important storage area for blood sugar, has anti-inflammatory benefits, and likely increases resting metabolic rate.
   • A 6’ tall, 200lb individual with a 36-inch waist. This increase in waist circumference at the same weight implies less total body muscle mass to offset the increased fat mass around the middle.
2. Android Shape (Apple-shaped): Those with more fat around the abdomen (“android” phenotype) are at higher risk of conditions like heart disease and diabetes, even if their BMI is in the normal range. Waist circumference can identify these risks more clearly, as fat stored viscerally is pro-inflammatory and, in some ways, self-propagates metabolic disease. More on that later.‍
3. Gynoid Shape (Pear-shaped): People who carry more fat around the hips and thighs (gynoid phenotype) typically have a lower risk of metabolic issues compared to those with abdominal fat, all else held equal. By measuring waist circumference, clinicians can differentiate between these two phenotypes and offer more personalized advice.

By measuring waist circumference alongside BMI, we have a low tech, noninvasive way to better predict health risks, especially when preparing for major interventions like surgery or cancer treatment. This combination of metrics also highlights the danger of visceral fat, which is fat stored around organs in the abdomen.

What is Visceral Fat and Why Is It Harmful?

Visceral fat is the fat stored deep within your abdomen, surrounding organs like the liver, pancreas, and intestines. This fat is particularly dangerous because it actively produces inflammatory substances, hormones, and chemicals that disrupt metabolic processes. Visceral fat is metabolically active and releases these harmful molecules in to the bloodstream, significantly increasing the risk of heart disease, insulin resistance, and type 2 diabetes.

In contrast, subcutaneous fat (the fat just beneath the skin) is generally less harmful but is stubbornly harder to mobilize. Fortunately, visceral fat is typically easier to lose when addressing metabolic health. Reducing visceral fat not only improves physical appearance but also leads to substantial internal health benefits, particularly in the context of surgery and cancer treatment.

As an aside, this is one reason why men seem to have an easier time losing weight. The anecdote we use is a standard male patient who saunters into the waiting room after having dropped 20 pounds in a month just from switching to light beer. In this scenario, the explanation would be that, although it is more metabolically dangerous, visceral fat is preferentially burned in a period of reduced caloric intake.

Vignette 1: Preparing for Surgery — Why Visceral Fat Matters

Consider a patient preparing for major surgery, such as knee replacement. The patient’s waist circumference indicates they carry significant visceral fat, putting the mat higher risk for complications. By incorporating prehabilitation — a regimen of diet and exercise aimed at reducing visceral fat — the patient can improve their metabolic health. Instead of having to get serial cholesterol panels, blood sugar/hemoglobin A1C% checks, etc., this patient can roughly track their health progress by comparing changes in waist circumference to their changes in weight.

Visceral fat is more easily shed than subcutaneous fat, especially when combined with physical activity and a well-balanced diet. Losing just a few pounds of visceral fat can lead to significant health improvements, which in turn can reduce risks during surgery.

Health Benefits of Reducing Visceral Fat Before Surgery

     1.  Lowered inflammation: Reducing visceral fat decreases systemic inflammation, reducing the likelihood of surgical complications.

     2.  Improved insulin sensitivity: Less visceral fat improves how easily the body can control blood sugar fluctuations, and elevated blood sugar is a major risk factor for surgical site infections and other complications.

     3.  Enhanced cardiovascular health: A decrease in visceral fat lowers blood pressure and cholesterol, both of which reduce the risk of anesthesia-related complications in the short term.

The Power of Prehabilitation Before Surgery

Reducing waist circumference and visceral fat can have a direct impact on surgical outcomes. Prehabilitation — the process of optimizing the body before surgery — improves recovery and minimizes risks.

     1.  Shorter hospital stays: Improved metabolic health often leads to faster recovery, meaning patients can leave the hospital sooner. This is one of the more reproducible benefits of prehabilitation in available research.

     2.  Reduced risk of infections: Lower visceral fat levels correspond with improved immune function and blood sugar control, both of which reduce the likelihood of surgical site infections.

     3.  Quicker recovery times: Patients in better metabolic health tend to recover more quickly, with less post-operative pain and complications.

Vignette 2: Preparing for Cancer Treatment — Why Body Composition Matters

Now imagine a patient undergoing treatment for breast cancer. This patient’sBMI alone may not tell the whole story about their health risks but measuring waist circumference reveals they have a higher amount of visceral fat. The oncologist explains that reducing this abdominal fat through weight management and body recomposition can not only improve their body’s response to chemotherapy but may also reduce the risk of cancer recurrence.

Visceral fat fuels the production of hormones like estrogen and growth pathways from high insulin levels, which can promote the growth of certain cancers. Reducing this fat before and during treatment helps stack the deck in favor of the most positive potential outcome.

Benefits of Body Recomposition Before/During Cancer Treatment

1. Lower risk of cancer recurrence: Reducing visceral fat decreases the production of harmful hormones and inflammatory markers that can promote cancer growth.
2. Improved response to therapy: Patients who lose visceral fat and maintain muscle mass often tolerate treatments like chemotherapy and radiation better, leading to improved outcomes in some cases.
3. Enhanced quality of life: Achieving a healthier body composition through reducing belly fat and supporting muscle mass can help reduce fatigue and weakness during treatment, improving overall well-being.

Three Key Points for Using Waist Circumference to Improve Health Before Surgery and Cancer Treatment

     1. Waist circumference provides crucial context for BMI: When used in conjunction with BMI, waist circumference helps highlight health risks more accurately, especially in individuals with specific fat distribution patterns.

• Waist circumference identifies high-risk android (apple-shaped) body types, which carry more visceral fat.
• Waist circumference better contextualizes BMI for those with high muscle mass or gynoid (pear-shaped) fat distribution, offering a more tailored approach to health assessments.

     2. Burning belly fat reduces risks before surgery: By reducing visceral fat, patients can improve their metabolic health, resulting in better surgical outcomes

• Pre-procedural optimization (prehabilitation) shortens hospital stays, allowing patients to recover faster and return home sooner.
• Improving metabolic health before surgery lowers the risk of infections and speeds up post-operative recovery.

     3. Body recomposition can improve cancer treatment and long-term outcomes: Reducing visceral fat and maintaining muscle mass improves cancer therapy          outcomes and lowers the risk of recurrence.

• Losing visceral fat reduces the hormonal and inflammatory factors that promote cancer growth.
• Maintaining a healthy body composition supports better tolerance of chemotherapy and radiation. Research suggests that both significant weight loss and weight (fat) gain can worsen outcomes.

Conclusion

By using waist circumference alongside BMI, we gain a deeper understanding of a person’s metabolic health. This combination allows for more accurate assessments, especially when preparing for surgery or cancer treatment. Reducing visceral fat — the fat most associated with health risks — can lead to better surgical outcomes, reduced cancer recurrence, and improved responses to treatment. Whether preparing for surgery, cancer therapy, or just trying to most efficiently improve metabolic health, focusing on body composition and waist circumference can make a significant difference in health and recovery.

Click here for Part 2 where I’ve proposed specific exercises and other strategies to target visceral fat for faster results and better health.

‍

Alexander Watson, MD is a distinguished physician specializing in physical medicine & rehabilitation (PM&R) with a clinical focus on obesity medicine.  He is the lead physician and founder of Admire Medical in Middletown, DE. Dr. Watson earned his medical degree and a master’s degree in business administration from Rutgers, The State University of New Jersey. He completed his residency training at the University of Pittsburgh Medical Center, where he provided prehabilitation counseling for patients prior to solid organ transplant, spine surgery, bariatric surgery, and cancer treatments.  Dr. Watson has published multiple book chapters and articles on back pain, obesity medicine, and the continuum of care during cancer rehabilitation. He is also the author of Healing in Advance, Your Prehabilitation Handbook, a book for patients (publication date 1/7/2025) and co-editor of A Prehabilitation Guide for All Providers, expected to be released Fall/Winter 2024.

For more on these, check out this page.

‍