When it comes to assessing your health, the number on the scale—or even your BMI—only tells part of the story. Body composition (the amount of body fat vs. muscle you have) offers a far more accurate picture of your overall health and disease risk. 

Research shows that excess fat, particularly in the abdomen, can increase the likelihood of breast cancer. A meta-analysis in Frontiers in Nutrition of nearly 8 million women found that central obesity—measured by waist circumference or waist-to-hip ratio—was associated with a higher risk of breast cancer in both pre- and postmenopausal women.

Below, we’ll explore the latest research linking body composition to breast cancer risk and practical strategies for optimizing your body composition to support long-term health and cancer prevention.

The Link Between Body Fat and Breast Cancer

Excess body fat is a known risk factor for breast cancer, especially for postmenopausal women. In fact, a meta-analysis in the British Journal of Cancer found that every 5% increase in body fat was linked to about a 15% higher risk of postmenopausal breast cancer. Researchers have identified three main contributing factors.

Inflammation

Fat tissue, particularly around the midsection (referred to as visceral fat), produces chemicals called cytokines that can cause low-level, chronic inflammation. This persistent inflammation can damage healthy cells, creating an environment that promotes the growth and survival of cancer cells, according to a review in the International Journal of Molecular Sciences.

Insulin Resistance

Being overweight or obese can also lead to insulin resistance. When the body becomes resistant to insulin, it compensates by producing more. High insulin levels can stimulate the growth of breast cancer cells and inhibit their natural death, promoting tumor development, according to research in the Journal of Clinical Oncology.

Hormonal Imbalance

Fat tissue can produce estrogen, a hormone that, when elevated, is linked to an increased risk of hormone-receptor-positive breast cancers, according to an article in Scientific Reports. This is particularly true for postmenopausal people, where fat tissue becomes the primary source of estrogen.

Muscle Mass and Breast Cancer Risk

While much attention is given to excess body fat, maintaining healthy muscle mass is equally important in reducing breast cancer risk and improving outcomes for those diagnosed. A study in Discover Oncology found that women with non-metastatic breast cancer and low muscle mass, a condition known as sarcopenia, had a significantly lower survival rate compared to those with normal muscle mass.

Additionally, low muscle mass is linked to higher levels of inflammation, which, in individuals with cancer, can speed up muscle loss and negatively impact health outcomes. On the other hand, having more muscle can help counteract inflammation caused by factors like excess body fat. 

Incorporating regular strength training exercises, such as weightlifting or resistance band workouts, can help build and maintain muscle mass. These exercises not only build physical strength but also support metabolic health and improve overall quality of life.

How Body Composition Can Guide Prevention

Monitoring your body composition is a powerful tool for assessing breast cancer risk and guiding prevention strategies. Unlike weight or BMI, which can be misleading, body composition provides a clear picture of where fat is stored and how much muscle you have, both of which influence your risk.

By establishing a baseline through a body composition scan, which you can do with an InBody body composition scale, you can track changes over time and see how lifestyle choices—like diet, exercise, and strength training—are affecting your fat and muscle levels. Regular assessments allow you to detect unhealthy trends early, adjust your exercise routine, or refine your nutrition plan to maintain a healthier balance of fat and muscle.

You can also track your waist circumference, which is measured at the navel after exhaling. For many women, a goal is less than 35 inches (88 cm).

Tracking these metrics is particularly valuable for postmenopausal people, who are at higher risk for fat-related breast cancer. Maintaining or increasing lean mass (muscle) while reducing fat mass can help lower inflammation, balance hormones, and reduce overall cancer risk.

Strategies for Healthy Body Composition

By combining smart nutrition, consistent exercise, and healthy lifestyle habits, you can optimize your body composition, support your immune system, and take meaningful steps toward reducing your breast cancer risk.

In an analysis of about 180,000 women followed for many years, those who lost weight and kept it off had a lower subsequent risk of breast cancer than women whose weight stayed stable, with larger losses generally linked to larger risk reductions, according to the Journal of the National Cancer Institute.

Eat an Anti-Inflammatory Diet

Focus on eating nutrient-rich, anti-inflammatory foods such as fruits, vegetables, whole grains, and healthy fats like olive oil, nuts, and fatty fish. These foods help reduce chronic inflammation, support hormonal balance, and provide essential nutrients for overall health. 

At the same time, limit alcohol, sugary drinks, and highly processed foods, which can contribute to fat accumulation and inflammation, both linked to higher breast cancer risk.

Strength Train Regularly

A combination of resistance training and aerobic exercise is key to optimizing body composition. Resistance training builds and preserves muscle mass, which can help regulate hormones and counteract inflammation. Aerobic exercise, such as running, brisk walking, or cycling, helps reduce excess fat and improve cardiovascular health.

Aim to do at least two full-body strength-training workouts a week, as well as at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic activity per week, according to the Physical Activity Guidelines for Americans.

Get Adequate Sleep and Manage Stress

Adequate sleep and effective stress management are often overlooked but crucial components of a healthy body composition. Poor sleep and chronic stress can disrupt hormone regulation, increase inflammation, and contribute to fat gain, all of which can raise cancer risk. 

Aim for seven to nine hours of quality sleep per night and incorporate stress-reduction practices like mindfulness, meditation, yoga, or light outdoor activity.

Medically reviewed by Sydney Skinner, PA-C | Updated on September 2025

Thrive Medical Weight Loss, located in Pico Rivera, California, is a medically supervised clinic offering safe, personalized weight-loss solutions. These include GLP-1 weight loss prescriptions like Wegovy and Zepbound, vitamin injections, and supplements. 

To ensure patients lose fat without sacrificing muscle, the clinic uses the InBody body composition scale. Sydney Skinner, PA-C, quickly adopted InBody into her GLP-1 weight loss program after seeing its accuracy in tracking body fat, visceral fat, and muscle.

What Are GLP-1 Medications?

GLP-1 medications are a class of prescription drugs originally developed to treat type 2 diabetes but now widely used for weight management. GLP-1 stands for glucagon-like peptide-1, a natural hormone that helps regulate blood sugar, appetite, and digestion.

These medications mimic the effects of GLP-1 in the body. They slow down how quickly food leaves the stomach, reduce appetite by signaling fullness to the brain, and help control blood sugar levels.

When combined with healthy lifestyle changes, GLP-1 medications can lead to significant weight loss. However, they can also cause unintended muscle loss if progress isn’t carefully monitored.

Why GLP-1 Weight Loss Needs Context

Historically, weight loss has been oversimplified as just a lower number on the bathroom scale. But not all weight loss is created equal. Without context, you may be losing as much muscle as fat.

Losing muscle:

• Reduces metabolic rate, making it harder to maintain weight loss

• Increases frailty, especially in older adults

• Raises the risk of chronic conditions like diabetes, heart disease, and osteoporosis

The rise of GLP-1 receptor agonists (e.g., semaglutide and tirzepatide) has amplified this concern. These medications are highly effective for weight reduction, but their strong appetite-suppressing effects can reduce protein intake. Without proper monitoring, that calorie deficit may accelerate lean muscle loss alongside fat.

The Risks: Muscle Loss on GLP-1s

GLP-1 medications have shown remarkable results, with many patients losing 15–20% of their body weight within a year. For individuals with obesity or metabolic syndrome, these outcomes can be life-changing.

But there’s a hidden danger. Recent research summarized in Nature Reviews Endocrinology reported that up to 40 percent of total weight lost during GLP-1 therapy may come from lean mass in the absence of nutrition and exercise interventions. Losing muscle compromises metabolic health and elevates the risk of weight regain post-medication. That means the number on the scale may look impressive, but the quality of the weight loss could actually undermine long-term health.

Making GLP-1 Weight Loss Safe, Effective, and Sustainable

Thrive Medical Weight Loss addresses the muscle loss issue by pairing GLP-1 therapy with InBody body composition analysis, ensuring fat loss is safe, sustainable, and protective of muscle and metabolism. 

Unlike a standard scale that only shows pounds lost, InBody separates weight into fat, muscle, and water. This allows providers to see what type of weight a patient is losing, making sure progress comes primarily from fat, not muscle.

At Thrive, Sydney Skinner, PA-C, emphasizes that GLP-1 for weight loss programs must include body composition monitoring.

“I can monitor them and make sure they’re not losing too much weight. The right combination of exercise, protein, and monitoring them closely during their weight loss is very key — and the InBody is just essential.”

The Proven Solution: GLP-1 Weight Loss With InBody Monitoring

Thrive uses a five-step approach that pairs the power of GLP‑1 medications with data-driven insights delivered via routine InBody scans and patient education.

Step 1: Baseline Assessment

Every new patient kicks off their program with a complete health evaluation that includes an InBody scan to establish their baseline. Unlike bathroom scales or BMI charts, InBody provides detailed insight into:

• Skeletal Muscle Mass

• Percent Body Fat

• Visceral Fat Level

• Body Water

• Basal Metabolic Rate

• Segmental Lean Analysis

The baseline that InBody delivers gives patients clarity and motivation. Patients learn why preserving muscle matters, why visceral fat is dangerous, and why the goal is fat loss with muscle preservation.

Step 2: GLP‑1 Medication Onboarding

Patients start on GLP-1 for weight loss responsibly - titrated slowly with counseling on hydration, electrolytes, and protein. Patients receive counseling on hydration, electrolytes, and protein intake, which are critical to maintaining muscle while taking appetite-suppressing medication.

Step 3: Nutrition and Exercise Coaching

Because GLP‑1s reduce hunger, patients often under-eat, especially protein. Thrive combats this with structured strategies:

• Protein-first approach: Prioritize 100–120g of protein daily

• Resistance training: 2–3 sessions per week

• Movement goals: Walking, stretching, and low-impact cardio

• Meal planning support

The goal of this multi-tiered approach is to reteach healthier habits with a focus on a protein-rich diet to ensure patients preserve muscle mass during their GLP-1 program.

Step 4: Regular InBody Monitoring

*InBody 570 Result Sheet outputs shown; outputs may differ depending on the model

Patients return every 2–4 weeks for follow-up InBody scans. These check-ins:

• Track muscle vs. fat loss via the Muscle-Fat Analysis metric

• Monitor visceral fat reduction via the Visceral Fat Level output

• Provide real-time feedback on progress shown via the Body Composition History chart and motivate patients to follow through 

When patients see tangible improvements in body fat percentage, visceral fat, and muscle retention, it gives them the confidence and motivation needed to be successful in their weight loss program. 

Step 5: Data-Driven Adjustments

If the InBody scan reveals that a patient’s skeletal muscle mass declines, Thrive acts immediately by:

• Increasing protein targets

• Adding extra resistance workouts

• Adjusting medication titration if weight loss is too rapid

This proactive approach prevents the “skinny fat” outcome that plagues other weight loss programs.

Why Muscle Matters in GLP-1 Programs

Muscle is a metabolically active tissue. Losing muscle reduces basal metabolic rate, the total number of calories you need for your basic essential functions, making weight maintenance more difficult. It also weakens the body, increases the risk of injury, and accelerates age-related frailty.

Without resistance training and adequate protein, GLP‑1 patients risk long-term harm — even as they look thinner.

GLP-1 Weight Loss Success Story: Jane's Transformation

Before getting in touch with Thrive, Jane had tried multiple weight loss programs with varying degrees of disappointing results, but had heard promising things about Thrive’s GLP-1 programming.

Jane's goals were to lose not just weight, but body fat while maintaining her muscle mass. Her initial InBody scan established an essential baseline that revealed where her body composition was at, where she wanted it to be, and the path to get there:

• Weight: 180.1 lbs

• Percent Body Fat: 46.9% 

• Skeletal Muscle: 52.7 lbs

After just nine months of Thrive’s integrated program, Jane was astounded by the tremendous progress made tangible by her routine InBody scan:

• Weight: 150.3 lbs (↓ 30 lbs)

• Percent Body Fat: 37.7% (↓ 9.2%)

• Muscle: 51.6 lbs (preserved)

Jane was able to lose nearly 30 pounds of fat while essentially maintaining the muscle mass she had at the beginning of her program. 

Bottom Line: Sustainable GLP-1 Weight Loss With Muscle Protection

Thrive Medical Weight Loss has redefined what safe and sustainable GLP-1 weight loss should look like. By combining InBody’s advanced body composition technology with personalized nutrition, structured exercise, and ongoing patient education, every pound lost works toward long-term health, not against it. Their evidence-based approach prioritizes muscle preservation, metabolic health, and patient empowerment, ensuring results that go beyond the scale.

In a weight loss industry often dominated by quick fixes and temporary solutions, Thrive stands apart through its integration of science, compassionate care, and accountability. 

FAQs

How does GLP-1 work for weight loss?

GLP-1 mimics the hormone GLP-1, reducing hunger and slowing digestion. By reducing hunger signals to the brain, slowing digestion so food stays in the stomach longer, and improving insulin sensitivity, these drugs make it easier to eat less, feel full sooner, and maintain more stable blood sugar levels. 

What’s the best GLP-1 for weight loss?

Options like Wegovy and Zepbound are commonly prescribed, but the best choice depends on your medical history.

Who Is a Good Fit for GLP-1 Medications?

GLP-1 medications are generally prescribed for adults with obesity (BMI ≥30) or those who are overweight (BMI ≥27) with related health conditions such as type 2 diabetes, high blood pressure, or high cholesterol.  

Are GLP-1s Safe?  

GLP-1 medications are FDA-approved and widely studied, but like any treatment, they can have side effects. The most common include nausea, vomiting, diarrhea, constipation, and stomach discomfort, which often improve over time. Less common but more serious risks can include pancreatitis, gallbladder issues, or thyroid tumors in certain individuals. Regular medical supervision is essential to ensure safe use and to adjust treatment as needed.

How Do You Get the Most Out of Your GLP-1 Treatment?

GLP-1s work best when combined with healthy lifestyle habits. Eating enough protein and incorporating resistance training help protect muscle while losing fat. Staying consistent with follow-up visits and body composition checks, such as with an InBody scan, ensures progress is monitored and treatment is adjusted if muscle loss is detected.  

What Happens When You Stop Taking GLP-1s?

If GLP-1 medication is stopped, appetite typically returns to normal, and some patients regain weight if new lifestyle habits aren’t in place. Without careful planning, lost fat and muscle can come back, making long-term success more difficult.  

While many chase six-pack abs or sculpted arms, real strength comes from building muscles that help you thrive in your everyday life. We call this stealth muscle: the kind that works behind the scenes, improving your daily movement, strength, and longevity.

The way you build stealth muscle? Functional fitness. This type of training focuses on optimizing your body for real-world activities — lifting, bending, squatting, and reaching — so you can move better, feel stronger, and reduce your risk of injury.

What Is Functional Fitness?

Functional fitness is all about preparing your body to handle everyday tasks and movements. Rather than focusing on isolated exercises for aesthetic goals (think: endless biceps curls), functional fitness involves exercises that mimic real-world activities—like lifting groceries (deadlifts), bending to tie your shoes (lunges), or carrying a suitcase (farmer’s carry). 

The 4 Pillars of Functional Fitness

Functional training focuses on four key aspects of fitness, each of which plays a crucial role in creating a well-rounded and effective workout routine.

• Mobility: Mobility refers to the ability to move your joints through their full range of motion without experiencing discomfort.

• Stability: Stability is about maintaining control and balance during movement, particularly in your core and joints.

• Movement involves the coordinated actions of the body’s muscles and joints to perform tasks, such as walking, reaching, or lifting.

• Strength: Functional strength is the ability of a muscle or group of muscles to generate force for tasks that include lifting, pushing, or pulling.

How Does Functional Fitness Differ from Other Forms of Exercise?

While other forms of exercise can also improve fitness, they may not always prioritize functional movement patterns. Here’s how functional fitness compares to popular workout styles.

CrossFit

Functional fitness and CrossFit both involve compound movements, such as squats, deadlifts, and presses that mimic real-life actions, and both aim to improve strength, endurance, and overall fitness. However, CrossFit often focuses on high-intensity, time-based workouts with a competitive edge, pushing individuals to perform at maximum effort for a set duration. 

HIIT

HIIT (high-intensity interval training) and functional fitness both utilize full-body movements and aim to enhance cardiovascular health, strength, and endurance. The key difference is that HIIT is centered around high-intensity bursts of activity with short rest periods, focusing on maximizing calorie burn and improving fitness in a time-efficient way. 

Pilates

Pilates and functional fitness both prioritize core strength, flexibility, and body control to improve posture and movement quality. However, Pilates tends to focus more on low-impact, controlled movements that emphasize balance and alignment. 

Bodybuilding

Bodybuilding and functional fitness both rely on resistance-training exercises like squats, presses, and deadlifts. However, bodybuilding focuses on isolating specific muscle groups to build muscle mass for aesthetic purposes.

What Are the Benefits of Functional Fitness?

By focusing on exercises that mimic real-life movements, functional fitness training provides a wide range of benefits. These include:

1. Improved Mobility and Flexibility

Functional fitness workouts promote joint mobility and flexibility, which are essential for maintaining ease of movement throughout daily life. Whether it’s bending down to tie your shoes or reaching for something on a high shelf, having good mobility helps you move freely and comfortably without stiffness or pain. This can be especially important as we age, helping to maintain independence and reduce the risk of falls.

2. Better Balance and Coordination

By integrating multi-joint movements that involve both the upper and lower body, functional fitness improves balance and agility. Exercises like lunges, squats, and rotational movements train your body to move as a unit, enhancing your ability to stay stable and coordinated during daily tasks, from walking to carrying groceries or playing sports.

3. Enhanced Strength for Everyday Activities

As previously mentioned, functional fitness focuses on building strength in movements that we perform daily, such as lifting, squatting, and reaching. This makes them easier to perform without added risk of strain or fatigue.

4. Reduced Risk of Injury

By improving overall movement patterns and enhancing stability, functional fitness helps reduce the risk of injury. It strengthens the muscles and joints that are responsible for supporting proper posture and alignment, which in turn lowers the likelihood of injury in both active and sedentary environments. It also emphasizes injury prevention through balanced muscle development and proper technique.

5. Improved Posture and Core Strength

A strong core is the foundation of functional fitness, and strengthening the core helps improve posture and reduce back pain. Core exercises in functional fitness train the muscles to support the spine and maintain proper alignment, leading to better posture, less discomfort, and improved athletic performance.

6. Better Mental Health

Fitness doesn't just benefit the body—it also has positive effects on mental health. Regular exercise releases endorphins, which can help reduce stress, anxiety, and depression. Plus, the sense of accomplishment and improved confidence that comes with mastering functional movements can boost mental well-being.

7. Sustainable Fitness

One of the standout benefits of functional fitness is that it’s sustainable. It’s not about extreme lifting or pushing your body to the limit—it's about gradual progress and consistency. Because the focus is on movements that support everyday tasks, functional fitness is something you can continue practicing long-term, without burning out or risking injury.

Is Functional Training Right For You?

Functional training is incredibly versatile and can be adapted to suit people of all ages, fitness levels, and goals. But how do you know if it’s the right fit for you? You might want to consider giving it a try if any of the following apply to you:

• If you’ve ever struggled with tasks like carrying groceries, lifting heavy boxes, or bending down without discomfort

• You’re new to exercise or getting back into it after a break

• You’re recovering from an injury or looking to prevent one

• You're looking for something that will keep you active for the long haul — without the risk of burnout or injury

• If you get bored easily or enjoy a varied workout

• If you’re looking for results beyond aesthetics

What Are the Best Functional Fitness Exercises?

The best functional exercises to incorporate into your routine are those that focus on key movement patterns that mimic real-life actions. These include:

Push

Push exercises help build upper-body strength, specifically in the chest, shoulders, and triceps, and improve pushing movements like opening doors, pushing carts, or pushing yourself up from the floor.

• Push-Ups: Start in a plank position with your hands slightly wider than shoulder-width apart. Lower your body to the floor, keeping your elbows at a 45-degree angle. Push yourself back up to the starting position, focusing on engaging your core and keeping your body in a straight line.

Pull

Pull exercises strengthen the upper body, particularly the back, biceps, and shoulders. These exercises improve posture, enhance pulling movements like opening a heavy drawer, and assist with lifting and carrying tasks.

• Dumbbell Rows: With a dumbbell in each hand, bend at the hips while keeping your back flat. Pull the dumbbells toward your torso while squeezing your shoulder blades together, then lower back down.

Squat

Squats build strength in your legs, hips, and glutes, which are essential for tasks like standing up from a chair, climbing stairs, or lifting objects off the floor.

• Squat: Stand with your feet shoulder-width apart. (Optional: Hold a dumbbell or kettlebell at chest height with both hands.) Push your hips back and bend your knees, lowering your body as if you're sitting in a chair. Keep your chest up and knees behind your toes. Stand back up.

Lunge

Lunges target the legs, glutes, and core, and help improve balance and stability. They mimic movements like walking, climbing stairs, and picking things up off the ground while maintaining balance.

• Forward Lunge: Step one foot forward and lower your hips until both knees are at 90-degree angles. Keep your chest up and core engaged. Push through the heel of your front foot to return to standing. Alternate legs with each repetition.

Hinge

The hip hinge is crucial for building strength in the posterior chain—especially the glutes, hamstrings, and lower back. It’s essential for activities like picking up heavy objects, bending over to tie shoes, or lifting items off the floor.

• Romanian Deadlifts: With a barbell or dumbbells in hand, stand tall with your feet hip-width apart. Hinge at the hips, pushing your glutes back as you lower the weight towards the ground, keeping your knees slightly bent. Engage your glutes and hamstrings to return to standing.

Rotation

Rotational exercises improve the flexibility and strength of your core, helping with movements like twisting to reach for something, rotating your torso during sports, or carrying heavy objects while turning.

• Russian Twists: Sit on the ground with your knees bent and feet flat. Lean back slightly and hold a weight or medicine ball with both hands. Rotate your torso to one side, then to the other, while keeping your core engaged and feet lifted (optional).

How Do You Put Together a Functional Fitness Routine?

Creating a functional fitness routine is about designing workouts that help you improve strength, mobility, and coordination for everyday movements.

1. Start With Your Goals

Before you start planning your routine, think about your fitness goals. Are you an older adult who wants to build balance and stability? Or a runner that needs a routine to help with injury prevention? Your goals will guide the structure of your training program, helping you prioritize certain exercises or movements.

2. Focus on the 5 Key Movement Patterns

To create a balanced functional fitness routine, aim to include exercises that target these five key movement patterns (see above for a detailed explanation):

• Push

• Pull

• Squat

• Hinge

• Rotation

3. Include Mobility and Stability Work

In addition to strength training, mobility and stability are crucial components of a functional fitness routine. You can include mobility work in your warm-up (like dynamic stretches or foam rolling) and stability work in your cool-down or as part of specific exercises (like planks or single-leg stands).

4. Add Variety

Include exercises that train in multiple planes of motion (e.g., forward, backward, side to side) and incorporate different movement types, such as low-impact bodyweight exercises or more dynamic exercises like jumping or sprinting.

5. Structure Your Routine

Here’s a simple framework for structuring your functional fitness routine:

• Warm-Up (5 to 10 minutes): Focus on dynamic stretches or mobility drills (e.g., leg swings, hip rotations, or shoulder circles).

• Main Workout (20 to 40 minutes): Include a combination of strength, stability, and mobility exercises. For example:

  • Start with a full-body compound exercise (e.g., squats or deadlifts).

  • Add in a pushing or pulling exercise (e.g., push-ups or rows).

  • Finish with a rotational movement and core exercise (e.g., Russian twists or planks).

• Cool-Down (5 to 10 minutes): Focus on stretching or foam rolling to help with recovery and improve flexibility.

6. Be Consistent

The key to any successful fitness routine is consistency. Try to aim for at least two to four sessions a week, depending on your goals and fitness level. Consistency, combined with progressive overload (gradually increasing intensity or weight), will lead to noticeable improvements in strength, mobility, and overall functional ability.

7. Listen to Your Body

Finally, always listen to your body. Functional fitness should be challenging but not painful. If you feel discomfort during a movement, it may indicate that you're using improper form or pushing yourself too hard. Make adjustments, take rest days when needed, and ensure you're progressing at a pace that feels right for you.