What is Body Composition?

Most people chase a number on the scale, especially when they’re trying to lose weight, but that number barely scratches the surface. The number on the scale can go down without improving your overall health, and it can even stall when your body is actually getting stronger, leaner and healthier. That’s because weight alone can’t tell what your body’s made of. 

Body composition goes deeper, showing how much of your weight comes from fat, muscle, bone and water — the stuff that actually impacts your energy, strength, mobility confidence and how you feel day to day.  

In this post, we’ll dive into what body composition is and why it’s a more useful health metric than weight or body mass index alone.

What Is Body Composition?

Body composition is the breakdown of your body into major components like fat, lean mass and bone. Lean mass includes muscle, but it also includes other important tissues like your organs and body water. 

Unlike Body Mass Index (BMI), which only uses height and weight for its calculation, body composition shows how much of your body is fat versus lean mass, giving a clearer picture of what your weight is actually made up of.

Muscle is denser than fat, bone provides structure and strength, and water supports everything from digestion to temperature regulation. Two people with the same height and weight could have very different body compositions and, as a result, have very different health profiles. 

Related: What is Lean Body Mass and Why Does It Matter?

Why Body Composition Is Important 

Understanding your body composition gives you a clearer picture of how your body’s functioning and changing over time. 

When you have more lean mass, your body tends to use energy more efficiently, which can influence how you feel, how you move and how steady your day feels. Lean mass plays a key role in how your body uses energy. Because muscle is a major component of lean mass, protecting lean mass during weight loss helps support strength, mobility and everyday function — even as fat decreases. 

Related: 98% Lean Mass Retention: What Our Latest Findings Reveal About Quality Weight Loss 

How To Measure Body Composition 

If you’re wondering how to measure body composition, several methods can give you insight — from simple at-home tools to advanced medical techniques.

• Body composition scale: Many smart scales use bioelectrical impedance (BIA), sending a gentle electrical signal through the body to estimate things like body fat, lean mass and water composition. Body composition scales make it easy to track changes over time from home. 

• DEXA scans: A medical imaging tool considered a gold standard for body composition. DEXA distinguishes between fat mass, lean mass (which includes muscle, organs and body water) and bone mineral content, offering one of the most detailed and accurate pictures of body composition. 

• Skinfold measurements: Taken with calipers at specific points on the body to estimate overall body fat percentage. 

• Circumference measurements: Simple tape-measure tracking around areas like the waist, hips or arms to show changes over time that the scale might not reflect. 

Each method offers a different level of detail, but they all give you a more meaningful picture of progress — especially when paired with structured nutrition and healthy daily habits.

Factors That Influence Body Composition

Your body composition is not static; it’s influenced by a combination of factors. 

• Genetics: Your genes play a role in things like your natural body type and how your body tends to store fat or build muscle. It’s one piece of the puzzle — not the whole story. 

• Diet and nutrition: The way you nourish your body has a major influence on changes in fat and muscle. Balanced, structured nutrition — like the approach in our clinically proven 5 & 1 plan — provides the right mix of protein, fiber and nutrients to support lean mass and help you stay consistent day to day.

• Physical activity: Moving your body regularly — especially with a mix of strength training and cardiovascular activity — can help support healthy muscle and overall body composition. 

• Age and hormones: As people age, they tend to lose muscle mass and gain fat. Hormonal changes, such as those during menopause, can also affect body composition. 

• Lifestyle: Stress, sleep and daily routines all play a part. When these are out of balance, it can affect energy, mood and how your body stores and uses fuel throughout the day.

The Good News: Body Composition Can Be Improved 

Improving your body composition isn’t about quick fixes — it’s about building daily habits that support more lean muscle, less excess fat and a stronger, more energized you.  

Below you can find a few small steps that can make a big difference: 

• Follow a structured nutrition plan: A predictable nutrition routine — like our comprehensive metabolic health program — gives your body the right balance of high-quality protein, fiber and nutrients to support lean mass and help you stay steady throughout the day.

• Prioritize protein: Include high-quality protein at each meal to support muscle maintenance. This helps your body feel fueled and makes it easier to stay consistent with other healthy habits. 

• Move with intention: Blend strength training with cardiovascular activity. You don’t need long workouts — even short, regular sessions help support muscle and overall body composition. 

• Stay hydrated: Drinking enough water supports digestion, energy and how your body uses nutrients. It also helps you better recognize true hunger cues. 

• Protect your sleep: Quality sleep plays a major role in how your body recovers, repairs and manages cravings. Aim for a consistent routine that helps you wake up feeling more refreshed. 

• Manage daily stress: Finding simple ways to reset — a walk, deep breathing, a quick pause in your day — can help keep your choices more intentional and your energy more stable. 

• Lean on support: Having a real human coach and a community behind you keeps you accountable, motivated and focused on sustainable habits instead of trying to do everything at once. 

Related: Years of Studying Healthy Weight Loss Shows What Actually Moves the Fat Loss Needle

Learn whether your body composition is moving in the right direction with insights Dr. Holly Lofton, director of the medical weight management program at NYU Langone Health.

How Structured, Science-Backed Nutrition Can Improve Your Body Composition

Body composition isn’t just about weight loss — it’s about what you lose and what you keep. With consistent, balanced nutrition, the body is better supported to reduce fat, including visceral fat, while preserving lean mass — which includes muscle. Retaining lean mass is important because muscle makes up a large portion of it and plays a key role in strength, mobility and everyday function.

That’s the foundation of our 5 & 1 plan. By combining healthy habits, structured, portion-controlled nutrition with a balanced mix of high-quality protein, fiber and essential nutrients, the plan is designed to help reduce excess body fat while preserving lean mass — two key drivers of healthy body composition.

In a clinical study, participants experienced outcomes that matter for metabolic health, including a 14% reduction in visceral fat and 98% retained lean mass* — and with the support of a dedicated coach, they lost 10x more weight and 17x more fat than those who went it alone.^†

Because real progress comes from structure you can stick with — not extremes.

Related: Metabolic Synchronization™: Getting Your Biology Back in Sync 

Common Myths About Body Composition

When it comes to body composition, it’s easy to get caught up in misconceptions that can distract from real, sustainable progress. 

• The scale tells the full story. Weight alone doesn’t show changes in body fat and lean mass — real progress can happen even when the number stays the same. 

• Muscle loss is unavoidable. With structured, protein-rich nutrition and supportive habits, the body can preserve lean mass, which includes muscle, even during weight loss. In fact, clinical research on the 5 & 1 Plan showed that participants retained 98% of their lean mass at 16 weeks.** 

• You can spot-reduce fat. Fat loss is influenced by overall metabolic health and individual biology, not targeted exercises. 

• Quick fixes lead to lasting results. Healthy body composition is built through consistency and sustainable habits, not shortcuts.

Beyond the Scale: A Better Path to Progress 

Body composition gives a clearer picture of your health, your metabolism and your progress than weight alone ever could.

When you focus on protecting lean mass, reducing excess fat and building supportive habits, you set yourself up for stronger results. It’s also the heart of OPTAVIA’s approach — quality weight loss supported through structured nutrition, daily habits and personalized coaching.

Ready to see real progress beyond the scale? Learn how structured nutrition and coach support can help support a healthier body composition starting today. 

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*Arterburn LM, et al. Randomized controlled trial assessing two commercial weight loss programs in adults with overweight or obesity. Obes Sci Pract. 2018;5(1):3-14. doi: 10.1002/osp4.312. 

**In a clinical study, 98% of lean mass was retained on the Optimal Weight 5 & 1 Plan® at 16 weeks. In a clinical study, individuals on the Optimal Weight 5 & 1 Plan experienced a 14% reduction in visceral fat at 16 weeks.  

^†Those on the Optimal Weight 5&1 Plan® with support of an OPTAVIA coach successfully lost 10x more weight and 17x more fat than those who tried to lose weight on their own.