Body Weight vs. Body Composition

Posted: 11/09/2022

You know what your body weight is, and what it means, but do you know what your body composition is and what that means? The two terms tend to be used interchangeably, especially when referring to weight loss and weight gain. However, they are very different and because you are improving your body weight doesn’t necessarily mean that you are improving your body composition. This blog dives into the differences of each and ways to improve your body weight and body composition. 

Body Weight 

Most of us know and understand that body weight is a measure of your entire body mass. Many people have an at-home scale so that they can keep track of their weight from week to week, or even day-to-day. However, there are some people who don’t know weight until going to their yearly doctor’s appointment. Weight is one of the of the most important measures of health and should be taken at least yearly, but preferably more often. Weight fluctuations, especially sudden, can be an indication of disease or changes in body function that needs to be evaluated. BMI, or body mass index, is another measure that takes weight and height into consideration and is usually discussed at your yearly doctor’s checkup. Normal BMI is 20.0-24.9, overweight is 25.0-29.9, and obese is over 30. This is usually a good indication of your weight for height and can tell more about your body than just your weight. 

Body Composition 

Body composition is an indicator of the percentage of fat, muscle, and bone in the body. It is harder to get a value than body weight because it usually involves a special scale, a machine called the bod pod, hydrostatic weighing, or a DXA scanner. Although these methods are very different in how they are performed, the outcome is the same. Each method will determine your percentage of fat, percentage of muscle, and percentage of bone density, all of which equal 100% when combined. The difference between weight and body composition is that weight can’t tell you about your fat percentage versus muscle percentage. For example, two people with the same weight can have very different body compositions. 

When losing weight, it is recommended to lose fat instead of muscle, since muscle is a leaner tissue and improves metabolic rate and ability to move and perform tasks more efficiently. This is the importance of knowing your body composition in addition to your weight, especially when going through a weight loss program. 

Ways to Improve Body Weight and Body Composition 

Losing weight does not always lead to an improved body composition. This is where diet and exercise play a huge part in determining improved body composition with losing weight. By implementing the following things into your routine and lifestyle, you can help improve not only your weight, but also your body composition (fat versus muscle stores). 

  • Resistance training – resistance training is the only way to increase your lean muscle mass. With an increased lean muscle mass, your body will increase its metabolic rate to burn more fat stores, therefore improving your body composition while losing weight. Examples of resistance training include weights, barbells, medicine balls, HIIT (high intensity interval training), plyometrics, and even some body weight exercises such as squats, pushups, leg raises and planks. 
  • Adequate protein – ensuring you are fueling your body the right way usually starts with caloric intake and making sure that you aren’t consuming more than you need to, but second to this is looking at protein intake. With increasing resistance training to improve body composition, your muscle need fuel to grow and lengthen. The muscles fuel is protein. 
  • Reduced saturated fats – saturated fats are the “unhealthy” fats. They are solid at room temperature and are one of the leading causes of plaque buildup in the arteries, heart disease, and heart attacks. In addition, saturated fats add to the fat stores in the body if eaten in excess. By making sure that your saturated fat intake is less than % of your total calorie intake, you can improve your body composition and fat % within the body. 

Bottom line 

Body weight and body composition are very different, but they work together to give you a better idea of your overall body health. Normal weight is shown in terms of BMI and is considered 20.0-24.9. Normal body fat percentage defined by the American Council on Exercise is defined aa 21-24% with an acceptable range of 25-31%. The closer to 20% body fat you have, the more likely you are to be healthy and have a low risk 

It has been shown that a normal body weight and normal body fat percentage is associated with a lower risk for metabolic and heart diseases such as diabetes, heart disease, stroke, heart attack, and metabolic syndrome. By incorporating some of the above lifestyle changes to diet and exercise, you can improve your weight and your body composition to live a healthier life. 


  1. Borga M, West J, Bell JD, Harvey NC, Romu T, Heymsfield SB, Dahlqvist Leinhard O. Advanced body composition assessment: from body mass index to body composition profiling. J Investig Med. 2018 Jun;66(5):1-9. doi: 10.1136/jim-2018-000722. Epub 2018 Mar 25. PMID: 29581385; PMCID: PMC5992366.
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