Understanding Body Frame Size
For generations, the term "big boned" has been a popular phrase used to explain a person's larger-than-average size or weight. While some dismiss it as an excuse, the concept of a larger body frame is medically recognized. A person's bone frame size, or skeletal frame, is determined primarily by genetics and can vary significantly from one person to another. This is often measured by taking the circumference of the wrist, which is a good indicator because it doesn't change with weight fluctuations.
How to measure your body frame
Determining your body frame size can help you understand your natural build. One common method involves measuring your wrist circumference and comparing it to your height. Here is a simple guide:
- Wrap a tape measure around your wrist just below the hand. You can also use a string and then measure the string against a ruler.
- Note the measurement.
- Compare this measurement to a standard chart, like the one provided by the National Institutes of Health (NIH), which classifies frame size as small, medium, or large based on height and wrist circumference. For example, a woman over 5'5" with a wrist circumference over 6.5 inches is typically considered to have a large frame.
While a larger frame contributes some extra weight, it is not a significant amount. A medical professional at Marshfield Clinic noted that a larger bone structure might account for only a few pounds, not 30 or 40 pounds of difference. Therefore, relying on this as the sole reason for being overweight or struggling with weight management is misleading.
The Real Science of Body Composition
Rather than fixating on the size of your bones, a more productive approach to understanding your body is focusing on body composition. This refers to the proportion of fat and non-fat mass (muscle, bone, and water) in your body. Body frame size is just one small component of this larger picture.
Bone vs. muscle and fat
Your body's weight is composed of many elements, and bone is a small fraction. A significant portion is muscle and body fat, which are far more variable and responsive to diet and exercise. Muscle is denser and heavier than fat. An individual who is muscular but has low body fat can be considered “skinny” or lean, even with a larger frame. Conversely, a person with a small frame and high body fat percentage may appear heavier or less toned. It's the fat and muscle that have the most significant impact on your overall appearance and shape.
Genetics and your body type
Genetics play a large role in your overall body type, influencing your metabolism, fat storage patterns, and muscular build. The concept of body types—ectomorph (naturally thin), mesomorph (naturally athletic), and endomorph (naturally rounder)—are broad categories that, while not scientifically strict, illustrate the genetic predispositions for certain body compositions. A person with a larger, more robust ectomorphic frame could theoretically appear lean or skinny, while still being heavier than a small-framed ectomorph of the same height.
Dispelling the 'Big Boned' Myth
The most damaging aspect of the "big boned" myth is its use as an excuse for poor health or unhealthy weight. It can lead to a sense of helplessness, making people believe they are destined to be a certain size regardless of their lifestyle. The truth is that while your bone structure provides a foundation, it doesn't dictate your entire body composition.
Myth vs. Fact table
| Myth | Fact |
|---|---|
| I can't lose weight because I'm just big boned. | While a larger frame adds a few pounds, it doesn't cause significant weight gain. Body fat is the primary determinant of weight and can be managed with diet and exercise. |
| Being big boned means you can never be skinny. | Your bone frame and leanness are not mutually exclusive. A person can have a broad, robust frame and still have a very low body fat percentage, appearing lean and athletic. |
| The number on the scale is all that matters. | Your weight is a combination of muscle, fat, and bone. A person with a large frame and significant muscle mass might weigh more than a small-framed person with more body fat, but be significantly healthier. Focus on body composition, not just weight. |
| All overweight people are big boned. | This is a harmful generalization. Being overweight is primarily caused by excess body fat, which can affect people of any body frame size. |
The Healthy Takeaway
Focusing on health rather than a number on the scale or a societal ideal is key. A person with a larger frame can certainly be skinny, or more accurately, lean and strong. This involves prioritizing a balanced diet and regular exercise to build muscle and maintain a healthy body fat percentage.
Instead of aiming for a weight that might be unrealistic for your natural frame, set health-based goals. This might include improving cardiovascular health, increasing muscle strength, or simply feeling more energetic and confident in your body. The National Institutes of Health (NIH) provides a wealth of information on maintaining a healthy weight and body composition. Learn more about healthy body weight here.
Conclusion: Redefining 'Skinny'
The notion that you cannot be big boned and skinny is a misconception rooted in misunderstanding body composition. Your skeletal structure sets your frame, but it is your lifestyle—your diet and exercise routine—that determines how much muscle and fat you carry. Therefore, it is entirely possible to have a larger frame while being very lean. The key is to shift your focus from the scale to overall health, celebrating a strong, robust body rather than chasing an arbitrary number or an unachievable ideal. Embrace your unique build and work toward feeling your best, regardless of your bone size.
