Understanding Body Composition - She Runs Eats Performs

Episode 97

Published on:

12th May 2022

Understanding Body Composition

Understanding Body Composition

Body composition is an area most runners focus on but maybe for different reasons. 

For some it may be about losing body fat to reach an appropriate weight, for others it may be to lose body fat to alleviate or prevent certain health concerns….and for others still it may be more about optimising lean body mass to support run training and performance in races/competition. 

So, to help you understand the importance of APPROPRIATE body composition depending on your goals we will address the following 3 questions:

  1. What is BODY COMPOSITION and how is it measured?
  2. Why is it important for health and running?
  3. Which foods/nutrition could support appropriate/optimal body composition?



Defining Body Composition as determined by the Oxford Dictionary of Sports Science and Medicine before moving on to highlight different approaches to measuring Body Composition  


Outlining factors to consider when deciding which method of measuring Body Composition to use. For example; cost and accessibility then moving on to discuss the most popular method i.e. Body Mass Index (BMI)


Moving on to discuss the advantages and drawbacks of two other popular methods of measuring Body Composition. They are: Skinfold Assessment and Bio-electrical Impedance Analysis (BIA)


Delving into the WHY of appropriate body composition for general health and running performance with a focus on the importance of adequate body fat levels for energy production and hormonal function amongst other roles. But also outlining the detrimental effects of excessive fat mass.   


Body composition is dynamic and everchanging so here we look at factors that may influence the degree of fat mass for any given individual



  1. Weight gain appears to be more significant in women compared to men as they age
  2. Due to human physiology, women have a higher value of fat mass than men, BUT, in general it is thought that more men are overweight and obese besides women
  3. With age women tend to show a gradual increase in Fat Mass with a simultaneous decrease in Free Fat Mass and Total Body Water. There is a theory that in the post menopause phase when the production of oestrogen from the ovaries declines that fat cells manufacture small amounts of oestrogen and this may be a reason women have increased fat mass at this time of life
  4. Men, on the other hand tend to significantly decrease in Fat Mass after 40 years of age with a simultaneous increase in FFM and TBW. This is thought to be due to the fact that in men, the peak of body weight increase with age occurs much earlier followed by a normalisation or decrease in body weight

Note: Fat accumulation in both sexes will proceed with different intensity, depending on their:

  • Nutrition
  • Physical activity undertaken
  • Lifestyle


Nutrition to support appropriate Body Composition: Focusing on Carbohydrate and its influence on circulating insulin levels and the impact of that. 


Nutrition to support appropriate Body Composition: Focusing on Protein and its influence on muscle protein synthesis and lean muscle mass


Nutrition to support appropriate Body Composition: Focusing on the different types of Fat and their influence on body fat mass 



Eating Enough to Run

Blood Sugar Balance for Female Runners

Resistant Weight Loss for Runners


  1. Appropriate Body Composition is important for general health as well as running performance and it will be different for everyone depending on their goals
  2. There are many ways of measuring body composition, some of which are more accurate than others. BUT which approach is used will depend principally on accessibility and budget
  3. Optimal body composition does not mean reducing body fat to as little as possible because SOME body fat is essential for general health and running performance
  4. Optimal body composition is more about getting the balance between lean body mass and fat mass, with a limited amount of visceral fat (the fat around the organs, which is metabolically active)
  5. Remember body composition is dynamic and ever changing and there are lots of factors to be considered when determining an individual’s Body Composition. For example: Lifestyle, Age, Gender, Level of physical activity
  6. Carbohydrate, protein and fat are the principal nutrients influencing body composition therefore WHAT FOODS containing each and HOW MUCH of each is consumed needs to be considered


The suggestions we make during this episode are for guidance and

advice only, and are not a substitute for medical advice or treatment.

If you have any concerns regarding your health, please contact

your healthcare professional for advice as soon as possible.

Aileen Smith and Karen Campbell host RUNNERS HEALTH HUB. A place for like-minded female runners who are looking for simple ways to support running performance, energy, endurance, and general great health.

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Happy Running!

Aileen and Karen




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About the Podcast

She Runs Eats Performs
for mid-life female runners of all abilities
Are you confused about the science around nutrition for runners? Listen in to learn about the WHY, HOW, WHAT, and WHEN of eating to fuel your running performance.

We are here to help you translate sports nutritional science, into easy to apply tips and plans, helping you enjoy peak running performance. We focus on the FEMALE FACTORS every mid-life woman needs to know to be a healthy runner.

About your host

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Aileen Smith

Nutritionists, Educators, Podcasters, Runners and Friends

We have a love of running and a passion for nutrition, delicious food and healthy living. She Runs Eats Performs for female runners of all abilities who are looking for simple ways to improve their running performance and their health with nutrition and lifestyle.
We enjoy sharing our nutritional expertise, reviewing the latest sports science and most of all helping you to take easy action so you can enjoy your running life to the full.
We are here to help you achieve great health and good shape whilst staying injury-free with easy-to-understand sports nutritional concepts and easy-to-implement tips and plans.

Aileen and Karen are BANT and CNHC Registered Nutritional Therapists.