Understanding Body Composition

May 12, 2022

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?

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Understanding 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, that is; 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



See Below


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


Understanding Body Composition

  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 Free Fat Mass and Total Body Water. 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


Understanding Body Composition

  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.

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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.

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