Key factors for changing body composition through nutrition

Posted on December 17, 2019 by

Manipulating body composition through a reduction in body fat and increase in muscle mass is a common physical goal.

It’s particularly prevalent in weight-specific and power-based sports to reduce non-functional weight while maintaining total body weight to improve power to weight ratio.

Achieving this goal through nutrition strategies isn’t a one size fits all for every athlete and how they approach it requires careful planning around how its approached specific to the individual’s goal and training.

In high performance sport you don’t train just to lost weight and fat.

You train to improve, and you train to push yourself and perform. If this goal supports your training outcomes, how you approach your eating habits and food choices around training and over the whole day will have a bigger impact at reaching this physical goal.

Its not as simple as a blanket reduction in eating, cutting something out, or putting some super fat burning food in.

The key factors to align which play a role in refining body composition and guiding your food choices are as follows:


1. Training

Eating to suit your training demands is the most crucial step in this process and diet should be guided by when your training times are to know when to increase or reduce intake over the day and over the week.

This may mean each day looks different as to what you eat and when as its guided by when you train to maximise the energy used in that session.

Days or afternoons/mornings when you don’t train are opportunities to reduce intake rather than a whole day or whole week reduction leading to getting tired and fatigued when approaching training.


2. Timing meals

Timing meals to suit training demands is important to give the body what it needs to recover from training and stimulate muscle turn over and have fuel available to do this.

In addition, timing meals to ensure there is energy available to fuel the session ahead of you so you have fuel to burn.

Often people think that to burn fat they need to be fasted or reduce intake to very low but this can mean you don’t train as hard or burn as much total energy in that session which can be counteractive to the goal.


3. Portions

Its important to be eating regularly over the day to facilitate muscle turn over and development, regular meals with a protein source helps to stimulate muscle turn over. Managing portion sizes so there is fuel to do this without an excess that isn’t burnt and stored as fat will vary depending on the size and activity of the athlete.

Another way to approach this may mean manipulating ratios of food groups on the plate to have a little more vegetables and less energy dense options. Energy dense intake should be focused around the key training sessions. Reducing energy density of food while increasing nutrient density is best to focus at times training is low or reduced.


The urgency of the goal and amount of change that has to occur will determine how long this process might take. Habits can be refined to enhance training and physique outcomes for this to occur simultaneously during training blocks. However, if there are significant changes to take place it can be a slower progression and more detailed process as practices are refined.

Alternatively you may need to be more targeted with training and stagger dietary focus through phases of training to focus on building muscle and then focusing on fat reduction.

If weight and fat loss is rushed and done incorrectly it can impact health and performance hugely so speaking with an accredited sports dietitian is essential to help do this right.

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