Can Running Make You Fat?


The answer is simple - no.

Nothing in isolation will make you fat - whether it be sugar, dietary fat, gluten, running, sitting or anything else.

What makes anyone fat is an excess of energy, which will then be stored for later use. Fat tissue just happens to be this stored form of energy. Energy balance is therefore what determines whether fat stores are depleted or filled. 

But that's simple - and boring - so we had better dig deeper on this topic...


What is Skinny-Fat?

This non-endearing casual term is used to describe an individual with smaller frame and abdominally-dominant fat distribution. These individuals are rarely considered overweight and usually fall into a healthy range on BMI assessments. However, most people do not want this body shape. 

There are two components to this appearance – a lack of upper body muscle mass and slight excess in body fat. The small frame and lack of muscle mass exacerbates the 'skinny-fat' appearance. 

Casual runners can fall into this physique category. If running is their dominant exercise method - particularly long distance running - they may lack upper body muscle mass. If they are also casual exercisers, they may also have an average body fat composition that includes some abdominal fat. This gives the appearance of being skinny while also having a slightly protruding abdomen.

Running does not cause this distribution of body fat, nor does it 'eat muscle away' causing the lack of mass. If this individual had a larger frame and the same amount of body fat, they would not have this appearance. Also, if they were to lose abdominal body fat this would disappear.

Running does not cause skinny-fat, but if running is an individual's only form of exercise, there might be a predisposition towards this appearance. 


The Benefits of Running

Running is a useful form of cardio for the right people. It is cheap (not free – those Nike tights are expensive), accessible and can improve cardiovascular fitness and numerous health markers. 

Many people enjoy the meditative benefits of these and find it very relaxing (I am not one of these people). For the right people, running is an excellent form of exercise to achieving their goals. 


Running for Weight Loss

Despite the above benefits, running is not always the best exercise option for weight loss. Every stride you take puts 7-9 times bodyweight through the ankle, knee and hip joints. If the individual is overweight this will increase the force multiplier going through these joints. Add in a poor running technique to these loads being placed on top of dysfunctional movement pattern, and you have a recipe for injury.

Despite the fact that everyone 'can run', not everyone will be running with good technique. Head to the lake or any other popular running spot this weekend and observe the technique of runners. Look for stride that has the foot landing below the body (not in front), a slight forward lean and a smooth transition between strides. You will see a lot of people running, but few running well. 

The cruel irony is that people who are running to lose weight are often picking the path of most resistance. Additional force is being placed through their joints with each step, fat distribution can alter running mechanics, as can the earlier onset of fatigue. Again, these factors combine to increase the likelihood of injury and decrease the likelihood of adherence. 


Time-Cost: Running v Resistance Training

Energy balance is the determining factor of weight loss or gain and exercise is an important component of this balance.

However, if you burn 600kcal during a running session vs 600kcal during a resistance training session, the outcomes on the body would be different. Both require the same amount of energy expenditure, but the resistance training session can also lead to strength and muscle gains, which won't are unlikely during running.

The duration for 600kcal burnt during resistance training is also likely to be much shorter. For many people, resistance training is better-suited towards their goals and is more time-efficient, particularly in the initial stages of training. Once body composition has been improved towards the individual's goals, then running might be integrated into their program. 


How Do I Program Running?

I have included running programs for client's with goals ranging from general fitness and body recomposition to half-marathons and a 105km ultra endurance run. While running may not be my first choice for cardio,  if the client wants to achieve a running specific goal it will be incorporated as best suits the goals, experience and lifestyle. 

Here are a few of my considerations for programming running:

  • Bodyweight
    • Where do they sit
    • Consider joint loading and risk of injury
  • Experience
    • Are they experienced with running
    • More experience - can likely start at a higher bodyweight (better mechanics)
    • No experience - develop movement patterns and improve body composition
  • Resistance training
    • Will running displace resistance training from their program?
    • Prioritise what is important to the individual (consider enjoyment) and the program
  • Lifestyle 
    • Time consideration - can they do both?
    • Training load - can they handle both?



While running is casually associated with the 'skinny-fat' appearance, it is not the cause and does not need to be avoided. Energy balance and resistance training are more important considerations as their manipulations have significant effects on body composition. Running has a multitude of benefits for health, fitness and enjoyment. However, running is not always best-suited to people trying to lose weight. Correct technique is important to ensuring efficient biomechanics and remaining injury-free.