How to lose weight without losing muscle

How to lose weight without losing muscle

If you were to imagine losing two to three kilograms of body weight from one moment to the next - would this affect your endurance or running efficiency? Of course, it depends a little on what the lost body mass consists of: The loss of water and muscles is more likely to have a negative effect on your performance and your immune system.

However, getting rid of inactive body mass like fat can increase your performance. Up to a running speed of six meters per second, the net energy consumption increases linearly with the speed.

For comparison: the speed of a world-class marathon at 2:05:00 hours is around 5.6 meters per second. In addition to this linear increase, we need to consider body mass. Your workload while running increases in proportion to your body weight.

This means that the heavier you are, the more energy you use to run. In practice, an athlete who weighs 90 kilograms and runs at twelve kilometers per hour has an energy expenditure of around 1,074 kilocalories per hour.

However, if an athlete weighs only 70 kilograms at the same running speed, energy consumption drops to 835 kilocalories per hour. Depending on whether there is a lack of active muscle mass or simply passive body mass, weight reduction can have a direct impact on running performance.

A reduced energy consumption with the same muscular performance is an important performance reserve for you and your training goals. 

2.5 kilos less, 5 minutes faster

If you can manage to reduce your body fat percentage by about 2.5 kilograms, you could improve your running performance while maintaining the same level of training.

With a body weight of 72.5 kilograms and a marathon time of 3:30 hours, the body weight reduction of 2.5 kilograms alone would enable a target time of around five minutes faster. However, you must not think that you are simply reducing your body weight in order to be able to run significantly faster times.

Of course, your training also remains a decisive factor for your performance! Your fat burning plays a very important role here - not only in terms of optimizing your body weight, but also in terms of fuel delivery for your muscles.

Optimizing fat burning

If you want to minimize your body weight, you must not reduce your muscle tissue, but optimize your fat burning. The best way to do this is to tailor the composition of your food to your workout. Depending on which content is the focus of your training, you have to adapt the proportions of fats, protein and carbohydrates to the total energy intake. 

During phases in which you are mainly working on your basic endurance and long and easy endurance runs are the focus of your training, you should eat a diet rich in fat and protein and reduce your carbohydrate intake. As you increase your fat intake, your fat metabolic capacities increase.

Fats are also high-quality energy carriers , so your body should be trained to use fat metabolism in particular. The high protein content, on the other hand, can protect your muscles when you try to reduce your body weight.

For interval training: carbohydrates

Carbohydrates, on the other hand, need to be increased if you include interval training or threshold runs in your training plan. Once anaerobic metabolism starts to play a bigger role in your workouts, you need to provide your body with the appropriate fuel. In this case, that's the carbohydrates. You can easily get supplements with amazon discount coupons

If you have ever done a spiro-ergometry, you surely know the maximum oxygen uptake. This value is based on body weight and describes how many milliliters of oxygen your body can absorb per minute and per kilogram of body weight.

However, the assumption that a reduction in your body weight is directly noticeable in measurable increases in performance is wrong!

The body fat percentage is crucial

If you lose active muscle mass, for example because you limit your energy intake too much, your oxygen uptake also decreases. It is not about simply losing your body weight; you have to reduce your body fat percentage in order to be able to influence your running performance.

Studies have shown that the BMI and the running performance of marathon runners were not related. However, the body fat percentage plays a very important role in running! So if you weigh the same body weight as your fellow traveler but have a lower body fat percentage, you have an advantage.

For runners, reducing body weight is not an easy task. Simply building up a calorie deficit and reducing body mass without considering losses can quickly lead to an increased susceptibility to injury or infection, so that you have to reckon with training failures.

The loss of muscle mass in particular is to be viewed critically, as you may lose performance as a result. On the other hand, even a slight reduction in your body fat percentage is a way of increasing your performance.

In this way, you can develop a performance reserve that enables you to achieve your personal best. For marathon runners in particular, the nutritional information outlined above is another power reserve that can cause your best time to tumble regardless of the adjustment of your body mass.

A training diary helps you lose weight

Your body weight and your mileage are directly related. But this only applies if you take the body fat percentage into account. However, your body mass includes other factors that do not directly limit your performance.

In any case, you must not unilaterally equate reducing your body weight with a possible increase in performance. If you turn the wrong screw, this can negatively affect your performance.

Measuring the subcutaneous fatty tissue with the help of a special caliper should be an interesting tool for observing your performance development. However, you need to be aware of the potential negative effects that can arise from simply relating your performance to your body weight. Ultimately, your training and your possible performance development can be seen as individually as your fingerprint.

General training recommendations are just as wrong as one-sided diet recommendations. You always need to be aware of your body and feel training-induced changes. A training diary helps to identify the adjustments described.


Selena is a blogger and a guest contributor for a well-known brand that includes MESHEBLE & INTHEMARKET. In her leisure time, she plays tennis.