More performance, fewer numbers: Why the scale doesn't tell the whole story

In many endurance sports, body weight is almost automatically part of the performance discussion. Especially in running, cycling, or triathlon, the false assumption often still prevails: lighter always means faster. In reality, body weight is a performance-determining factor in these sports – just as it is in ski jumping, high jump, or long jump.

But this is precisely where a problem often arises: Many athletes focus so intensely on the number on the scale that they completely neglect other crucial factors. Calorie consumption is meticulously tracked, meals are skipped, and every weight fluctuation impacts mood and eating behavior. The sport suddenly stops being about performance, health, or the joy of movement – and becomes solely about achieving the lowest possible body weight.

What's often forgotten is that lower weight alone doesn't automatically make anyone faster or fitter. On the contrary. Those who think too extremely often lose precisely the things that determine long-term performance – energy, recovery, sleep quality, and training consistency.

Calories are not equal to performance

Many people today also decide to use a nutrition app for weight management. Calories are precisely counted to avoid overeating. However, we should remember that the calorie values of our foods are only theoretical averages. They are based on calculations and not on how much energy our body actually absorbs and utilizes individually. Because our body doesn't function like a machine. How many calories are actually used depends, among other things, on:

• how a food has been processed,
• how well we digest it,
• how our metabolism works,
• and also how the meal was prepared (cooking process).

This also means: The number on the packaging is never the whole truth. Nor is the number on the scale a complete indicator of fitness or health.

Performance needs energy – not just restriction

Many athletes underestimate the importance of adequate energy intake for performance improvements. Those who consistently eat too little may lose weight in the short term, but training quality often suffers simultaneously. Intense sessions feel harder, legs get tired, and recovery takes longer.

Aggressive diets or extreme calorie restriction are particularly problematic. The body switches into energy-saving mode, hormones become imbalanced, and performance declines. Therefore, a moderate calorie deficit is significantly more sensible than crash diets. Small adjustments over a longer period usually yield better and more sustainable results.

Sleep: the underestimated performance factor

While training and nutrition are often optimized down to the smallest detail, a crucial factor frequently remains overlooked: sleep. Adequate sleep not only influences recovery but also hunger, metabolism, and body fat. Those who consistently get too little sleep often experience more cravings, recover less effectively, and process training stimuli less efficiently. Many athletes try to control every little thing through nutrition but simultaneously neglect their sleep – even though sleep itself has an enormous impact on performance and body composition.

Carbohydrates are not the enemy

Especially in endurance sports, carbohydrates often have a bad reputation. Many drastically reduce them to lose weight faster. However, carbohydrates are the most important energy source for intense efforts. The key is not to avoid carbohydrates completely, but to use them strategically – especially around intense training sessions. Those who provide their body with energy at the right time can train harder, recover better, and achieve more progress in the long term.

Health & Performance over a False Ideal Weight

Ultimately, the goal should not be to be as light as possible, but as high-performing as possible. An extremely low body weight offers little benefit if energy, motivation, and health suffer as a result. The most successful athletes are rarely those with the lowest weight – but rather those who train healthily long-term, remain consistent, and give their bodies what they need. A sustainable and performance-oriented body weight with an appropriate body composition is not achieved through extremes, but through intelligent habits:

• sufficient sleep,
• good and regular training,
• periodised and well planned nutrition,
• sufficient energy intake,
• and patience.

That's exactly where the focus should be – not just on the number on the scale.

Further reading:

Manore MM. (2015). Weight Management for Athletes and Active Individuals: A Brief Review. Sports medicine (Auckland, N.Z.), 45 Suppl 1(Suppl 1), S83–S92. https://doi.org/10.1007/s40279-015-0401-0.

Manore MM (2018). Weight Management for Athletes and Active Individuals. Sports Science Exchange, Gatorade. https://www.gssiweb.org/sports-science-exchange/article/weight-management-for-athletes-and-active-individuals/1000.