Protein, carbohydrates, or fat—when it comes to sports nutrition, there’s no one-size-fits-all answer. Athletes' dietary needs should be tailored to their training phase and performance goals. While it’s clear that energy is essential to getting fit, many are unsure where that energy should come from. Are carbs the key to endurance? Is protein the secret to muscle gains? And what role does fat play? The answer depends on your timing and specific fitness objectives.
If you're preparing for a new season or competition, building muscle mass is often a priority, says Dr. Mathias Frey, team physician for the professional footballers at 1. FC Heidenheim. In this phase, your diet should lean more heavily toward protein—about 50% of your total intake. This doesn’t mean eating only eggs; lean meat, fish, legumes, and dairy products are all excellent protein sources. There’s no need to rely on expensive protein bars. Roughly 30% of your calories should come from carbohydrates, such as pasta, rice, and whole grain bread. The remaining portion can consist of fat, which is naturally present in many everyday foods like meat, dairy, and bread.
Once the season is underway—or if your goal is to maintain your current fitness level—your nutritional needs shift. Dr. Frey recommends a balance of 40% protein, 40% carbohydrates, and 20% fat. A good rule of thumb: eat equal amounts of protein-rich foods (like meat, fish, or dairy) and carbohydrate sources (such as whole grains), with a smaller portion of fat.
And one final tip: avoid eating immediately before training. “This stimulates the vagus nerve,” explains Dr. Frey. This nerve helps regulate internal organs, including the heart, lungs, stomach, and intestines. Eating too close to a workout is like “leaving the TV on standby”—your body is running, but not at full power. Ideally, your last meal should be about three hours before training, with a focus on carbohydrates and minimal fat to provide fast, accessible energy without overloading digestion.
