[Column] Misconceptions about protein intake

Many people believe they must chug a protein shake immediately after a workout to promote faster muscle growth and recovery. But when it comes to protein intake, quantity is what matters most. This has been consistently proven across studies. A 2013 U.S. meta-analysis reviewing 20 studies found that the strongest predictor of strength and muscle growth was total protein intake, not the timing of protein consumption before or after exercise.

A 2024 study showed similar findings. Researchers instructed 40 healthy men in their 20s to perform resistance training at least four days per week for eight weeks. One group consumed 25 g of whey protein immediately before and after exercise, while the other consumed it three hours before and after. Both groups increased muscle mass, strength, and exercise performance. The researchers concluded that the key factor in maximizing muscle protein synthesis is adequate protein intake alongside resistance training, and that timing plays a relatively minor role.

Another common misconception is that eating too much protein at once is "wasted," and that only 20–25 g per meal can be used for muscle protein synthesis, with anything beyond that turning into fat. This leads to the belief that three protein-rich meals are always better than two. But this is also false. When large amounts of protein are consumed, the body simply slows digestion and amino acid release, allowing gradual absorption. The old "25 g limit" came from studies where subjects consumed rapidly absorbed whey protein without any other food. Real meals are far more complex -- eating rice and side dishes slows digestion and amino acid absorption significantly.

Our bodies are smart and efficient. Muscle protein synthesis doesn't only occur immediately after exercise -- it continues for many hours. You can drink a protein shake after working out or simply eat a whold food meal. Although spreading protein across meals can be helpful, skipping breakfast and eating more protein at lunch is not harmful. The protein you consume will be used one way or another -- for maintaining muscle, supporting strength, immunity, hormone production, and metabolism. There is no need to obsess over timing; focusing modestly on total daily protein intake is enough.

However, remember this: eating protein without exercising is not enough. According to the National Health and Nutrition Survey, only 27.3 percent of Korean adults aged 19 and older performed strength training at least twice a week in 2023. Make exercise a priority.

Jeong Jae-hoon is a food writer and pharmacist. He covers a variety of subjects, including trends in food, wellness, and medications. This column was originally published in Korean in Joongang Ilbo on Nov. 6, 2025. -- Ed.