Lactic acid is a colorless, syrupy liquid that forms when the body breaks down carbohydrates for energy during intense exercise. It is produced in the muscles and can lead to a burning sensation when you push your limits. This process is part of how our bodies generate energy without oxygen, known as anaerobic respiration. In addition to its role in exercise, lactic acid is also found in various foods, such as yogurt and pickles, where it acts as a preservative and adds a tangy flavor. It is produced by lactic acid bacteria, which are essential in fermentation processes.