The meaning behind HONEYMOAN's song "Gym Song" is about a relationship where one partner becomes obsessive with their fitness and diet, causing them to miss out on social events and only talk about their fitness plan. The lyrics express concern about the unhealthy behavior and lack of variety in conversation. It highlights the importance of balance and openly communicating in a relationship. The chorus repeats the phrase "ultimate sport nutrition" sarcastically, mocking the obsession. Ultimately, the song is an intervention for the partner to reconsider their priorities and find a healthier balance.