I have been working out on empty stomach (took only beta alanine, coffee and bcaa) for several months now. I remember feeling weak and tired when I first started. But over the time I think my body adapted to it, and did not feel weak or tired. I had lots energy and strength to do workout. But yesterday I ate one banana, half cup of oat and a scoop of protein about 1.1/2 hour before I went to gym. And had worse workout of my life. I felt so uncomfortable and weak. I couldn't even perform bodyweight pull ups of 4x6. By the time I got to my last set, I was so tired. I thought carbs and protein are supposed to give strength to perform your workout. Did any of you ever have this kind of experience?