I watched a BBC documentary which did endorse your point about alchohol unleashing creativity. But ONLY at very low levels, e.g a glass of wine. And I certainly wrote some dazzling essays for my English degree. BUT, again, only at a low level. If I wrote when I was drunk, I felt like I was a genius. However, when I would read them back the following day I wanted to die! And if you are an alcoholic like me, you can't stop at one drink. And alcoholism is a progressive condition - it always gets worse, you always need more and more.
At 40 you are still young. Plenty of time to get sober, and enjoy writing naturally. The block will soon go as you get healthier, and so will the extra weight.