It's the caffeine in the coke propping you up, I think. You are essentially making a speedball.

Having said that - I like a cocktail in the weekend (one double so two of yours not 7, holy shit that is binge drinking and definitely not good if you are prediabetic! I'd be under the table before the last one) and my husband does prefer a couple beers and he is snoring on the couch by the evening, I don't feel so tired. So maybe you are on to something.

How is whiskey and diet coke? That doesn't sound very good, though I like each of those separately. Like I think I'd prefer tonic or just fizzy water and lime with whiskey. When you are willing to have fewer come on over to !cocktails@lemmy.world and make something fancy, I'm sure less carbs in one nice drink than 7 shots!