Morning vs Afternoon vs Evening Workouts
The great debate...I've done them all and there is an easy answer here, no need to make this complicated.
Why are afternoon workouts (4pm to 7pm) the worst? Its because you're fucking tired. You've likely worked all day long and now you're going to try to push your body to the limits to either build muscle of burn fat? Ya sounds like a GREAT idea. Let's try to focus all day on all the meetings, and numbers, and powerpoints, and spreadsheets, and emails. All that high frequency mustard shit. Then try to go work out. Ya fuck that.
Why are evening workouts (8pm to 11pm) actually awesome? It's because evening workouts can be the cleanse of the day. Frustrated about that jackass at work? Go to the gym and release that frustration. Then after you've burned through the stresses of the day you can go home, down a protein shake, and go straight to sleep. This gives the added benefit of resting immediately after your workouts to maximize recovery.
Why are morning workouts (4am to 9am) the best? There's a reason Navy S.E.A.Ls like Jocko Willink wake up at 4 am and start their training. I believe it's for 2 reasons. First, your testosterone levels are highest in the morning so you are able to maximize your effort and muscle growth. Second, if you get a workout in before 9am you can easily add another workout later in the day, typically some lighter cardio. Another added benefit of morning workouts for us mere mortals (who are not elite warriors) is we are likely headed straight to our office job after our morning workout where we likely will sit and answer emails or listen to pointless meetings for 8 hours. What we're actually doing though is maximizing our recovery all day long, while Kevin explains how IBM is poised for a 15% upside....No Kevin IBM isn't going to climb 15% this year, just buy it for the dividend and give it to your grandkids.
Conclusion: Mornings...and Evenings if you're a 2-a-day kind of guy.