I'm a firm believer of exercising first thing in the morning, for a number of reasons. Over 90 percent of people who exercise consistently, do it in the morning. The odds of sticking to an exercise program are far better if you chose to exercise first thing in the morning.
Aside from consistency there are many other good reasons. Exercising first thing in the morning "jump starts" your metabolism and keeps it elevated for the following hours of the day. That means the calories you consume during the day have less chance of being stored as body fat. Also, exercising first thing in the AM will give you an energy-boost and regulate your appetite for the rest of the day.
A very important but often overlooked reason for exercising in the morning is you then have the rest of the day to feed your muscles quality nutrients to speed recovery and provide the building materials for muscle growth. Training in the late afternoon robs you of the ability to provide steady-state nutrition because a few hours later you're going to bed and essentially fasting for 8 hours or so. You're depriving your muscles the nutrients to fuel the recovery and growth from your training.
Finally, this last aspect is vital to achieving results. Research shows that people who feel good about themselves make better food choices. Nothing feels better than completing an awesome workout. Training in the morning gives you this feeling the rest of the day. This helps keep you focused on your nutritional needs and goals.
