If you ask any expert fat loss fitness trainer San Diego professional whether or not it is better to exercise on an empty stomach, or after eating, you will most likely receive conflicting opinions. As with most things in life, there are convincing arguments for both sides. This leaves the general fat loss seeking individual confused, and sometimes paralyzed at the thought of having to pick a side. I wanted to share some interesting results from research studies conducted to find the solution to this often debated over topic, and then share my take on what I recommend to my fat loss personal training San Diego clients.
Research in favor of training on a fasted state
A 2006 study looked at moderately trained subjects during a 2 hour moderate-intensity cycling workout and found that ingesting carbohydrates before training suppressed fat oxidation and other markers of lipid metabolism in both women and men compared with training in a fasted state.
A previous study in 1997 looked at more trained subjects who completed a low intensity workout, and discovered that consuming carbohydrates ahead of time significantly inhibited fat oxidation compared to cycling in a fasted state.
Research in favor of eating carbohydrates before exercise
A study in 2000, found that trained cyclists who consumed carbohydrates before a moderate pace workout saw an improvement in performance without concurrent decreases in fat oxidation.
Another study in 2011, had trained subjects complete a moderate paced treadmill morning run on a fasted and fed state. They found that when subjects were fed prior to the run, fat oxidation rates were higher 12 to 24 hours after exercise but not during. In addition, the fed subjects had higher oxygen consumption during and 12 to 24 hours after exercise indicating greater calorie expenditure. This shows that while eating beforehand may blunt fat oxidation during the bout, it may increase over the rest of the day in addition to caloric expenditure.
My take on everything
Everything becomes a case by case basis. When working with a personal training San Diego client, I take into consideration their fitness level, eating habits, and schedule availability for workouts to determine the best advice for them. In general, if a have a client who is novice to exercise I suggest they take long walks in the morning or may have them complete 20-30 minutes of moderate exercise in a fasted state. Anything longer than 30 minutes of moderate activity or with anaerobic intervals I will suggest they eat at least 1-2 hours prior to exercise. For more trained clients, I will always suggest the eat 1-2 hours prior to exercise. As with more trained clients, I am coaching them for not only fat loss but overall performance. I have found that performance is always sacrificed when training on an empty stomach, and the overall benefits are not sufficient enough to support the recommendation.
I hope this helps give insight into the best training state for you and your fitness goals!