A lot of people have been asking me recently specifically about issues with working out first thing in the morning, how soon to workout after eating, etc. so I thought "pre-workout nutrition" would be a pertinent topic for a blog post. I just have to say before I start that unfortunately information about diet and nutrition seems to always be changing. For example if you read two consecutive editions of Men's or Women's Health magazine, you will probably see articles that contradict each other. From my own research, and some of the latest scientific studies I have read in journals and heard on NPR for example, I'd like to claim what I'm going to say today, to the best of my knowledge, is up to date and will help you achieve results!
A starting place: Your body's energy sources during a workout
When you begin strenuous activity, depending on the intensity level of the workout, your body will basically use the most easily accessible source of energy to fuel your workout. For short bursts of activity, your body has about 10 seconds worth of ATP stored in what is known as the Phosphocreatine system. This system is anaerobic and isn't fueled by nutrients of food, but rather adenosine diphosphate and phosphocreatine undergo a chemical reaction which nets one adenosine triphosphate (ATP) - the body's energy molecule. Other sources of energy are carbs, primarily as glycogen, which is stored carbs in the muscles and liver, and of course, fat. The bloodstream can carry a small amount of glucose for energy, but not more than 20-30 calories, so the majority of carb energy is from glycogen, which is the stored form of glucose. Think of glycogen as ice to glucose's water. The more strenuous the exercise, the higher the glycogen/fat ratio usage ratio will be. With p90x and Insanity for example, you are using about 75% glycogen and 25% fat for energy because you are mostly in your anaerobic zone (+85% max heart rate). Glycogen is a limited, but renewable source in the muscles while fat is generally used as "long-term" storage and is stored over time.
If glycogen stores are completely or nearly depleted, your body goes into ketosis, which means it begins breaking down only fat in place of glycogen. This breakdown of fat will leave freestanding ketones (the acidic bodies that are the "waste" of fat breakdown in the absence of carbohydrate) in your bloodstream, which is why you may smell ammonia when you are in this state. You might think ketosis is a desirable state to be in to lose weight, but it certainly isn't a good place to be in during an intense workout, since you will most likely be crashing at this point and won't have enough energy to complete the workout! If you are looking to hone in your metabolism and build lean muscle, working out in an anaerobic state while glycogen is still available is still your best option. Most people have about an hour of anaerobic training worth of glycogen stored up in their body, but everyone is different. Also note that even in aerobic exercises, both the glycogen and fat burning systems are occur. There is a saying "fat burns in a carbohydrate flame" which notes that the reactions of glycolysis are necessary as part of the reactions that occur in the mitochondria for fat breakdown. Again, when in ketosis, the glycogen system is compromised.
Also note, when you are in a purely anaerobic state, you might only be able to last for 2-3 minutes before the lactic acid build up becomes too painful to continue. That is why most anaerobic workouts are interval workouts where you go hard for short bursts followed by moderate activity or full rest to recover.
How digestion affects circulation during a workout
After eating a meal, your body almost immediately begins the process of digestion. When you are digesting food, blood rushes to the digestive organs to aid in the process, which means less blood is readily available to aid the brain and muscles during a workout. It is therefore very important if you are concerned with maximal performance, that you don't eat a huge meal right before a workout! The general guidelines are: don't workout within 4-5 hours of a big meal full of protein and low-glycemic foods, don't workout within 2-3 hours of a medium sized meal, or meal with medium-glycemic foods, and don't workout within 60-90 minutes of a small snack, even a high-glycemic snack.
Conclusion #1: Relating to working out first thing in the morning
When you workout first thing in the morning, both of the previous two points come into play. You will not have much glucose in your bloodstream, so therefore your body will be going for stored energy immediately. Since you haven't eaten anything for, most likely, at least 10 hours, you don't have to worry at all about digestion getting in the way of working out. This seems like an ideal situation, but most things that look too good to be true usually are.
One problem with working out on an empty stomach is that often you will not have the energy to maximize your performance, but that differs from person to person. If you are going for a jog, or performing another mild aerobic activity, it might be OK to go on an empty stomach. However, if you are doing an intense workout first thing, having low energy might reduce the number reps you can perform, and therefore the amount of calories you burn. Most people will have enough glycogen to get through a morning workout "on empty," but realistically you need to know your own body and figure out what works for you in this situation to be safe.
How the body stores energy before vs. after a workout
I'll touch on this more next week, but basically what you need to know is that your body stores energy (food) differently before and after a workout. When your body is depleted of glycogen because you have just performed strenuous activity, your body uses food to replace glycogen stores and less will get stored as fat. By contrast, if you eat a high calorie, or even worse high calorie/high glycemic meal, and are sedentary for most the day (or if you eat a high calorie meal before bed) your body will most likely store most of this energy as fat. Your body is interested in long-term preservation - it knows if you have enough fat stored, you can survive and "live off the land" if you find yourself in a dire situation.
Makeup of pre-workout meals
First - the myth that you need to "chug" protein drinks before workouts should be debunked once and for all. Protein is extremely important for building muscle and maintaining metabolism, but it basically just has to be in your body from any point in the day - taking it in right before a workout doesn't really make a difference. Whey protein is OK as a pre-workout source since it absorbs quicker than any other protein source, but it's not going to maximize your muscle gains much more than an apple right before a workout would, as long as there is consistent protein across your entire diet. Carbs are also important (they are not "the devil" like most popular culture references would imply) since they will help maintain glycogen and digest quickly for immediate energy throughout the day. Low-glycemic carbs like some fruits, vegetables, oatmeal, quinoa, and other whole grain sources are perfect for meals hours before working out, and higher-glycemic carbs are really only suitable post-workout, or in very small doses if you can only fit a quick snack in an hour or so before the workout (see next section). So the rule with pre-workout nutrition is basically that of my general eating philosophy - go for balance. I love 40/40/20 protein/carb/fat ratio. Considering what the average American eats, that is probably more protein than you already are eating!
One more factor: Cortisol Levels and the catabolic process
Cortisol is essentially the "stress" hormone produced by the body. When your body undergoes emotional or physical stress, cortisol is released. This is an overly simplified sentence, but basically you don't want to have an overdose of cortisol in your system. While in small doses it relieves pain (example: a cortisone shot used on athletes), in large doses it can actually inhibit the muscle building process and increase storage of fat. When you workout to the point of ketosis, your body is certainly undergoing major stress and you release a lot of cortisol from the adrenal glands. Additionally, some studies have shown that eating a lot of high-glycemic foods (and even Whey Protein, which isn't necessarily high-glycemic, but is fast to be absorbed) directly before a workout, while they are great sources of immediate energy, they will raise cortisol levels during and after the workout. Obviously, there is a balance between these two scenarios - you shouldn't be working out to ketosis on a regular basis, and shouldn't be binging on simple carbs before your workout! It should also be noted that just like you build up a tolerance to lactic acid over time when you work out (runners especially know what I'm talking about) your body will regulate cortisol better the more you workout.
Knowing the day's natural cortisol cycle is important as well. Cortisol levels peak between 9 a.m. to 12 p.m. (depending on when you wake!) and then steadily decrease from mid-afternoon into the night. Sleeping well is important in cortisol control, and working out before the early afternoon is perhaps smart, so that your body's natural cortisol cycle will be preserved. Working out later in the day will spike cortisol again into the later evening which isn't advisable, as it could keep you up late.
The Bottom Line
-Workout 4 hours after a big meal, 2-3 hours after a medium meal, and at least 60 minutes after a small, simple carb snack
-Working out in the morning before any food is a double edged sword. Yes, you will be targeting stored energy more readily, but you might not have the energy to complete the workout. A small, simple carb snack is advisable before the workout, but don't make it too big or too close to the workout as this could spike cortisol levels
-Always go for a balanced 40/40/20 protein/carb/fat meal before a workout. Yes, protein in your diet is important, but not at the cost of eliminating healthy carbs and fats, and it isn't necessary to load up on protein right before a workout
-Try to workout before 2:00 p.m., as you will be in phase with your body's natural cortisol cycle
Some eating/working out schedules that work
Here are a few schedules that include when to workout and meals around the workout
1) This one is my favorite, and one I did most of last year, and honestly the one which gave me the best results. Because of life, I have to workout earlier in the day now, but am looking forward to when things slow down in the summer so I can go back to this schedule!
7:30 Eggs and oatmeal
10:00 all-natural granola bar
12:00 Recovery Drink
1:30 Salad with protein (fish, chicken, etc.)
2) This is my current schedule
7:00 Half serving of Oatmeal
9:30 Recovery drink, greek yogurt with GoLean cereal, one hardboiled egg
12:00 Salad with protein
3) The Lorraine schedule (my awesome friend!). She has to workout early in the morning because she has "real-person job", but doesn't want to be on complete empty when she starts. I illustrate this mostly so you understand it's important to hold off on the big breakfast until AFTER you workout.
5:00 Light carb snack and/or little bit of whey protein
5:15 Workout (weight training or run)
6:15 Recovery Drink
7:30 Full breakfast (oats, berries, flax seed, egg whites!)
4) Doubles schedule: I actually did this for a while in November and December
7:30 Full breakfast
10:00 Granola bar
12:30 Salad w/ protein, and carb portion of something
5:00 p90x workout
6:00 Recovery drink
5) Finally, if you have to workout at night here is a good way. If you workout late, I assume you don't go to bed too early, hence the 8:00 dinner:
8:00 BIG breakfast (I mean BIG!! COMPLEX CARBS INCLUDED)
10:30 Snack I
1:00 Salad with protein
3:30 Shakeology or other snack
6:30 Recovery Drink
8:00 Dinner (mostly protein, healthy fat - don't want to load up carbs before bed)