I. TIMING NUTRIENTS PRE-WORKOUT
Most of the information that has been written on “nutrient timing” has to do with pre and post workout nutrition. The reasoning behind this stems from serious gym-goers and bodybuilders that are most concerned with optimizing performance and nutrient intake. The same would hold true, of course, for more serious athletes—pro football players, Olympians, etc.
As part of your pre-workout routine, we want to make sure we have a readily available fuel source, so that carbohydrates metabolize into sugars and sit in the blood stream as glucose. Therefore, as a pre-workout snack/meal we want to make sure we get in a certain amount of carbohydrates.

The carbohydrate source should be low-glycemic and fairly slow digesting. If you eat a rapidly digesting carbohydrate, 30 minutes before you weight train, your blood sugar levels will spike and your pancreas will release insulin to pull the sugar out of the blood stream. Once you start exercising, your body will rapidly become hypoglycemic, and you will feel dizzy, nauseas, and have to end early. The goal is to eat the right amount of pre workout carbohydrates that will digest at the perfect rate – not too fast, and not too slow.

You will still want to include a protein source (albeit a smaller serving) pre-workout; as this will still help to slow the digestion of the carbohydrate, and allow a steadier release of nutrients, thus helping to maintain fairly stable blood sugar levels throughout the workout.

This is much more important when dealing with weight training, which is anaerobic in nature. Cardio, by contrast, is aerobic. If I have a client whose main goal is fat loss, and they are simply doing a cardio session, then I would not want them to consume carbohydrates prior to coming to the gym. If they have high glucose levels actively floating throughout the blood stream when they begin their cardio, it’s going to take the body that much longer to burn through it before their body starts tapping into fat stores. This explains why most bodybuilders, when performing cardio for fat-loss purposes, try to get it in either first thing in the morning, or post-weight-training. Those are the two times of day when blood sugar levels are at their lowest, and thus the body is going to preferentially burn more fat than it would at other times throughout the day.

II. TIMING NUTRIENTS POST-WORKOUT
While carbohydrates are important pre-workout, they are even more important post workout. I would make the claim that if you only were ‘allowed’ one carbohydrate meal throughout the day; it should be after a hard workout session. When you workout hard, you tend to burn off all of the sugar available in your blood stream (glucose), and also burn through a good amount of the stored sugar in your body (glycogen). You also tend to beat up your body, tearing down muscle tissue, elevating adrenaline and cortisol levels, and a host of other processes that are catabolic.

Catabolism – promoting the wasting of muscle tissue
Anabolic – promoting the healing or growing of muscle tissue

Post-workout, the body’s first concern is to get out of the catabolic state you have just created. Basically, you just beat the living crap out of your body, and it is freaked out. Its first concern is to make sure everything is going to be okay, therefore, until you have replenished baseline levels of nutrients, such as replenishing glycogen, it is certainly not going to be concerned with synthesizing new tissues (new muscle). Hence, the most important nutrient post-workout is carbohydrates. Another way of putting it, insofar as, if you’re going to eat carbohydrates, you should be eating most of them around your workout, pre and post, with post workout being even more important than pre workout on average.

Of course, this is all still relative to the goals that you have set for yourself. As a bodybuilder, if I am in a phase where I am actively trying to pack on as much muscle mass as possible in a short time frame, and I am not overly concerned with gaining a little body fat, then I am going to err on the side of consuming more carbohydrates and intentionally spiking my insulin levels. This is going to help drive amino acids and glycogen into the muscle cells and optimize recovery and growth. If, by contrast, I’m in a “cutting phase”, where I am actively focused on losing body fat and doing everything in my power to get ‘ripped,’ then I am going to restrict my carbs more (and nutrients/calories in general). Therefore, I’m going to err on the side of caution when it comes to how many carbs I ingest both pre and post workout. I am also going to limit them a lot more, insofar as, I’m still eating carbs, and I’m going to try to make sure I get in a good amount of them pre- and post-workout; but overall levels will definitely be lower, because my goal is different.

This often explains the promotion going on at the Lifetime Fitness Café, “Optimize in 45.” It’s basically the idea that you have a 45-minute window post workout to optimize recovery and growth, and therefore, you should get in a recovery meal with the proper ratio of nutrients. The general recommendation by most nutritionists is that your recovery meal or shake should consist of either a 3:1 or a 4:1 ratio of carbs to protein. With clients that are trying to lose weight, I usually err on the side of a 2:1 ratio of carbs to protein.

Above all else, I should also point out the irony of how most people think about nutrients: most people consider protein to be the most important nutrient to consume pre and post workout. Protein is your most important nutrient throughout the rest of the day, not an energy source, but a building block. While working out, your body is not building, it is tearing itself down, and therefore, you need energy around your workout. Don’t get me wrong, you still want to get in the appropriate amount of protein pre and post workout, but it’s simply not as important as your carbohydrate intake, as long as you are aware of the levels.

III. CARB INTAKE THROUGHOUT THE REST OF THE DAY
There is a lot of debate in the exercise and nutrition world as to whether timing of carbohydrates matter for fat loss or muscle gain throughout the rest of the day. Because nutrient timing is generally accepted as gospel amongst most bodybuilders and physique athletes, I would like to subject others want to get fit to the theories. From a scientific standpoint, it makes sense to try to time your carbohydrate intake throughout the day. We’ve already seen that the a good chunk of your carbohydrates should be ingested pre and post workout – especially during harder resistance training sessions. This is due to the fact that carbohydrates are a fast energy source, meaning they metabolize into sugars that sit in the bloodstream, available for immediate use.

What we can deduce from this, is, that carbohydrate intake, in general, should reflect activity levels. In other words, if you eat a lot of carbohydrates and are sedentary, chances are you are not going to immediately burn them off, and if you don’t immediately burn them off, you are going to store them. The body will first store those carbs in muscle tissue and the liver, provided there is room. Once there is no more room (i.e., you’ve eaten too many carbs throughout the day, or over a certain period of time, without enough activity), then the body is forced to store the carbs in adipose tissue. Therefore, you have a lesser likelihood of storing carbohydrates as body fat if you eat them during times when you are more active. In other words, you want to try to get your carbs in earlier in the day, and taper them off as the day progresses.

A lot has been made about the idea that “you shouldn’t eat past 6pm” (or fill in whatever magical time you adhere to). Oprah has made a big deal out of this principle. In general, I’m sure there is a correlation between limiting feeding times (i.e., stopping food intake a few hours before bed) and weight-loss. After all, most people get the hungriest for ‘bad’ (high sugar, high fat) food when they are winding down, trying to relax and getting ready for sleep. Therefore, if you consciously abide by a rule that prohibits you from eating the wrong foods at times when your body will wreak the most havoc with the nutrients, then chances are good that you will be more successful with your weight loss.

However, it all comes down to what you eat late at night. Personally – and every other bodybuilder and physique athlete that I know – eats right up until bed time. It’s that last meal or two consist almost exclusively of lean proteins, vegetables, and maybe some healthy fats. We tend to taper carbs off later in the day or early evening, often following a “carb-cutoff” rule that is implemented, which should reflect your schedule. For example, so if you tend to go to bed around 11pm, your “carb-cutoff” time might be 6pm – that is the time of day when you allow yourself your last meal with carbs, and any food you eat beyond that is going to be simply protein and veggies.

Eating protein meals before bed might not sound super glamorous or appealing, but it serves specific purposes that can be very advantageous to weight loss. First, protein digests into amino acids, which cannot be stored in the body for future use. If you want to have the necessary nutrients (amino acids) available to help repair tissues (i.e., muscle tissue, damaged from weight training), then you need to eat protein sources within fairly small windows (more frequently, the better). Therefore, if you have your last meal at, 6pm, go to bed at 11pm, wake up at 6am, and eat breakfast at 7am, you have now gone 13 hours without a protein source, which means there are NO amino acids available in your bloodstream to help with muscle repair. If you are actively trying to build muscle (which, will help immensely with fat loss and help you lose the weight you want to lose), you have just starved your body of the nutrient it needs for repair (amino acids, or protein) during the hours when it wanted to do most of its repairing. I think it always makes sense to try to get in a late-night protein meal or snack (cottage cheese, yogurt, whey protein shake, salad with chicken in it, etc).

Second, having that late-night meal, even if it’s not the tastiest or most appealing option in the universe, will help to keep you full, so you are not hungry and craving other less-nutritious foods. It is better to eat something, and give your body the nutrients it can actually use for positive benefits, than to starve it of those nutrients. Moral of the story: try to make your earlier meals in the day protein-carb based, and your later meals in the day either protein-veggie, or protein-healthy fat-veggie based.

IV. TIMING CARB AND DIETARY FAT INTAKE
Another hotly-debated topic, within the nutrition world, and worth discussing – many people think you should try to separate the ingestion of carbohydrates and dietary fats. Carbohydrates, especially in larger portions, tend to elevate blood sugar levels, which leads to the release of insulin. Insulin works as a “shuttle” nutrient. Think of it as the bus-driver that drops off everybody where he or she is supposed to go. Higher insulin levels help to drive carbs into the muscle cells as glycogen, amino acids into the muscle cells to help build new muscle, and creatine into the muscle cells. Many think, that insulin will also help to drive dietary fat, in the form of triglycerides, into adipose (fat) tissue. Therefore, many advise against consuming meals that are both high in fat and carbs.

Also, remember that both fat and carbs are energy sources. The body only needs so much energy at once. If you provide it with too much, and it simply can’t use it all, therefore, you generally don’t want to be consuming a lot of fats along with your carbs all at once. It’s no coincidence, in my opinion, that the foods that tend to be the worst for you tend to be highest in both fats AND carbs – pizza (cheese and bread), ice cream (dairy and sugar), desserts in general (butter and oil, along with tons of sugar and starch), etc. For these reasons, start thinking of your meals as partitioned into either protein-carb meals, or protein-healthy fat meals, or protein-veggies meals.