You can do much to take advantage of the dynamics of food and fluid consumption in relation to sports and exercise performance, including weight training and muscle building.
Meal Timing and Sports and Exercise Performance
Since essential nutrients, such as carbohydrate, protein and fat, provide energy for the body, when you provide these nutrients — and to a lesser extent in what form you provide them — can influence your performance either in training or during an event. This is not just a theory, it is the cornerstone of modern sports nutrition with science to back it up.
The essential elements of meal timing for exercise performance are:
1: The pre-activity meal, including fluids
2: Food and fluids during the activity
3: The post-activity meal and fluids
4: Total food consumption over 24 hours, especially carbohydrates
These factors need to be adjusted for energy intake and expenditure according to any particular session, sessions over 24 hours and extended training periods.
How you should eat to maximize an average weight training session is necessarily different from eating to maximize a lengthy endurance training run, swim or team sports session that may involve more or less continuous exercise for two hours or more. Such activity involves a much higher energy expenditure and a food intake to match.
In this article, I’ll concentrate on weight training and bodybuilding while providing an overview of meal timing in sports nutrition.
Myths of Meal Timing and Eating:
There are several recommendations from various fitness and training sources that have little basis in fact, even though they are mostly impractical rather than harmful. These myths are widely disseminated and repeated.
Myth 1. You should only eat grains, starches and sugars near to your training session and eat fruits and vegetables at other times during recovery. This advice says that exercisers should only consume grains and starches (i.e., bread and oatmeal) for breakfast or in recovery from an exercise session. At other times, they say, your carbohydrates should come from fruits and vegetables. I’m not sure where this idea came from — Paleo diets perhaps — but for men and women doing “serious” training, the demand for energy is too great and grains and starches (and sugars) are the number one form of food energy. Often, the main problem is eating enough, let alone being picky about different carbs.
Consider this example. Doing five or six 90-minute sessions a week at an energy expenditure of around 1,200 to 1,500 calories per session is not a trivial amount of energy to replace. That’s about 6,000 to 7,000 calories per week, conservatively, in addition to your resting energy expenditure. (Resting energy expenditure or resting metabolic rate (RMR) is the amount of energy you use for basic functions such as breathing, digestion, and brain activity, while at rest.)
Let’s say 5,000 of those calories are in carbohydrates. At 4 calories per gram of carbohydrate and 15 grams of carbohydrate in the average slice of bread, that’s approximately 83 slices of bread a week or the equivalent that you would require to fuel that quantity of activity. That’s a lot of fruit and vegetables you would need to eat … and, frankly, I don’t want you exercising next to me at the gym unless you have very good bowel control.
It’s just not feasible for most heavy trainers — although it may be possible — to meet those demands without snacking on bread, pasta and sugars randomly over the course of refueling and pre-fueling over 24 hours. In fact, some high-level athletes – swimmer Michael Phelps was a good example – might need 6,000 to 7,000 calories a day!
I’m suggesting that you don’t get carried away with some silly eating protocol because a so-called “authority” said it on a web site — even this one, except I’ll back it up with logic and references. If you’re a bodybuilder or casual fitness trainer, you may get away with a protocol that restricts grains and starches, but I don’t see the point. Whole grains are associated with lower rates of heart disease and diabetes and probably bowel cancer. Even refined and high-GI carbs (such as added sugar and white bread) are easily assimilated and provide valuable and convenient refueling for athletes.
Myth 2. You should eat six small meals each day instead of three main meals. I think the idea here is that insulin will be kept lower by keeping meals small and that this will also reduce appetite and assist with weight management. There is no solid basis for this. Insulin may even function better with fewer, rather than more, regular meals. Even so, if you’re a big athlete exercising hard, you may need to spread out your meals just to be able to consume the quantities of food required.
The Pre-Exercise Meal
Firstly, it’s not a good idea to exercise hard on an empty stomach, even if you want to burn off some fat. Fat burning evens out over the day in any case. What you need to watch is your calorie intake and activity expenditure over 24 hours. Even allowing for that, there are several reasons why exercising on an empty stomach may not be ideal, especially at the extremes of fasting and exercise.
Hard exercise sessions with low blood glucose raises the stress hormone cortisol, and at the extreme, can lead to immune system suppression and the onset of opportunistic infections, such as flu and sore throat.
Similarly, in this state, muscle is more likely to be be broken down than when blood glucose is maintained at a higher level.
Let’s assume an average session is approximately 75 to 90 minutes, including 20 to 30 minutes of cardio. The remainder is a series of weights sets and repetitions at various intensities and perhaps some circuit activities. This would be a very solid session and some will do less than this on average.
Ideally, a main meal should be taken 3 to 4 hours prior to your training session, and you should top up with something 45 to 75 minutes before the training session, depending on how you tolerate food in the stomach when exercising. As you get closer to exercise, fluids, such as sports drinks and simple carbohydrates, will sit better and digest faster. Training early in the morning can obviously make this timetable problematic, and you may need to take more sustenance during exercise.
Your pre-exercise meal should include protein and carbohydrate. Recent research suggests that a small quantity of protein taken after a weight training session helps with protein assimilation and muscle rebuilding in the recovery phase. Less established is a requirement for protein before exercise, although some research suggests a small amount may also assist overall recovery. You don’t need much protein to stimulate this effect: 10 to 20 grams is all that’s required. A glass of skim milk has about 10 grams of protein. You really don’t need expensive protein powders either, although they won’t hurt.
The amount of carbohydrate you should eat before training depends on the duration and intensity of the exercise session or event and time since the most recent full meal. Naturally, unlike a marathon runner, you don’t need to load up on carbs before a weight training session. Some carbohydrate, though, in the form of a shake or a few pieces of toast or cereal should be enough to keep blood glucose from dropping too low during the session. In both cases — protein and carbs — choose something that you know your system will tolerate well. This can be a matter of trial and error. High-fiber foods, such as fruit, beans and high-bran cereal may not be ideal for some people. Some individuals have a fructose sensitivity, so fruit or sugars may not suit them.
Drink sufficient fluids so that your urine color is a light lemon, and not a dark yellow. This will tell you that you are well hydrated. You don’t need your urine color to be completely clear.
Refueling and Rehydrating During Training:
Fluids and fuel. If you plan on training for longer than an hour at a reasonably high intensity, you should take about 400 milliliters (14 fluid ounces) of a sports drink (about 7% carbohydrate and 25 grams of carbohydrate) every 30 minutes. If it’s very hot and you sweat profusely, you may need a little more fluid, but not too much more. This will keep blood glucose topped up nicely, and you won’t drain your muscle glycogen stores as quickly — enabling you to perform better — and you won’t get in to a catabolic, high-cortisol state, where muscle and immunity could suffer.
Post-Exercise Refueling for Weight Training
Here’s the best approach to refueling and rehydrating after your weights session based on current evidence in sports medicine.
In the first hour or so, try to drink enough fluids to recover what you have lost plus 50% on top of that to compensate for the post-exercise energy expenditure, especially if you plan to train again that day. You can measure fluids lost by body weighing before and after. Weight training is not that critical an activity for fluid loss, so just be sure you stay hydrated without drinking too much, which can also be dangerous.
Consume 10 to 20 grams of protein with carbohydrate within 30 minutes of your session. Aim for a maximum of .8 to 1.0 grams per pound of body weight per day in total protein consumption. Less may be appropriate for lighter training programs.
Consume 50 to 100 grams of carbohydrate soon after your session. Two slices of bread and honey is about 50 grams. A 600 ml sports drink is about 40 grams. Subsequently, eat as much carbohydrate to fuel your activity over the duration of your training and competing. For general fitness training, weight training and bodybuilding, the requirement will be in the range 2 to 3 grams of carbohydrate per pound of bodyweight each day of training. (Endurance trainers, such as marathoners and triathletes usually require much more than this.)
For best results in providing energy during your training or competition and to maximize body composition, the general approach described above should be effective. You should fine-tune these recommendations, though, to suit your own training and personal characteristics for best effect.
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