Post-workout nutrition is one of the hottest topics in the fitness field. I’ve discussed this topic in a previous post. But what about before training? Is there anything special you should eat?
The main nutritional goal pre-workout is to supply adequate energy for your muscles and brain during training. This makes carbohydrate consumption essential. Carbs are stored as glycogen in your liver and muscles. Since high intensity exercise utilizes energy at a very fast rate, the body can’t supply enough oxygen to harness fat as a fuel source. Thus, it relies on its glycogen stores, which don’t require oxygen to be broken down for energy.
By taking in carbs before exercise, you ensure that you’re body’s glycogen stores are fully stocked. With a ready supply of glycogen, your muscles can access energy on demand. In this way, you’re able to go all-out in your training efforts, extending performance without “hitting the wall.”
Protein should also be included in your pre-workout meal. Although it doesn’t contribute much in the way of energy, consuming protein prior to exercise has both anabolic and anti-catabolic effects. Recent research has shown that, by providing a steady stream of amino acids at the onset of training, you maximize their delivery to working muscles and thereby attenuate the breakdown of muscle tissue during your workout. Moreover, you significantly increase muscle protein synthesis in the first hour after exercise, priming the body for anabolism.
The consumption of fat, on the other hand, should be kept to a minimum in the pre-exercise period. Fat delays gastric emptying, thereby prolonging the time it takes foods to digest. If food sits in your stomach during exercise, there is an increased likelihood of gastric problems including cramping, nausea and reflux.
For best results, try to consume your pre-workout meal approximately two to three hours before training. Allowing a couple of hours between the end of your meal and the onset of exercise will ensure that the majority of your meal is digested and help to prevent gastric upset. Stick with slow burning carbs and lean sources of protein. Oatmeal and egg whites, tuna on multi-grain bread, lean steak and yams, chicken breast and brown rice are all terrific options. Total calories should be about the same as in one of your “regular” meals. This will provide adequate fuel without bogging down your stomach.
If you aren’t able to consume a full meal in the prescribed timeframe, opt for a piece of fruit within a half-hour of your workout. Due to a high concentration of fructose, fruits are low on the glycemic index. This is significant because it keeps insulin levels stable, thereby preventing the potential for rebound hypoglycemia—a condition that can result in lightheadedness and fatigue. At the same time, fruits provide a valuable source of fuel during exercise, improving your capacity to train.
Ideally, the piece of fruit should be combined with a whey protein drink. Whey is a “fast acting” protein, meaning it’s rapidly absorbed into circulation. This expedites the flow of amino acids to your muscles without having an appreciable impact on digestion. Aim for about one-tenth of a gram of whey per pound of body weight (i.e. a woman weighing 120 pounds would need about 12 grams of whey) mixed in a water-based solution.
The pre-exercise period is also a great time to have a cup of coffee. Caffeine acts on the sympathetic nervous system to increase catecholamine (i.e. epinephrine and norepinephrine) production. Among their diverse functions, catecholamines mobilize fatty acids from adipocytes (i.e. fat cells), allowing them to be utilized for energy. And since exercise increases caloric expenditure, the body can make immediate use of these fatty acids to fuel your muscles. At the very least, it can help to expedite exercise-induced fat loss.
I will be presenting my “Facts and Fallacies of Fitness” seminar at the upcoming NSCA National Conference, debunking many of the common myths about exercise and nutrition. The conference is being held at the Walt Disney World Swan and Dolphin Resort Hotel in Orlando, Florida. The NSCA always puts on terrific events and there will be a host of excellent speakers throughout the week. My session is scheduled for Friday, July 16, 2010.
Click here to register for the conference. Hope to see you in Orlando!
I’ve received a flood of emails recently about a recent Consumer Reports study that found various protein supplements contained potentially unsafe levels of arsenic, cadmium, mercury, and lead. The story was picked up by CBS Early Show. You can view the CBS clip for yourself here:
Before tackling the specifics of the Consumer Reports study, I feel compelled to address the spotty reporting done by CBS on the subject. First off, the hidden-camera footage of the individuals who work in supplement stores was patently disturbing. Clearly these people have no concept as to human physiology. But while this makes for good theater, should it really come as a surprise? The vast majority of supplement store workers are nothing more than low-paid clerks with no formal training in exercise or nutrition–certainly not the kind of individuals you’d want to seek out for advice on the efficacy of something you intend to put into your body. (Would you ask the secretary in your doctors office her opinion on whether or not you should take medication?).
Let’s get things straight: taking more protein than your body can utilize (generally about one gram per pound of body weight for someone who engages in intense strength training) will not result in any additional increases muscle mass. The human body cannot store excess protein for future use. Period. The moral of the story: don’t ask a store clerk for advice on supplementation–be an educated consumer and do your own research.
The CBS report also makes several unsupported claims that need clarification. For one, protein intake has not been shown to lead to dehydration. In a recent review on the subject, Martin and colleagues (2005) trace the genesis of this erroneous claim to an unsubstantiated extension of a 1954 review on nitrogen balance. Fact is, the belief has no credence. Current literature shows no evidence of dehydration associated with protein intake in healthy individuals. It’s an old-wives tale that needs to be put to rest.
Moreover, the claims that increased protein consumption heightens a person’s risk for osteoporosis are equally unsubstantiated. The overwhelming body of research shows that protein intake has no negative effects on bone loss (Spencer et al., 1988; Bonour, 2005). In fact, studies suggest that protein intake is actually positively correlated with bone mineral density of the femur, lumbar spine and distal radius (Cooper et al., 1996; Geinoz et al., 1993). I will elaborate on this subject in a future blog post but, in the meantime, read the referenced studies to form your own opinion.
Okay, let’s move on to the Consumer Reports investigation into protein supplements. According to their tests, heavy metals were present in all 15 of the protein supplements evaluated. Three products–EAS Myoplex Original Rich Dark Chocolate Shake (ready-to-drink liquid formula), Muscle Milk Vanilla Crème, and Muscle Milk Chocolate powder–were found to exceed limits established by the United States Pharmacopeia (USP) in at least one of the metals. A fourth product, Muscle Milk Nutritional Shake Chocolate (ready-drink liquid formula), was found to approach the USP daily limit for arsenic.
Now before jumping to conclusions and swearing off consumption of any protein supplement, it should be noted that, in their written findings, the Consumer Reports team states the “concentrations in most products were relatively low.” It is only “when taking into account the large serving size suggested, the number of micrograms per day for a few of the products was high compared with most others tested.” Apparently the serving size alluded to here is three per day. While I’m sure there are some who do scarf down such hefty amounts of protein supplements, it is much more common to use them as a pre- or post-workout drink in a single daily serving. Thus, the conclusions drawn in the study seem to be misleading for a majority of protein supplement consumers.
Consumer Reports also did not disclose its testing methods used in the evaluation. Although Consumer Reports is generally regarded as a reputable organization, their lack of disclosure here does not allow interested parties to scrutinize the accuracy of their findings. As someone who serves as a reviewer for several peer-reviewed journals, I can tell you that such an omission would automatically preclude publication as a scientific study. Does this nullify the results of the tests? Certainly not. But it does raise a red flag and leave open the possibility that results may be flawed.
In case you dismiss such a possibility outright, I encourage you to read the Statement Regarding Consumer Reports Article on Protein Drinks issued by NSF International, a not-for-profit, non-governmental organization and leader in product certification for public health and safety. In their statement, NSF claims that the Consumer Reports study, “…omits critical information about the laboratory that performed the test and its accreditation qualifications. ISO 17025 accreditation is critical for any laboratory testing for heavy metals in dietary supplements and nutritional products.” Interestingly, testing carried out under NSF supervision found that, “Muscle Milk Chocolate and Muscle Milk Vanilla Crème have been certified to NSF/ANSI Standard 173. The samples analyzed met the maximum acceptable limits of the standard based upon our validated test methods.” Who is right here? Who knows? But the waters surrounding the topic have been muddied. Clearly more testing is needed to bear out the facts.
Still and all, it is hard to deny that the findings of the Consumer Reports study on protein supplements are alarming in the very least. More than anything, the study highlights the fact that the industry remains virtually unregulated. Unless and until a private organization decides to investigate a product’s ingredients, supplement manufacturers are basically left on their own to comply with proper standards. What to do? Your best bet to ensure quality is to look for supplements that bear the “USP Verified” seal. This shows that a product has met the scrutiny of the USP Dietary Supplement Verification Program, where supplements are tested for quality, purity, and potency. USP verification ensures that 1) products contain the ingredients listed on the label, in the declared potency and amounts; 2) do not contain harmful levels of specified contaminants; 3) will break down and release into the body within a specified amount of time; and 4) have been made according to FDA current GMPs using sanitary and well-controlled procedures. Submission to the USP program is voluntarily, and only a handful of companies choose to comply. You might pay a little more for those who do, but considering what’s at stake, it’s worth the peace of mind.
Bonjour JP. Dietary protein: an essential nutrient for bone health. (2005). J Am Coll Nutr. 24(6 Suppl):526S-36S.
Cooper C, Atkinson EJ, Hensrud DD, et al. (1996). Dietary protein intake and bone mass in women. Calcif Tissue Int. 58:320–5.
Geinoz G, Rapin CH, Rizzoli R, et al. (1993). Relationship between bone mineral density and dietary intakes in the elderly. Osteoporos Int. 3:242–8.
Martin WF, Armstrong LE, Rodriguez NR. Dietary protein intake and renal function. Nutr Metab (Lond). 2005 Sep 20;2:25
Spencer H, Kramer L, Osis D. (1988). Do protein and phosphorus cause calcium loss? J Nutr. 118(6):657-60.
One of the biggest debates in the fitness field over the past couple of decades revolves around whether performing a single set of an exercise is as effective as performing multiple sets. This controversy took on a new dimension back in 1998 when Carpinelli and Otto published a review paper in the journal Sports Medicine siding with the single set proponents. These authors cited a lack of evidence and theoretical physiological basis showing any added benefits to performing multiple sets. If true, this would have significant implications for those who workout. After all, performing just a single set is much more time efficient than performing multiple sets–you could basically get in a workout in 1/3 time!
Unfortunately, the overwhelming body of research does not support the position of Carpinelli and Otto. Two recent review papers by James Krieger can be considered definitive evidence of the superiority of multiple sets. Using a technique called meta-analysis (where the results of many studies are combined to form a conclusion with greater statistical power), Krieger determined that multiple sets result in greater improvements in both muscle development and strength compared to single-set protocols. And we’re not talking slight differences here. Strength gains were found to be 46% greater and muscle growth 40% greater when performing multiple sets. That’s major!
Interestingly, these results held true for both trained as well as untrained subjects. This runs against conventional wisdom. It had often been believed that multiple set superiority might be limited to those with training experience. Not so. The studies by Krieger provide proof that those who are new to training also benefit from performing multiple sets.
Now this is not to say that performing single sets has no utility. Clearly, a person can get stronger and more muscular from routines that employ just one set per exercise. But it is just as clear that if you want to maximize these parameters, multiple sets are a must. This is even more important for more advanced trainees, as the body adapts to the stresses of exercises and thus greater increases in volume are necessary to elicit additional improvements in body composition and strength. Bottom line: While single set programs may suffice if you are time pressed, at least 2 to 3 sets are required per exercise for best results.
Carpinelli RN, Otto RM. Strength training. Single versus multiple sets. Sports Med. 1998 Aug;26(2):73-84.
Krieger JW. Single vs. multiple sets of resistance exercise for muscle hypertrophy: a meta-analysis. J Strength Cond Res. 2010 Apr;24(4):1150-9.
Krieger JW. Single versus multiple sets of resistance exercise: a meta-regression. J Strength Cond Res. 2009 Sep;23(6):1890-901.
Gym lore professes that altering the position of your legs while performing leg extensions can selectively target different aspects of the thighs. Evidence supporting this claim, however, is highly speculative.
Some studies have shown that turning your legs out (externally rotating them) increases stimulation of the vastus medialis (the teardrop-like muscle on the inside of your leg) and that turning your legs in (internally rotating them) shifts the emphasis to the vastus lateralis, the muscle located on the outer portion of your leg. If true, this would allow you to selectively target one quadriceps muscle over the other, providing a means to improve symmetry and correct strength imbalances in the quadriceps. Other studies, however, have shown no benefit to internal or external rotation of the legs during extensions, with the vastus lateralis and medialis receiving fairly equal work. When looking at the totality of research, the evidence of a beneficial effect is equivocal. At best, it would appear that the overall ability to target individual muscles of the quadriceps is minimal, with limited impact on strength and shape.
Now consider that employing the technique could come at a heavy cost. Even under ideal circumstances, the leg extension places a great deal of stress on the knees. Since loading is applied perpendicular to the long axis of the tibia, it creates tremendous shear force on the patellar region. What’s more, during performance, the quadriceps reacts to the movement by pulling the tibia forward (a phenomenon called tibial translation), causing the anterior cruciate ligament (ACL) to oppose the action. This can overstress the ACL, potentially injuring the ligament (and other soft tissue structures, as well).
Turning the legs in or out will only exacerbate these effects. Excessive internal or external rotation puts the patella in a position where it tracks in an unnatural way. Combined with effects of shear force and anterior tibial translation, stress to the knee capsule is heightened, significantly increasing the prospect of injury. This isn’t something to take lightly. An injury to the knee can set back your training efforts indefinitely, perhaps even requiring surgery and a lengthy rehabilitation stint.
Given the facts, I’d caution against any extreme rotation of the legs when performing leg extensions. The risk/reward ratio simply isn’t favorable. During performance, keep your toes straight or slightly angled out. This will allow optimal tracking of the patella and thus minimize injury potential. Your knees will thank you.
I will be giving a webinar on the “Facts and Fallacies of Fitness” on Wednesday, June 16 at 2 pm, EST. The webinar is being hosted by the NSCA and will debunk some of the common myths associated with exercise and nutrition in an evidence-based fashion. The webinar is open to the general public and will involve a question/answer session following the presentation. I hope you will join me for what I guarantee will be an enlightening session. You can register for the webinar by clicking on the poster below:
If you’ve ever bought a meal replacement bar, you’re probably familiar with the the term net impact carbs. Simply stated, net impact carbs refers to the amount of carbs in a product that promote an insulin response. As you may know, carbs can raise blood sugar levels, causing insulin levels to spike.
Why is this important? Well, high blood sugars levels cause the pancreas to secrete insulin in large amounts. Insulin is a storage hormone. While its primary purpose is to neutralize blood sugar, it also is responsible for converting sugars into body fat as well as inhibiting the conversion of stored fat into energy. When carbohydrates are ingested, the pancreas secretes insulin to clear blood sugar from the circulatory system. Depending on the quantities and types of carbs consumed, insulin levels can fluctuate wildly, heightening the possibility of fat storage.
To mitigate insulin response, many nutriceuticals substitute high-glycemic carbs with alternative carb-based nutrients called sugar alcohols (also called polyols), which have a negligible impact on blood sugar. Theoretically, by limiting carbohydrates that increase insulin levels (i.e. net impact carbs), you can minimize the deleterious effects of insulin and promote better weight management.
But while it’s true that carbohydrates that raise blood sugar can be detrimental to maintaining low body levels, the concept of net-impact carbs isn’t as clear cut as it may seem. Generally speaking, meal replacement bars also contain a combination of protein, fat and/or fiber. This slows digestion and moderates glycemic response, thereby reducing the fat-storing effects of insulin.
On the plus side, the sugar alcohols (such as maltitol, mannitol, sorbitol, Xylitol, and HSH) used as replacement carbs are not able to be fully absorbed by the body and thus are lower in calories than “standard” carbohydrates. They contain between two to three calories per gram as opposed to the four calories per gram in glucose, fructose and galactose (glycerol, a sugar alcohol found in many bars due to their propensity to keep foods moist and improve shelf life, also contains four calories per gram). Since calories do count and ultimately have the greatest effect on whether you gain or lose body fat, this is a benefit for those seeking to lose weight.
Bottom line: Nutrition is a complex subject and it’s important to understand that many factors come into play when designing a regimented eating plan. From an insulin standpoint, the overall effect of net impact carbs on body composition will be negligible. Significantly more important is the nutritional content and caloric density of the food source.
One of the most popular advertising gimmicks associated with supplements and various fitness equipment products is the use of before and after transformation pictures. You’ve no doubt seen them. The “before” picture will show a person slouched, looking paunchy, no muscle definition, and usually sporting a frown to accentuate how unhappy he/she is with his/her physique. Then there’s the “after” photo where the individual has evidently transformed himself/herself into a lean, toned god/goddess, with a big smile to match how happy they are with their new body. The images are powerful. They’re enticing. They make you want to pick up the phone and order the product. Unfortunately, they are all-too-often scams. The “after” shots are augmented by shaving, spray-tanning, proper postural alignment and a healthy dose of Photoshop. Sometimes the photos are even taken on the same day, within mere minutes of each other!
Check out the video clip from the movie, Bigger, Stronger, Faster (which. if you haven’t yet seen it, is a really good movie, BTW) that exposes how many of these so-called “transformations” are done. It’s an enlightening video that should make you think twice before plunking down your hard-earned money for that magic supplement or fitness gizmo.