With all the diet trends athletes try in an attempt to get faster and stronger, the most popular questions surround protein. In athletics, protein is held to an almost sacred standard for skeletal-muscle tissue repair. This post is an attempt to clarify some of the questions surrounding protein.
The seven points relate to the intake of protein for healthy exercising individuals and are as follows (Campbell et al., 2007):
1. Individuals engaged in regular exercise training require more dietary protein than sedentary individuals.
2. Protein intakes of 1.4–2.0 g/kg/day for physically active individuals is not only safe but may improve the training adaptations to exercise.
3. When part of a balanced, nutrient-dense diet, protein intake at this level (1.4-2.0 g/kg/day) is not detrimental to kidney function or bone metabolism in healthy, active persons.
4. While it is possible for physically active individuals to obtain their daily protein requirements through a varied, regular diet, supplemental protein in various forms is a practical way of ensuring adequate and quality protein intake for athletes.
5. Different types and quality protein can influence amino-acid bioavailability following protein supplementation. The superiority of one protein type over another in terms of optimizing recovery and/or training adaptations remains to be convincingly demonstrated.
6. Appropriately timed protein intake is an important component of an overall exercise-training program, essential for proper recovery, immune function, and the growth and maintenance of lean body mass.
7. Under certain circumstances, specific amino-acid supplements, such as branched-chain amino acids (BCAAs), may improve exercise performance and recovery from exercise.
These basic recommendations set in place by the International Society of Sports Nutrition give registered dietitians, nutritionist, coaches, and athletes fundamental suggestions to follow.
The International Society of Sports Nutrition summarized their findings into the following eight principles:
1. consuming a mix of carbohydrates and protein before a workout maximally stimulates protein synthesis.
2. Ingesting a mix of carbohydrates and protein every 10-15 minutes during exercise maintains protein synthesis.
3. Ingesting carbohydrates alone or in combination with protein during resistance exercise increases muscle glycogen, offsets muscle damage, and facilitates greater training adaptations after supplementation with resistance training.
4. Post-exercise (within thirty minutes) consumption of carbohydrates at high dosages (8–10 g CHO/kg/day) have been shown to stimulate muscle glycogen resynthesis, while adding protein (0.2 g–0.5 g PRO/kg/day) to carbohydrates at a ratio of 3–4:1 (CHO: PRO) may further enhance glycogen resynthesis.
5. Post-exercise protein consumption also increases muscle protein synthesis, while the addition of carbohydrates may stimulate even greater levels of protein synthesis.
6. During consistent, prolonged resistance training, post-exercise consumption of varying doses of carbohydrate and protein supplements in varying dosages have shown to stimulate improvements in strength and body composition when compared to control or placebo conditions.
7. The addition of creatine (Cr) (0.1 g Cr/kg/day) to a carbohydrate and protein supplement may facilitate even greater adaptations to resistance training.
8. Nutrient timing incorporates the use of methodical planning and eating of whole foods, nutrients extracted from food, and other sources. The timing of the energy intake and the ratio of certain ingested macronutrients are likely the attributes, which allow for enhanced recovery and tissue repair following high-volume exercise, augmented muscle protein synthesis, and improved mood states when compared with unplanned or traditional strategies of nutrient intake. Providing evidence that a combination of protein and carbohydrates prior, during, and after exercise will provide the best results in performance and recovery. These findings are applicable to every athlete’s training regimen seeing that all athletes must take full advantage of their diet including effective timing if they want to attain the most gains possible.
A study by Hoffman et al. (2006) wanted to determine if excessive protein consumption helped athletes. Findings showed no differences in energy intake between the groups. Moreover, energy intake for all groups was also below the recommended levels for strength/power athletes.
Results of the study showed no significant changes in body mass, lean body mass, or fat mass in any group. Significant improvements in 1RM bench press and 1RM squat were seen in all three groups; however, no differences between the groups were observed. Subjects in the above recommended levels group experienced a 22 percent and 42 percent greater change in 1RM squat and 1RM bench press than subjects in the recommended levels group; however, these differences were not significant. No significant changes were seen in any of the resting hormonal concentrations.
These findings suggest ingesting protein beyond recommended levels in collegiate strength/power athletes for body-composition improvements or alterations in resting hormonal concentrations will not show any further improvements than taking recommended dosage. With all the high-protein supplements on the market, these findings suggest the benefits of ingesting protein beyond recommended levels may be minimal at best, and athletes may have better results investing their resources in other safe supplementation methods and stacking (combining) protein with creatine or carbohydrates. It is also known that when too great a focus is placed on protein, athletes may miss out on other free-testosterone promoting nutrients such as boron and magnesium. For this reason, excessive protein should not be consumed, but rather a well-balanced diet with adequate protein intake is suggested for muscle growth.
Keep Whey Protein Consumption Under 20g/Serving and Casein Under 40g/Serving
Milk Consumption Helps Meet Your Protein Needs
A study by Roy (2008) investigates the new growing interest in bovine milk to see if there is justification in its growing popularity as a sports drink substitute, especially as a recovery agent after exercise. Roy examined the limited research and concluded that milk appears to be an effective post-resistance exercise beverage resulting in desirable acute alterations increasing muscle protein synthesis, leading to an improved net muscle-protein balance. What’s more, when post-exercise milk consumption is combined with resistance training (twelve weeks minimum), greater increases in muscle hypertrophy and lean mass have been observed. Although research with milk is limited, there is some evidence to suggest that milk may be an effective post-exercise beverage for activities.
Additionally, low-fat milk has been shown to be as effective, if not more effective, than commercially available sports drinks as a rehydration beverage. For athletes in need of a more nutrient-dense beverage choice, milk represents a great alternative for those who partake in strength and endurance activities, compared to traditional sports drinks. Bovine low-fat fluid milk is a safe and effective post-exercise beverage for most individuals, except for those who are lactose intolerant. Roy notes further research is needed to better set forth the possible applications and efficacy of bovine milk in the field of sports nutrition. Roy’s research is an appropriate example of how everyday foods and beverages can give athletes the same if not better results than sports supplements developed in labs and engineered by scientist. These results provide proof that natural foods should be the foundation of a healthy diet and supplements should be just that, supplementing a natural diet.
Recovery Drinks with a 3-4:1 Carb-to-Protein Ratio Are Best for a Quick Recovery
High Protein Diets Aid in Weight Loss
While many sports focus on getting athletes as big and strong as possible, an equally large number of sports are hard pressed toward maintaining a low body-fat percentage and high strength-to-weight ratio. With respect to diets and weight loss, there is a decades old debate regarding which macronutrient restricted diet will promote the most weight loss. Recent research by Noakes, Keogh, Fosters, and Clifton (2005) shows that when on an energy-restricted diet high in protein and low in fat, the nutritional and metabolic benefits are equal and sometimes greater than those observed with a high carbohydrate diet.
Additional findings to support a high-protein diet were uncovered by Lockwood, Moon, Tobkin, Walter, Smith, Dalbo, Cramer, and Stout (2008) shows that when on a non-calorie-restricted diet consisting of high-protein, low-fat, and low-carbohydrate, overall nutrition intake improved, physiological adaptions to exercise increased, and muscle mass and time-to-exhaustion enhanced. Moreover, it was shown by Ivy, Res, Sprague, and Widzer (2003) that protein and carbohydrate supplementation increased endurance in athletes more than carbohydrate supplementation alone. However, the reason for the finding is unknown. With that said, athlete’s desiring to reduce body fat in a safe manner while maintaining lean mass should use a high-protein, low-fat, and low-carbohydrate diet. Keeping in mind, excessive protein intake can also hinder progress and should, therefore, be consumed within recommended ranges.
Protein is More Metabolically Active than Other Macronutrients
With all this research revealing high-protein diets as an effective diet model for athletes looking to gain or maintain lean mass while increasing performance, the question, “why is protein so metabolically effective at building athletes?” comes to mind. Answers to why high-protein diets are effective at reducing body fat while maintaining lean mass in a safe manner may reside in a study titled “A Calorie Is a Calorie,” by Feinman and Fine (2004). Feinman and Fine state the manner people view calories as all being created equal with respect to usable energy violates the second law of thermodynamics. It was pointed out that a calorie is not a calorie as far as the three macronutrients providing equal amounts of energy per calorie is concerned.
Researchers pointed out the second law of thermodynamics, something is lost and, therefore, balance is not to be expected, does not account for living things. The thermic effects of food (energy being used to breakdown the macronutrients into usable energy) is not equal. Fat uses 2–3 percent, carbohydrates 6–8 percent, and proteins 25–30 percent of their energy in the process of becoming usable energy for the body. Therefore, protein’s high energy demands to be metabolized by the body naturally make it a less caloric energy substrate because of its own chemical makeup. This is partially due to protein containing nitrogen, which makes it harder to metabolize. The nitrogen in protein is also why high-protein dieters lose more initial weight than high-fat dieters, the nitrogen uses more water to metabolize and thus high-protein dieters can attribute most of their initial weight loss to water loss.
Proteins Use 25-30 Percent of Their Own Energy During Digestion
High Protein or High Fat Diet?
On the other side of the coin, despite all the research supporting high-protein diets, Luscombe-Marsh, Noakes, Wittert, Keogh, Foster, and Clifton (2005) has shown slightly different results. Revealing in addition to high-protein diets promoting weight loss, high-fat diets have been shown equally effective at promoting fat loss and improving blood lipids. It is my opinion that this is a result of higher free-testosterone from a wider range of nutrient intake when focusing on high-fat diets. As well as many high-protein diets generally revolving around higher fat foods.
Lemon (1991) gives a review of protein needs of strength athletes. Lemon highlights evidence indicating that actual protein requirements of strength athletes are higher than those of more sedentary individuals. Data also suggests the combination of high-protein/amino-acid diets combined with heavy resistance exercise training can enhance the development of muscle mass and strength. It is also of note novices may have higher needs than experienced strength athletes, and substantial individual variability exists. Furthermore, Norton and Layman (2006) showed the branched-chain amino acid leucine is necessary for protein synthesis in skeletal muscle after exercise. These findings suggest that, although inconclusive, high-protein/amino-acid diets specifically containing leucine among strength athletes may be beneficial in producing lean mass and strength.
Leucine Aids in Building Lean Muscle Mass and Strength
Eggs are Safe...for Now
With all the research showing high-protein diets as an effective diet for athletes, it is important to point out chicken eggs, which are a standard in many high-protein diets were shown to be safe with respects to heart disease. Research conducted by Donald J. McNamara (2000) showed when an egg is consumed, it introduces a 100 mg change in dietary cholesterol and a 2.2 mg/dL change in plasma total cholesterol. Although these changes may seem significant, it is not the change in plasma total cholesterol that increases risk of heart disease but the ratio of low density lipoproteins (LDL) to high density lipoproteins (HDL), LDL:HDL, indicating heart disease. Furthermore, consuming an egg produces minimal changes in the LDL:HDL ratio, thus consuming an egg does not increase the risk of heart disease.
Eating Eggs Does Not Lead to Heart Disease
Protein and Aging
Additionally, it was discovered by Symons, Schutzler, Cocke, Chinkes, Wolfe, and Paddon-Jones (2007) in their research on the effects of aging on the body’s anabolic response to a protein-rich meal; although differences in the concentration of amino acids in the plasma-precursor pool where noticed, aging does not impair muscle protein synthesis after eating a protein-rich food.
Aging Does Not Diminish Muscle Protein Synthesis
With a vast pool of research supporting high-protein diets, it is worth time examining potential damaging effects on the body by consuming a high-protein diet for a long term. Poortmans and Dellalieux (2000) investigated body builders and other well-trained athletes with high- and medium-protein intake, respectively, to shed light on excess protein and amino-acid intake and kidney function, leading to progressive kidney impairment. Participants underwent a seven-day nutrition record analysis as well as blood sample and urine collection to determine the potential renal consequences of high-protein intake. The data revealed that despite higher plasma concentration of uric acid and calcium, the group of body builders had renal clearances of creatinine, urea, and albumin that were within the normal range. The nitrogen balance for both groups became positive when daily protein intake exceeded 1.26 g/kg, but there were no correlations between protein intake and creatinine clearance, albumin excretion rate, and calcium excretion rate. Findings suggest that protein intake under 2.8 g/kg does not impair renal function in well-trained athletes as indicated by blood sample and urine collection.
Periods of Protein Intake Up To 2.8g/kg are Safe for Healthy Individuals
Martin, Armstrong, and Rodriquez (2005) also provide a review on increased dietary protein intake as a health concern in terms of the potential to initiate or promote renal disease. Martin and colleagues conclude, while protein restriction may be appropriate for treatment of existing kidney disease, there is no significant evidence for a detrimental effect of high-protein intake on kidney function in healthy persons after centuries of a high-protein Western diet. With that said, healthy athletes may continue to consume high-protein diets unless their body’s renal function tells them otherwise, in which they should seek medical attention.
In closing, moderate to high levels of protein appear to be an essential and healthy component in an athlete’s diet. Supplementing protein with carbohydrates, creatine, and branched-chain amino acids increases the anabolic effects of protein further than protein ingestion alone. Although protein is an effective agent for physiological change in athlete composition and performance, it is worthy of note that a proper training regimen must but utilized with proper nutrition to trigger the endocrine responses and physiological changes possible through proper sports nutrition. Further reading should be done regarding the body’s response to protein under additional circumstances such as first thing upon waking up, prior to bed, protein’s effect on concentration, and gender differences concerning protein consumption. As a popular macronutrient, extensive research has been done on protein that is beyond the scope of this book.
*Did you know Chris has a sport and exercise book available on Amazon loaded with more science based recommendation on how to maximize your athletic potential?!