The area of interest that I will look into for designing a research proposal will be how diet and dietary supplements effect muscle growth. I have some experience in trying to increase muscle growth through weight training, and personally believe that there are numerous, influential factors which can affect your training goals. There are many variables to think about when wanting to increase muscle mass or size. These variables could be taken into consideration for pre-training, during training and also post-training. I believe one of the key elements you need to focus on when trying to gain muscle growth is diet; which can be a very vast and complicated topic.
There can be many different suggested strategies of dieting and supplementing which can be implemented on achieving your specific goal. Therefore the different types of food and food supplements you consume can have a key influence on whether it aids your training programme and goals, or hinders it. Thalacker (2009) explains that weight training makes you stronger and bigger. However, the result you get from training might vary dramatically from the result of your training partner who is doing the exact same training program.
The reasons for these variations might relate to both intrinsic factors such as your genetics and extrinsic factors like your diet. While you do not have any control over your genetics, you can control your diet. However, scientists do not clearly understand exactly how diet can affect changes in your muscle size. For example, protein intake is one variable that might affect your training response. While some studies support greater muscle gains with greater protein intakes, others do not. Nonetheless, the commercial sector took advantage of a gap in the market and is now producing diet supplements that claim to aid a range of peoples training goals, including muscle growth.
Thalacker (2009) presents results that researchers from the University of Alabama recently published of a cluster analysis, looking at the effects of dietary variables on muscle growth. The study recruited 35 untrained men and 31 untrained women to take part in a 16 week training programme. The study showed that the average body weight of the subjects did not change over the 16 weeks, indicating that the subjects were consuming just enough calories to maintain their weight.
The study showed that there was no association between the magnitude of muscle fibre growth and any dietary intake component. Protein intake, on average, exceeded the recommended dietary allowance (RDA) of 0.36 grams per pound of body weight. The results showed that low protein intake did not necessarily translate to less muscle gain. However, this study cannot address the effect of nutrient timing; evidence indicates that consuming protein and carbohydrate soon after a training session can enhance size and strength gains. Cribb, P.J., and A. Hayes. (2006, p.1918-1925)
Clark (2006, p.40-41) presents an interview with sports nutritionist and author Nancy Clark. The main points made in the interview included what sorts and at what times should supplements be consumed to gain the most benefits. When asked what food bodybuilders should eat before they lift weights, Nancy Clark recommends eating carbohydrates before exercise and a carbohydrate-protein combination should be eaten right after a workout.
To build muscle, she recommends that bodybuilders should consume about one gram of protein per pound of body weight per day for optimal muscle development when lifting weights. She comments that whey protein is digested and absorbed into the bloodstream faster than other proteins like casein. Clark (2006) explains that whey is a rich source of the branched-chain amino acids (BCAAs) leucine, isoleucine and valine. BCAAs are taken up directly by the muscles instead of having to be metabolized by the liver first. Hence, whey is fast acting and a fairly efficient muscle energy source during exercise; plus a good source of raw materials for building muscle after exercise.
Walker (2010, p.409-417) also provides information on whey protein; he investigates the ability of whey protein and leucine supplementation to enhance physical and cognitive performance and body composition. Thirty moderately fit participants completed a modified Air Force fitness test, a computer-based cognition test, and a dual-energy X-ray-absorptiometry scan for body composition before and after supplementing their daily diet for 8 wk with either 19.7 g of whey protein and 6.2 g leucine (WPL) or a calorie-equivalent placebo (P). The study showed that bench-press performance increased significantly from Week 1 to Week 8 in the WPL group, whereas the increase in the P group was not significant.
Push-up performance increased significantly for WPL, and P showed a no significant increase. Total mass, fat-free mass and lean body mass all increased significantly in the WPL group but showed no change in the P group. No differences were observed within or between groups for crunches, chin-ups, 3-mile-run time, or cognition. In conclusion, the judgements that the authors seem to hold reflect the results of the study as Walker (2010) concludes that supplementing with whey protein and leucine may provide an advantage to people whose performance benefits from increased upper body strength and/or lean body mass.
One of the dietary supplements that Walker (2010) conducted a study on was leucine. Berg (2002, p. 126;128-129) also writes about leucine, mentioning; according to Eric Noreen, M.S., a doctoral candidate in the exercise nutrition research laboratory at the University of Western Ontario, Canada, some strong evidence suggests that branch-chained amino acids, specifically leucine, have the potential to be anabolic.
Berg (2002) goes on to mention that several recent studies have shown that taking leucine after a workout significantly raises protein-synthesis rates (muscle growth). However, for the conclusion, Noreen explains that the studies done thus far have been very narrowly focused on special circumstances and populations, which means the data can only be extrapolated to the recreational-athlete population. Berg (2002) explains that unfortunately, we really don’t know what the real-world significance is. He then goes on to state that while speculating that the increased protein-synthesis rates will mean more muscle gains over time is reasonable, that conclusion hasn’t been definitively established yet.