Bodybuilding Nutrition - Six Scientific Facts

1) Protein Quality Important for Muscle Growth

Dietary proteins provide amino acids that form the building blocks of protein synthesis. Key amino acids such as leucine also act as triggers for muscle protein synthesis. A review of literature by Stuart Phillips from McMaster University in Canada concluded that protein quality was an important consideration for maximizing muscle protein synthesis in weight-training athletes. High-quality proteins contain large amounts of key amino acids such as leucine that are easily digested. Protein quality is an important consideration in sports nutrition programs designed to build strength, power and alter body composition. (Nutrition & Metabolism, 13:64, 2016)

2) The Downside of Overconsumption of Nitrates

Beetroot juice improves endurance, promotes blood flow and reduces blood pressure. Many recent studies show that it is a heart-healthy food. Beetroot is high in nitrate, which is converted to nitric oxide— an important chemical secreted mainly by the inner lining of the blood vessels that control blood flow. While it protects against heart attack, enlarged heart and heart failure, there might be a downside from overconsumption of nitrates. A review of literature by Ryszard Pluta, a retired scientist from the Surgical Neurology Branch of the National Institute of Health, concluded that excessive nitrate consumption might trigger inflammation, liver damage and certain cancers. Beetroot juice has positive effects on blood pressure, muscle metabolism and blood flow, but we need more information on the health risks of overconsumption of nitrates from the diet and nitrate supplements. Vegetable sources of nitrates such as beetroot and spinach are preferable because they are a rich source of antioxidants such as vitamin C, carotenoids, phenolic acids, flavonoids and betalains. (Reviews on Recent Clinical Trials, 11: 135-140, 2016)

3) Salmon Consumption Reduces Heart Attack Risk

Consuming farmed Atlantic salmon twice a week improves the blood fat profile in overweight men and women— according to a study led by Susan Raatz from the University of Minnesota. The benefits were dose-dependent— eating more fish triggered greater benefits in blood fats. The study found that salmon consumption reduced blood triglyceride (blood fat) and increased HDL cholesterol levels (the good cholesterol). It also benefited the size of lipoprotein molecules, which is important for reducing the risk of coronary artery disease. Regular salmon consumption is part of a heart-healthy diet. (Nutrition Research, 39:899-906, 2016)

4) Protein Effects on Muscle Hypertrophy Not Affected by Muscle Size

High protein intake promotes muscle hypertrophy, but the amount of growth is not affected by initial muscle size— according to a study led by Lindsay Macnaughton and Kevin Tipton from the University of Stirling in Scotland. Test subjects performed a weight-training workout and were given a supplement containing either 20 or 40 grams of protein. Higher protein intake resulted in greater protein synthesis, but the results were not influenced by muscle size. The research yields two important take-home messages, the first being that athletes with greater muscle mass do not need more protein to promote muscle growth. Additionally, a protein supplement containing 20 or 40 grams of protein has the same effect on muscle protein synthesis in people with smaller or larger muscles. (Physiological Reports, 4 (15): e12893, 2016)

5) Protein Supplements Do Not Alter Anabolic Hormone Responses After Training

Consuming a supplement containing 20 grams of protein, six grams of carbohydrates and one gram of fat following a weight-training session had no effect on the hormones insulin-like growth factor 1 (IGF-1), insulin, testosterone, growth hormone or cortisol— according to a study led by Adam Gonzales from Hofstra University in New York. Protein supplements containing the amino acid leucine activate the mTOR pathway of muscle protein synthesis. Weight training triggered similar increases in insulin, growth hormone and cortisol in athletes consuming a protein supplement or a placebo (fake protein supplement). Protein supplements and hormones have different effects on muscle protein synthesis. (Nutrition Research, 35:990-1000, 2015)

6) Paleo Diet: Gift From Our Ancestors, or Bunk?

The Paleolithic or caveman diet is based on consuming berries, nuts, lean grass-fed meats and fish— according to a literature review by Katherine Beals from the University of Utah. The rules of the Paleo diet are simple: if you can pick it, grow it or kill it, then you can eat it! Proponents of the diet claim that human genes evolved over thousands of years to optimize metabolism from eating these natural foods. Industrialization changed the human diet suddenly, to include the consumption of grains and calorie-dense, high-fat, processed foods. Food choices also increased dramatically, which promoted overeating and overconsumption of unhealthy foods. Several studies found that the diet reduces abdominal fat, abnormal blood fats, blood pressure, insulin resistance and type 2 diabetes. Critics of the diet point out that the diets of ancient humans varied greatly from one place to another, so that it is unlikely that metabolically linked genes adapted uniformly. Also, Paleo diet studies are plagued by poor research designs, inadequate dietary controls and poor compliance by the test subjects. We need more research before we can recommend this diet to serious athletes. (ACSM’s Health & Fitness Journal, 20(6): 18-25, 2016)

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