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Why is Protein a Diet Essential For Muscle Growth and Bodybuilding?

Director Cardiology, Fortis Escorts Hospital
Jan 20, 2019 5:07 AM 6 min read

Proteins are well known as the building blocks of muscle. They are made up of amino acids, which are divided into Essential and Non-essential. Non-essential does not suggest unimportant. Its rather a medical term implying they can be synthesised in the body, while the Essential ones can’t.

Hence, Essential amino acids must be consumed as part of one’s diet, as their deficiency hinders effective muscle growth. 

Further, proteins have the same calorie content as carbs (about 4kcal/g) but are much harder to digest. Nearly a third of their calories are consumed merely in digesting them. This means consuming proteins keeps us full for longer, and imposes a lighter calorie burden on the system, resulting in weight loss and muscle building, if supported by proper exercise.


Yes, muscle growth is a function of two inputs - proper nutrition AND exercise, both alone being inadequate for the best results.


Speaking of the nutrition part...for years debates have raged around two aspects:

1. How much protein is required daily, for building muscle?

2. Are meats the only good source of protein?

How Much Protein?

The first question is harder to answer than commonly believed. The Recommended Dietary Allowance (RDA) say that for a normal, healthy adult (read sedentary individual), about 0.8-1 g/kg of body weight is enough. This translates to around 56 g/day for an adult male weighing 70 kg and 46 g/day for a 59 kg female. Even this amount is hard to source in average Indian vegetarian diets.

Why is Protein a Diet Essential For Muscle Growth and Bodybuilding?


Moreover, much higher intakes are recommended for inducing optimal muscle growth.

For those who practice regular strength training, the requirement stands at around 1.5-2 g/kg of body weight. These are recommended for professionals and not the average gym enthusiast, who could do well with c.1 g/kg, with a reasonable upper limit of 1-1.5 g/kg daily.

Bodybuilders supposedly need even higher intakes, with different authorities recommending 1-1.5 or even upto 2 g/lb body weight (1 kg=2.2 lb), meaning an intake of upto 2.2-4.4 g/kg body weight. This kind of consumption is obviously impractical, except for professional athletes, who typically consume 4,000-6,000 kcals per day via 6-7 divided meals. Note: This is NOT recommended for weekend enthusiasts and needs professional advice - which this series of articles does NOT claim to be. Consult your Dietician.

The very idea of heavy protein intake for muscle building has been questioned. Coach Wade, the author of Convict Conditioning, rightly questions this guideline - having witnessed convicts achieve massive gains in strength and muscularity, despite being on relatively restricted prison diets, and being limited to bodyweight exercises and few fixed weights.

Having said that, a healthy protein intake along with willpower certainly helps build muscle and prevent muscle breakdown, especially while trying to lose fat in order to achieve definition.

The Best Sources of Protein

Now to the second question. The best source of protein comprise: eggs, meats (red and white), fish, milk and nuts. These deliver the most healthy and complete proteins having all Essential amino acids.

Also, as you can notice, these are largely non-vegetarian sources. Does that mean that vegetarians can't have enough protein or become strong?


Why is Protein a Diet Essential For Muscle Growth and Bodybuilding?


Absolutely not! But non-vegetarian foods definitely have their advantages with respect to muscle building. For starters, they contain complete proteins with all the Essential amino acids. They also have a much greater protein content per gram, containing 50-90% of their calorie content as protein, compared to 13-20% of total calories in vegetarian sources.

Conversely, most vegetarian sources lack a few of the Essential amino acids. The only vegetarian source of complete protein is: soy, buckwheat and quinoa. Other healthy vegetarian sources are nuts (almonds, walnuts, cashews, pistachios, pecans, peanuts), tofu and tempeh (from soybeans), lentils (daals), chickpeas and beans like kidney and black beans (also called legumes), green peas, spirulina, oats, wild rice, chia seeds, nut butters, and vegetables like broccoli, spinach and asparagus. Fruits contain only small amounts, the maximum being found in guavas, berries and bananas.


Why is Protein a Diet Essential For Muscle Growth and Bodybuilding?


Its not practical to eat only quinoa or soy all day long, one has to improvise. For instance, daal and rice both have incomplete proteins, but daal-chawal together have all the Essential amino acids. For reassurance, some of the most impressively muscled Bollywood stars – John Abraham, Vidyut Jamwal, Sonu Sood and Shahid Kapoor are vegetarians. Around the time he was shooting for Dangal, Aamir Khan became a vegan as well.

Further, in India there are 3 types of vegetarians – vegans, lacto-vegetarians (a diet that includes vegetables as well as dairy products) and ovolacto-vegetarians (a vegetarian who does not eat meat, but does consume some animal-derived products such as eggs and dairy).

Obviously, it is much easier for the latter two groups to imbibe the required amount and quality of proteins - eggs and milk/dairy are some of the richest and best sources.

Eggs contain very high quality proteins. The PDCAAS score (a marker of protein quality) is 1 for egg protein and whey. One large egg has about 6.3 g proteins, about 3.75 g being in the white. Soya is another excellent source of proteins. Notably, it also contains phyto-oestrogens, making it unsuitable for consumption in substantial amounts by males.

Milk also has IGF-1 (Insulin like growth factor-1), which is also very helpful in bulking up. So, next time someone says she is a hard-gainer, tell her to drink two glasses of whole milk daily and exercise: she will be surprised. 

Protein Supplements

Anybody aiming for >1-1.5 g/kg daily intake of proteins has to take supplements. They broadly come from 3 sources - whey and casein derived from milk; albumin from egg whites; and soya. Whey and casein can be consumed by lactovegetarians. The former is better for muscle building (more anabolic), while casein is slowly digested and so is better for preventing muscle breakdown (anti-catabolic).

 Why is Protein a Diet Essential For Muscle Growth and Bodybuilding?


A lot of controversy exists about the role of protein supplements. Proteins are digested by the kidneys, hence there is no problem with consumption of reasonable amounts of proteins (1-1.5 g/kg body weight) if kidney function is normal. However, when professional bodybuilders take huge amounts of proteins (2-4.4 g/kg) along with drugs/supplements of questionable quality (as proteins are very expensive), chances of damaging the liver and kidney are high.

Thus, one should preferably consume natural foods rich in proteins rather than large amounts of whey or other supplements; if one has to, then 30-40 g of whey or other supplement protein is a reasonable amount per day.

In summary, proteins are very important for building muscle. A healthy consumption is even more important for strength trainees. While meats, eggs and dairy are the best sources of complete proteins, it’s quite possible to consume healthy proteins as a vegetarian (even as a vegan), and become strong and muscular.

Next week, we shall try Understanding The Myth Behind Converting Fat into Muscle.

This is a recurring column published every Sunday under the title: What is Nutrition.

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