Protein: The Quintessential Nutrient

By Dr. Sadhna Sharma

Protein is an essential macronutrient for humans. They are required for growth and maintenance. They are the fundamental building blocks of muscles, bone, cartilage, skin, hair, and cellular components. Proteins are needed to help muscles contract and relax, and help repair damaged tissues. They play a critical role in many body functions as enzymes, hormones, and antibodies. Proteins may also be used as an energy source by the body and gives 4Kcal/g.

The demand for proteins is increasing as more and more consumers are accepting it as essential part of their regular intake, due to its important role in a healthy diet. Also rising incomes are contributing towards the increased demand for protein, since consumers prefer diet of expensive foods, such as meat, seafood and plant-based protein, such as nuts. With rapid urbanisation and fast-growing middle classes in developing countries, suddenly the world’s protein demand has reached critical levels. As we have been observing over the past years consumers have a growing appetite for all things protein. In fact people say high protein is now an important attribute to consider when buying food for their households. While the popularity of plant-based proteins is certainly growing, data shows that consumers are still choosing traditional sources of protein such as meat, eggs and dairy as their primary source. The DRI (Dietary Reference Intake) is 0.8 grams of protein per kilogram of body weight. This amounts to 56 grams per day for the average sedentary man and 46 grams per day for the average sedentary woman.

According to a recent IMRD report, 84% of the Indian consuming vegetarian foods are deficient in protein, while the number reduces to 65% for the non vegetarians. This is due to the fact that 93% of the Indian are unaware about their ideal protein requirements. The scenario is really unnerving when we look at the consequences it is creating in the life of people leading to impaired muscle function, fatigue and poor metabolic health. More so because the people do not consider this a serious health condition and it is often ignored. It is time we address this problem and take initiative to overcome this grave situation and have a better lifestyle. On the backdrop of this alarming data, IDA (Indian Dietician Association) have taken initiative to encourage people to increase their protein intake everyday and educate them about the importance of adequate protein in their body. The overarching objective is to deliver safe, nutritious and affordable protein sources, which will be imperative if the world is to withstand increased protein demand.

Animal Sources

Animal products such as meat, fish, eggs, and milk are naturally high quality protein containing all the essential amino acids which cannot be synthesized by our body. This makes it easier for people who consume animal products to meet their daily protein needs.

Eggs, Meat and Fish 

These are complete proteins as they contain all of the essential amino acids in one protein source that can be easily used by the body. Eggs provide about 13grams (g) of protein in 100g whereas chicken gives approximately 18.3 g in 100g body weight. Lean beef and pork are rich in protein providing about 36 and 30g in 100g of product. Although Tuna/Salmon provide 26g of protein /100g weight but are much healthier option because of their low fat content. 


India is a major producer of milk and milk based products such as butter, cheese, curd etc. Indians traditionally believe milk as a major constituent of their regular diet, which provides complete nutrition for a healthy body. Milk products also contain high quality proteins such as yogurt which has 6 g in 100g product and cheese with about 32 g in 100g. Casein, a protein found only in milk, contains all of the essential amino acids. It accounts for 82 percent of the total proteins in milk and is used as a standard for evaluating protein of other foods. The whey proteins constitute about 18 percent of the protein content of milk. Both are high-quality proteins, according to science-based rating scales, and both contain all essential amino acids in amounts sufficient to support the multiple roles of protein in the body. Both casein and whey proteins are present in milk, yogurt, and ice cream. In most cheeses the casein is coagulated to form the curd, and the whey is drained leaving only a small amount of whey proteins in the cheese. Whey is the simplest form of protein that contains essential amino acids and gets absorbed very easily balancing the protein requirement of the body. Not only that, it increases the strength, helps to gain muscles and lose significant body fats and clears skin. Whey proteins are used as a protein source in high protein beverages and energy bars targeted to athletes and bodybuilders. Some other uses of whey proteins are as binder to retain water in meat and sausage products, to provide a brown crust in bakery products, and to provide whipping properties that replace a portion of egg whites.

According to the United Nations Food and Agriculture Organization, the demand for food will rise by 70 per cent by 2050. Interestingly, the demand for animal proteins is rising even faster than this. Increased demand for animal proteins means more meat products are being introduced to in the market. It is though good news for the meat industry, but not so for the environment. The challenge is that increased demand of meat puts greater cost on each unit produced. This means greater losses if food does not make it to consumption. Food waste can be caused by improper handling, packaging and distribution. However, today more people are shifting to vegetarian or vegan diets or reducing their use of animal products. A shift away from animal products is getting easier with more fortified and nutritious plant-based foods available. Even so, getting enough protein and essential vitamins and minerals can be harder for people who do not eat meat or animal products. The right plant-based foods can be excellent sources of protein and other nutrients, often with fewer calories than animal products. Vegetarian or vegan diet can lower the risk of some diseases, such as certain forms of heart disease and cancer, and may promote weight loss. A diet free of animal products requires planning and research to ensure a person's nutritional needs are met. For some, this is a benefit, as it encourages them to think about their diet and understand the nutritional content of the foods they eat. For others, it can prove challenging and lead to nutritional deficits. Even producers of meat products are homing in on the trend. Tyson Foods Inc., the largest meat company in the United States, is investing in the development of plant-based meat. Addressing protein shortages will also rely on a focus on the animal feed industry. This follows recognition that more than half of all the plant-based protein produced on Earth is eaten by cattle, pigs, sheep and poultry. Providing more sustainable animal feed could free up more plant-based protein for human consumption.

Plant Source

Plant or vegetable proteins are not of the same quality as animal proteins because of their low content of some of the essential amino acids. However, a combination of cereals, millets and pulses provides most of the amino acids, which complement each other to provide better quality proteins. People who prefer vegetarian food should eat a varied diet of plant-based foods to get the required range of amino acids. This includes high-protein foods, such as tofu, tempeh, lentils, nuts, seeds, and quinoa.
Among the plant foods soybean is the richest source of protein, containing over 40% of protein. Soy beans and quinoa contain all nine essential amino acids that humans need.

Soy Products

Soy products such as tofu, tempeh, and edamame are among the richest sources of protein in a vegan diet and can be used in place of meat. They are all delicious and can be used in a variety of ways. The protein content varies with how the soy is prepared:

  • Firm Tofu (soybean curds) 
  • Edamame Beans (Immature Soybeans) 
  • Tempeh 

Tempeh is Indonesian staple, made by fermenting soybeans in banana leaves until a firm, earthy patty forms. It has been a common meat substitute since around the 12th century. Tempeh contains more protein (31 grams per cup!) and dietary fiber than tofu, and its mild nutty flavor works great in a wide array of recipes. Tofu takes on the flavor of the dish it is prepared in so that it can be a versatile addition to a meal. People can try tofu, as a meat substitute. 

These soy products also contain good levels of calcium and iron, which makes them healthy substitutes for dairy products.


Also known as wheat gluten or wheat meat, seitan first appeared during the sixth century as an ingredient in Asian cuisine and has been a common meat substitute for more than a thousand years. Traditionally, seitan was the product of rinsing and cooking wheat dough to remove the starch, leaving a protein-dense substance that turned out to be an excellent meat alternative. Since it has high wheat content, should be avoided by people with celiac disease or gluten intolerance.

Lentils & Grains 

Red or green lentils contain plenty of protein, fiber, and key nutrients, including iron and potassium. Cooked lentils contain 8.84 g of protein per ½ cup. Lentils are a great source of protein to add to a lunch or dinner routine. They can be added to stews, curries, salads, or rice to give an extra portion of protein.

Wheat and rice has about 7% protein content whereas cereals and millets provide about 10% protein. ‘Oatmeal’ has three times the protein of brown rice with less starch and more fiber. It’s also a great source of magnesium, calcium, and B vitamins. ‘Quinoa’ is a grain with high protein content, and is a complete protein. Cooked quinoa contains 8 g of protein per cup. This grain is also rich in other nutrients, including magnesium, iron, fiber, and manganese. It is also highly versatile. 

Peas & Beans 

Cooked chickpeas are high in protein, containing around 7.25 g per ½ cup. Chickpeas can be eaten hot or cold, and are highly versatile with plenty of recipes available online. Black eyed peas might seem boring, but they pack 8 grams of protein in just 1/2 cup. Like most other beans, they’re also a great source of iron, magnesium, potassium, and B vitamins. Black beans are one of the richest sources of antioxidants and one of the healthiest beans of all beans and legumes. Their dark color indicates their strong antioxidant content and they also have less starch than some other beans.

Nuts & Seeds

Nuts and seeds are low-calorie foods that are rich in fiber and heart-healthy Omega-3 fatty acids. Peanuts are protein-rich, full of healthful fats, and may improve heart health. They contain around 20.5 g of protein per ½ cup. Peanut butter is also rich in protein, with 8 g per tablespoon, making peanut butter sandwiches a nourishing protein snack. Almonds offer 16.5 g of protein per ½ cup. They also provide a good amount of vitamin E, which is great for the skin and eyes. Chia and Hemp seeds are good source of protein that can be used to make smoothies, yogurts, and puddings. Chia seeds contain 2 g of protein per tablespoon whereas Hemp seeds offer 5 g of protein per tablespoon. Pumpkin seeds are one of the most overlooked sources of iron and protein out there, containing 8 gram of protein per 1/4 cup. They also are an excellent source of magnesium as well.

Vegetables & Fruits

Many dark-colored, leafy greens and vegetables like broccoli, spinach, green peas, green beans, Asparagus, kale, mushrooms, baby greens contain protein. Some roots and tubers like potato also provide about 2% protein. Eaten alone, these foods are not enough to meet daily protein requirements, but a few vegetable snacks can increase protein intake, particularly when combined with other protein-rich foods.

The increase in vegetarian and flexitarian diets will certainly assist in curtailing animal protein shortages, aided by innovative ideas surrounding plant proteins.  

Alternative Sources

The food and biotech industries are breaking new grounds to produce innovative protein products. The newly available unconventional sources of protein are Spirulina, a leaf protein and single cell protein like yeast. Future of the global food market depends on these alternative protein sources, considering the rising global warming and increased demand for food. Not only large companies are part of these food innovations, but also are many young start-ups with their new ideas. The future of food is changing and we are looking forward to it. 

Consumers make 60% of their purchase decisions at the shelf. So as consumers continue to hone their specific diets and shopping habits, manufacturers and retailers have a real opportunity to tout protein content right on-pack or with in-store signage, even for products where it seems obvious. Protein can now be found in so many different areas across the store. Some protein powders are plant-based. Depending upon the plants used to make the powders, they may be complete or incomplete proteins. While food supplements can help people meet their daily nutrition goals, eating a wide variety of nutrients rich in protein is usually a better strategy for meeting daily goals. Some protein supplements may also be high in sugar or sodium to improve the taste, so it is important to read the nutrition labels.

The author is A. Professor, Zoology at Miranda House, University of Delhi 

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