The food we eat can broadly be broken down into three ‘macronutrients’ – proteins, carbohydrates, and fats. A healthy diet needs to consist of an appropriate mix of these nutrients from a variety of sources. 
Dietary protein is absolutely essential for good health. This is because while protein can technically be used as a source of energy, it has a number of vital structural and functional roles.

What is protein, and why is it important?
Protein is a macronutrient that’s made up of amino acids. It's essential for:1,2,3,4,5
Building and repairing tissues (muscles, skin, hair)
Creating enzymes and hormones
Supporting immune function

How much protein do I need? 

Your protein needs depend on your activity level and body weight:
-Sedentary or moderately active adults: 0.8-1 g per kg of body weight
-Very active/athletes or recovering from injury: 1.4-2 g per kg of body weight

For example, an active individual weighing 60 kg needs about 84-120 g of protein daily.

How can I incorporate protein into my diet?

Follow these simple steps:
1. Calculate your protein needs: Multiply your weight in kg by the factor mentioned above according to your activity level to get the amount in grams.
2. Divide this amount over your daily meals.
3. Choose protein sources for each meal in appropriate quantities.

A perfect plate should consist of 25% protein. For example, a 60 kg moderately active person needs about 48-60 g of protein daily. This can be achieved by including 20-30 g of protein in each meal.

Read more about the perfect plate. 

What are good sources of protein?

Protein can be found in both animal and plant-based foods:
Animal sources:
-Meat/fish
-Eggs
-Dairy products

Plant sources:
Legumes (beans, lentils)
Nuts and seeds
Soy products (tofu, tempeh)

Is animal protein better than plant protein?
Animal proteins are generally considered "complete" as they contain all essential amino acids. However, plant proteins can be combined to create complete protein profiles. For example, rice and beans together provide all essential amino acids.

Click here to read more about animal protein and plant protein.

What is protein quality?
Protein quality is measured by the Protein Digestibility-Corrected Amino Acid (PDCAA) score. This score considers the amino acid profile and digestibility of the protein. Higher scores indicate better quality. For instance:
Eggs and milk: 1.0
Whey protein: 1.0
Soy: 0.91
Chickpeas: 0.78
Dal: 0.70

Can I get enough protein on a vegetarian or vegan diet?
Yes, with proper planning. Vegans and vegetarians should aim for the higher end of the recommended protein range and focus on combining different plant proteins to ensure they get all essential amino acids. 

Read more about the vegetarian sources of protein here.  

When should I eat protein?
Distribute your protein intake throughout the day for optimal utilization. Include a source of protein in each meal and snack. Aim for at least 20-25g of protein per meal.

Do I need protein supplements? 

For most individuals, a balanced diet provides an adequate amount of protein. However, athletes, older adults, or those with higher protein requirements may benefit from supplements, such as whey protein, if they are unable to meet their daily protein needs through food.

How does protein help with weight management?
Protein helps control appetite and increases feelings of fullness. It also has a higher thermic effect, meaning your body burns more calories digesting protein compared to fats or carbs.7

What about protein and muscle building?
Adequate protein intake, combined with resistance training, is crucial for muscle growth and repair. Consuming protein after exercise can enhance muscle recovery and growth.8,9

Final words
Protein plays a crucial role in maintaining overall health. It supports vital functions such as muscle and tissue repair, fluid balance, and structural integrity, making it an essential component of daily nutrition. Insufficient protein intake can have negative effects on your health, so it’s worth reevaluating both the quantity and quality of the protein in your diet.

References - 
What are proteins and what do they do? [Internet]. MedlinePlus. U.S. National Library of Medicine; 2021 [cited 2023Feb10]. Available from: https://medlineplus.gov/genetics/understanding/howgeneswork/protein/ 
LaPelusa A, Kaushik R. Physiology, Proteins. InStatPearls [Internet] 2021 Nov 21. StatPearls Publishing.
Yeo J, Jung G, Tarakanova A, Martín-Martínez FJ, Qin Z, Cheng Y, Zhang YW, Buehler MJ. Multiscale modeling of keratin, collagen, elastin and related human diseases: Perspectives from atomistic to coarse-grained molecular dynamics simulations. Extreme Mechanics Letters. 2018 Apr 1;20:112-24.
Busher JT. Serum albumin and globulin. Clinical methods: The history, physical, and laboratory examinations. 1990;3:497-9.
Carlson GP. Fluid, electrolyte, and acid-base balance. InClinical biochemistry of domestic animals 1997 Jan 1 (pp. 485-516). Academic Press.
Nutrient Requirement for Indians. Indian Council of medical research and National institute of Nutrition; 2020 [cited 2023Feb10]. Available from: https://www.nin.res.in/RDA_short_Report_2020.html
Wirunsawanya K, Upala S, Jaruvongvanich V, Sanguankeo A. Whey protein supplementation improves body composition and cardiovascular risk factors in overweight and obese patients: a systematic review and meta-analysis. Journal of the American College of Nutrition. 2018 Jan 2;37(1):60-70.
Rahimi MH, Shab-Bidar S, Mollahosseini M, Djafarian K. Branched-chain amino acid supplementation and exercise-induced muscle damage in exercise recovery: A meta-analysis of randomized clinical trials. Nutrition. 2017 Oct 1;42:30-6.
Xu ZR, Tan ZJ, Zhang Q, Gui QF, Yang YM. The effectiveness of leucine on muscle protein synthesis, lean body mass and leg lean mass accretion in older people: a systematic review and meta-analysis. British Journal of Nutrition. 2015 Jan;113(1):25-34.