Essential amino acids are the building blocks of proteins that cannot be synthesized by the body and must be obtained through diet. There are nine essential amino acids that humans must consume in adequate amounts to maintain optimal health: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

Plant-based diets can provide all of the essential amino acids, but they may require careful planning and a varied diet. Some plant-based sources of protein are not complete proteins, meaning they do not contain all of the essential amino acids in sufficient amounts. For example, grains are generally low in lysine but high in methionine, while legumes are low in methionine but high in lysine. Therefore, combining different plant-based sources of protein can ensure adequate intake of all the essential amino acids.

Some good plant-based sources of protein include:

* Legumes such as lentils, chickpeas, black beans, kidney beans, and soybeans

* Nuts and seeds such as almonds, cashews, chia seeds, pumpkin seeds, and hemp seeds

* Whole grains such as quinoa, oats, brown rice, and whole wheat

* Vegetables such as broccoli, spinach, and peas

It’s important to note that while plant-based sources of protein can provide all the essential amino acids, the quality, and quantity of protein in a vegan or vegetarian diet can vary depending on the individual’s food choices and overall diet. It’s recommended to consult a registered dietitian or healthcare professional to ensure adequate protein intake and overall nutrition on a plant-based diet. There are several potential advantages of plant-based nutrition, including:

1. Reduced risk of chronic diseases: Several studies have shown that a plant-based diet may help reduce the risk of chronic diseases, such as heart disease, diabetes, and certain types of cancer. For example, a review of 12 studies found that individuals following a vegetarian diet had a 25% lower risk of developing heart disease compared to those who consumed meat. (Source: Dinu et al., 2017)

2. Weight management: Plant-based diets may also help with weight management. Studies have found that individuals who follow a vegetarian or vegan diet tend to have a lower body mass index (BMI) and lower rates of obesity compared to those who consume meat. (Source: Turner-McGrievy et al., 2015)

3. Improved gut health: A plant-based diet can also be beneficial for gut health, as it is typically high in fiber and prebiotics, which promote the growth of beneficial gut bacteria. Studies have shown that a plant-based diet can help improve gut microbiota diversity, reduce inflammation, and improve digestive symptoms. (Source: Singh et al., 2021)

4. Environmental sustainability: A plant-based diet may also be more environmentally sustainable, as it requires fewer resources (such as water and land) and generates fewer greenhouse gas emissions compared to a diet high in animal products. (Source: Willett et al., 2019)

Here are a few studies that support these advantages of plant-based nutrition:

* Dinu, M., Abbate, R., Gensini, G. F., Casini, A., & Sofi, F. (2017). Vegetarian, vegan diets and multiple health outcomes: A systematic review with meta-analysis of observational studies. Critical reviews in food science and nutrition, 57(17), 3640-3649.

* Turner-McGrievy, G. M., Davidson, C. R., Wingard, E. E., Wilcox, S., & Frongillo Jr, E. A. (2015). Comparative effectiveness of plant-based diets for weight loss: a randomized controlled trial of five different diets. Nutrition, 31(2), 350-358.

* Singh, R. K., Chang, H. W., Yan, D., Lee, K. M., Ucmak, D., Wong, K., … & Sinha, S. R. (2021). Influence of diet on the gut microbiome and implications for human health. Journal of translational medicine, 19(1), 1-26.

* Willett, W., Rockström, J., Loken, B., Springmann, M., Lang, T., Vermeulen, S., … & Murray, C. J. L. (2019). Food in the Anthropocene: the EAT–Lancet Commission on healthy diets from sustainable food systems. The Lancet, 393(10170), 447-492.