What is nutrition and what does the science say?
The two major components of excellent health are nutrition and exercise. Nutrition is a science dealing with the components of food and how they interact with the body. Many controversies surround human nutrition but a majority of scientific data point in one general direction. Plant-based diets are healthy as long as a variety of different whole foods are eaten and energy needs are met.
Below are dietary models of balanced meals, which can include or exclude animal products. If you choose to be a vegetarian or vegan, then there is no need to have any chicken, fish, dairy or any other animal product for protein. Eating a variety of beans, whole grains, and nuts can ensure that you get high quality protein and minerals similar to those found in animal protein. Vitamin B 12 is made by bacteria in the soil and most whole plant foods do not have enough after being transported and washed so eat fortified foods or supplements if you are vegan. Eating a large portion of calories from animal foods like beef, eggs, or cheese can lead to deadly diseases like heart disease or cancer.
How do we know what to eat?
In general we are told to choose from different food groups. The Harvard School of Public Health has helpful and easy-to-understand nutrition information. The Healthy Eating Plate model that Harvard has is simple yet highly informative. The four sections include the largest portion for vegetables, a small portion for fruit, a quarter for protein and a quarter for whole grains. The advantages of the Harvard model include more descriptions of types of food to eat or to avoid and the exclusion of milk at every meal. In fact, Harvard’s New Guide to Healthy Eating says, “Limit milk and dairy products to one to two servings per day, since high intakes are associated with increased risk of prostate cancer and possibly ovarian cancer.” Some alternatives to milk are calcium-fortified soy milk or almond milk (low in protein) or calcium-rich green leafy vegetables such as kale, broccoli, spinach, and collards.
The American dietary model updated in 2010 includes MyPlate, which is a plate with four sections including fruits, vegetable, grains, and protein (www.choosemyplate.gov). This is an enormous improvement from the past diet model called MyPyramid. The Dietary Guidelines 2010 for Americans is a 95 page set of recommendations that is difficult and ambiguous for most people to follow. However, there are many interesting and beneficial topics covered in this material, such as the definition of a refined grain or whole grain, limiting cholesterol to 300 mg per day, etc.
From the United States Department of Agriculture website: ChooseMyPlate.gov