Potential Downsides A well-rounded vegetarian diet can be healthy and nutritious. However, it may also increase your risk of certain nutritional deficiencies. Meat, poultry and fish supply a good amount of protein and omega-3 fatty acids, as well as micro nutrients like zinc, selenium, iron and vitamin B12 . Other animal products like dairy and eggs also contain plenty of calcium, vitamin D and B vitamins . When cutting meat or other animal products from your diet, it’s important to ensure you’re getting these essential nutrients from other sources.