Vegan diets have grown in popularity and so healthcare practitioners need to be adequately educated to be able to give advice, as if they are properly planned, they can give adequate nutrition throughout all stages of life. This review study aimed to summarise the findings of the Scientific Society for Vegetarian Nutrition (SSNV) on vegan diets throughout pregnancy, breastfeeding, infancy, and childhood to provide recommendations for healthcare professionals. The paper starts by defining a well-planned vegan diet as high in a variety of whole or minimally processed plant foods, which meets the required amount of energy. In addition, minimising vegetable fats and avoiding trans fats to not displace other nutrient-dense foods is a requirement of a vegan diet with sufficient nutrition. Adequate amounts of calcium are also needed to be a complete vegan diet and vitamin B12, and vitamin D should be obtained from alternative sources, which are lacking in plant-based diets. The paper then goes on to recommend sources and requirements of protein, fibre, omega-3 fatty acids, iron, zinc, iodine, calcium, vitamin D, and vitamin B12 in vegans during pregnancy, lactation, infancy, and childhood. Many positives of a vegan diet were outlined such as increased fibre benefitting gut bacteria and high iron intakes. It was concluded that adequately planned vegan diets can provide sufficient nutrition at all stages of pregnancy and early life and instances of malnutrition in vegans is usually due to an inappropriate diet. Healthcare professionals could use this paper to understand what defines a complete vegan diet and sources of critical nutrients to ensure that vegan clients and patients are receiving adequate nutrient amounts.