Like a lot of problems, surprisingly: https://www.healthline.com/nutrition/vegetarian-and-vegan-mistakes
The article says you need detailed meal planning to ensure you are getting the nutrients you need when eating plant-based diets.
(I was an accidental vegetarian – see story in right most column. Caused numerous serious health problems and I will not be doing that again. If you choose that lifestyle, let your doctor know and also discuss with a nutritionist/dietician. Vegetarianism is not something you do casually, especially if over age 50 and you intend to do it for a period of time, such as more than 1 year. Talk to an expert.)
