Posted by Star the magic vegan at 01/23/17 08:42:14A vegan diet is perfect for you. Just take organic vitamin B sublingual you squirt under your tongue in a synthetic form, nutritional yeast sprinkled on all your food and an organic, plant based vegan D3 vitamin daily. These are the only supplements you need. If you work with a state licensed herbalist doctor, you might find that simple over the counter saffron pills will increase your appetite if you need to gain weight. 680 calories is very much on the light side, try going up to 1000 calories at least. Working with a vegan nutritionist and a doctor always is a smart idea. Vegan food is also high in complex carbohydrates which boosts the immune system and that is important if you are underweight.