Can a vegan diet (a no-meat, no-eggs, no dairy way of eating) be healthy? It can be, says American Dietetic Association spokesperson Keri Gans, but only if you're willing to do your homework.

You can't exist solely on salads and soy milk. And you can't eat too many carbohydrates or excess amounts of nuts and seeds. A poorly planned vegan diet can lead to unhealthy weight loss or weight gain and can fall short on key nutrients too. Here's what you don't want to miss out on.

Protein
Plant foods will work but you should eat a variety of foods, including whole grains, beans, and nuts to replace the proteins in meat, milk, and eggs.

Calcium
Milk and cheese contain a lot of calcuim so if you plan to give these items up, pump up the dark, leafy green vegetables, such as broccoli and add to your diet some figs, almonds, and soy foods. Most vegans need fortified foods (such as soy milk or orange juice) and a supplement to get enough calcium.

Vitamin D
When the main source of D -- that would be milk -- is cut out, the sun can come in handy, although it's nothing to bank on for those in winter climates and those who are dark-skinned. A supplement or fortified foods are essential for this one too.

Vitamin B-12
Break out the fortified foods and a supplement once again since this essential vitamin is available only in animal foods.

In sum, a basic multivitamin and a good variety of fruits, vegetables, whole grains, nuts, seeds, and a few fortified products can cover the vegan bases. So, yes, a vegan diet can be healthy. It just takes commitment, research, and a lot of practice.