12 Things You Need To Know Before Going Vegan

"People are very sensitive about their diets, especially when you challenge what they have always believed," says plant-based dietitian Julieanna Hever, RD, host of Veria Living's "What Would Julieanna Do?" "The best way to minimize conflict is to emphasize that you are going vegan for your own reasons and that it seems to work for you. In other words, make it about you, so nobody feels they need to defend their choices."

Vitamin B12 occurs naturally only in animal foods, so you'll want to stock up on a variety of B12-fortified foods as well as a B12 supplement. B12 keeps the body's nerve and blood cells healthy and helps make DNA, so deficiencies can lead to tiredness, weakness, constipation, loss of appetite, weight loss (the bad kind), nerve problems, and depression. To find out if you need to up your intake, ask your doctor for a simple blood draw.

Iron comes in two forms: heme and non-heme. Heme, which makes up about 40 percent of the iron in animal foods, is easily absorbed by the body. Vegan diets contain only non-heme, which is less readily absorbed, so you may need to ingest more iron if you want to get the same benefit, says New York City nutritionist Christian Henderson, RD. Good vegan iron sources include legumes, sunflower seeds, dried raisins and dark, leafy greens. Vitamin C-rich foods (think: red peppers, citrus and broccoli) aid iron absorption.

Every meal should contain protein, says vegan dietitian Valerie Rosser, RD. Proteins are the building blocks of life: they break down into amino acids that promote cell growth and repair. The Institute of Medicine recommends that adults get at least 0.8 grams of protein daily for every kilogram of body mass -- that's about 54 grams for a 150-pound woman. The best sources of vegan protein include natural soy, lentils, beans, quinoa and seitan, Rosser says.

Swapping out meat for white bread, pasta and other packaged foods sets you up for failure on the vegan diet, says Rosser. "It's not a good idea to trade in animal products, which contain protein, vitamins and minerals, for processed foods that provide little nutritional value other than calories." The result: hunger, weight gain and a grumpier mood.

In general, critics overstate the dangers of soy and the promoters exaggerate its benefits. Though scientists are still arguing over the effects of soy on cancer and heart health, one thing is for certain: "Consuming too much soy-based vegan 'meat' is arguably worse than consuming high-quality animal products," says Henderson. Meat substitutes are often highly processed and loaded with sodium and preservatives, so read labels carefully. The healthiest sources of soy are miso, tempeh, tofu, soy milk and edamame.

You won't just wake up one morning magically vegan. It takes work, so it should also take time, Henderson says. "Start by adding more plant-based foods to your diet, while at the same time cutting back on animal products, especially those that are non-organic, and more importantly processed, refined foods. Making gradual changes and assessing how you are feeling along the way is key," she says.

If you're serious about being vegan, checking food labels and verifying ingredients is a must. "Just because a food product is not glaringly non-vegan doesn't mean that it's suitable for a vegan diet," Rosser says. Casein and whey, which come from milk, are present in many cereal bars, breads and granolas, while gelatin and tallow (also known as suet) are derived from meat. Then there's Natural Red 4 (also known as carmine, cochineal or cochineal extract), which is a food coloring derived from the dried bodies of female beetles. Head spinning yet? The Vegetarian Resource Group's list of common food ingredients can help.

Animals won't be the only ones happy with your vegan move. So will you. One reason why: Compared to vegetarian diets, omnivorous ones contain more arachidonic acid, which can spur neurological changes that drag down mood, according to a 2012 Nutrition Journal study.

Just as veganism is becoming more popular, so are vegan options on just about every restaurant's menu. Word to the wise: Even if your item of choice looks vegan, tell your waiter about your dietary restriction to ensure that no animal products are used to make your meal (think hidden butter or chicken stock), Henderson advises. And if you are up for trying an all-vegan restaurant, check out veganrestaurantfinder.com.

At $3 or more per pound, meat is one of the most expensive items in the grocery store, so saving big can be easy -- even if you are buying more produce than ever. Save even more by swapping some of your fresh produce for frozen.

The NIH recommends that adults between the ages of 19 and 50 get a minimum of 1,000 mg of calcium a day, but preliminary research shows vegans may be able to get away with less than that. A European Journal study found that when vegans consumed at least 525 mg per day of calcium, their risk of bone fracture was no different than that of non-vegetarians with similar calcium intakes. The key is eating a variety of naturally calcium-rich foods such as kale, bok choy, almonds, soy beans, figs and navel oranges as well as calcium-fortified foods such as cereals, plant-based milks and tofu made with calcium sulfate, Henderson says. Bonus: soy, leafy greens and most fortified foods are also high in vitamin D, which helps your body absorb calcium.