Thinking of taking the vegan plunge, like President Bill Clinton, Lea Michelle and Ellen DeGeneres have? A vegan diet — one that excludes all animal foods — is a great idea for your health. But if you’re not careful, you could make some common nutritional mistakes.

Here are seven tips to keep in mind.

1. Be sure to get enough vitamin B12. Most B12 comes from meat and dairy. Plants don’t produce it. Adults need about 2.4 micrograms of B12 every day for healthy blood cells. Without enough of it, you might begin to feel tired and weak, with tingling in your arms or legs. The Physicians Committee for Responsible Medicine suggests you plan to eat foods fortified with B12, such as fortified cereal and some brands of soy milk. Nutritional yeast is another option, according to that group. It’s grown on foods such as molasses or sugar beets. It comes in flake and powder form, and you can cook with it, mix it into your food or just sprinkle it on top. If a blood test shows your B12 is low, you may need a supplement. Talk to your doctor.

2. Seek out iron. You need iron to make red blood cells, but it’s harder for your body to use iron from plant sources than from meat. Lack of iron can make you feel weak, tired and dizzy. Men need 8 milligrams and women need 18 milligrams every day. A cup of fortified cereal will do the trick. Also, try eating your spinach, beans and tofu (fair iron sources) together with a vitamin C-rich food (citrus fruits, strawberries, broccoli, red peppers) to help you absorb the iron.

3. Close the calcium gap. You need calcium for strong bones, and dairy is one of the best sources. But cruciferous veggies such as broccoli and kale also provide some, so fill up. Almonds, Brazil nuts, sunflower seeds and dried beans are other decent sources. And calcium-fortified juice is a sure thing.

4. Make up for missing fish. Fatty fish is an excellent source of heart-healthy omega-3 fatty acids, specifically, types known as docosahexaenoic acid(DHA) and eicosapentaenoic acid (EPA). Vegan omega-3 supplements, made from algae, are one alternative to consider. Ask your doctor whether you could benefit from them, especially if you have an increased risk for heart disease. Another type of omega-3 fatty acid, called alpha-linolenic acid (ALA), is found in soybean and canola oil as well as in flaxseed and walnuts. The body converts ALA to DHA and EPA, though not very efficiently.

5. Avoid packaged foods. Packaged vegan foods, such as frozen bean burritos and microwaveable pasta dishes, can contain large amounts of sugar, sodium and calories. Some manufacturers also use trans fats. Trans fats are cheap and can make foods taste creamier and last longer on the shelf, but they also clog your arteries. The smarter approach: Make fresh produce, whole grains, legumes, nuts and seeds the basis for most of your meals.

6. Don’t over-rely on meat substitutes. Soy is the main ingredient in most meat substitutes. These “faux meats” can be fine choices (though you might want to seek out products that are verified non-GMO if you prefer not to eat genetically modified soy). But when you start to rely heavily on soy hot dogs and soy-based veggie burgers to the exclusion of nutrient-dense veggies, fruits, grains, and proteins, you deprive yourself of a healthy, well-rounded vegan diet.

7. Add variety. There’s no reason going vegan has to mean eating the same bean dish or veggie burger every night. The more variety you introduce, the better the chances you’ll cover all your nutritional bases. Treat yourself to a few vegan cookbooks or find recipes online and develop a roster of dishes you love.