Week Two:

You will have noticeably increased energy, and you’re likely to see some slight weight loss, because your overall calorie intake has likely gone down. “Not much weight loss,” says Levin. “We don’t want people dropping weight like crazy.” With increased energy, she says, you will find your workouts getting better and, as pro athletes have noted, your recovery time will become shorter. By the end of your second week, says vegan ultramarathoner Scott Jurek, you won’t feel as achy after your workouts.

With more energy, says Levin, comes a brighter mood and outlook. According to a 2009 Arizona State University study, people who cut all meat from the diets, including fish, showed less tension and stress.

Week Three:

“Enjoy everything you had in week two, but even more energy and probably a final layer of weight loss,” says Levin. But really, this week is where it gets molecular. “If you were someone who was meticulous and into blood labs, you’d actually see your blood sugars and cholesterol levels go down,” says Levin. “Your blood pressure will also fall as you’re breathing better and your arteries are clearing out.”

III. Your New Shopping List

“Eating organic, whole foods does not have to be expensive,” says Jurek. “Put your dollars in fresh produce and bulk foods. The less packaged food you eat, the more you will save, and the quality of your diet will increase. And get out and explore your local farmers market.”

Protein:

These will ensure you get plenty of it.

• Firm tofu: It’s easier to treat firm tofu like meat when cooking. It doesn’t break down as easily as soft tofu, which is mainly used in dips and desserts.

• Tempeh: a great ground-meat substitute for tacos and bolognese sauce

• Beans: black or pinto — no refried beans because of the lard

• Hemp or rice milk: better than soymilk, which is heavily processed

• Nuts: Nuts are a rich source of protein but often high in fat. However, it’s unsaturated fat, which may help lower cholesterol. Cashews are great for snacks between meals and when cooking Asian dishes. Pine nuts are ideal for salads.

• Almond butter: This is your peanut butter substitute. (PB is vegan, but almond butter is better for you.) Use it for sandwiches or on toast to add protein to your breakfast. We like Once Again, found in most health-food stores; Nature’s Promise, from Stop & Shop’s organic food line; and the Trader Joe’s brand.

• Hemp or brown-rice protein: for your smoothies and to sprinkle on salads

Vegetables and Fruits:

This is your new meat, not in terms of protein, but in terms of the real centerpiece of your daily meals and snacks. So go to town. Below is a list of particularly versatile options, some that pack more nutrients and proteins per gram than any others.

• Broccoli: At thirty-three percent protein, broccoli fills you up and keeps you full.

• Spinach: This is where you get your calcium now that you’ve given up milk. It’s also packed with antioxidants.

• Avocadoes: bursting with vitamins, 18 amino acids and omega-3 and -6 fatty acids, which help lubricate joints and reduce inflammation

• Kale: This “superplant” is rich in phytochemicals sulforaphane and indoles, which research suggests protects against cancer.

• Yams and sweet potatoes: staples of the vegan diet for their density and carbs

• Leafy greens: any of the lettuces: romaine, arugula, and watercress, plus bok choy, collard greens, and artichokes

• Tomatoes, cucumbers, and carrots: for salads, sandwiches, and snacking

• Blueberries, strawberries, and raspberries: for smoothies, snacks, and breakfast cereals

Grains, Seeds, and Cereals:

• Quinoa

• Brown rice

• Whole-wheat bread: preferably from a bakery

• Steel-cut oats: The inner parts of the oat kernel, much less processed than rolled oats or old-fashioned oatmeal. Great for a hearty fall or winter breakfast.

• Chia seeds: This new vegan fad food is the offspring of those claymate Chia Pet sproutings. It was the main source of fuel for Aztec warriors and has recently caught on with the health crowd, thanks to its superfood qualities. Chia seeds are packed with protein, omega-3 and -6 fatty acids, and soluble fiber, which helps stabilize blood-glucose levels. Bake them into cookies or eat them by the handful.

• Granola: Some granola may contain eggs, honey, or other non-vegan ingredients, so be careful.

• Whole grain-based cereals: like Kashi brand

Vegan Energy Bars: Your best friends at the airport, long car rides, and between office meetings. Here are some of the best.

• Vega bars: Triathlete Brendan Brazier concocted these himself. His entire Vega food line is worth checking out.

• ProBar

• Kind Bar

• Raw Revolution

• 18 Rabbits

Supplements: If you’re superathletic and working on strength training, you can build your daily protein intake by adding these to your shakes, cereals, or salads.

• Hemp protein

• Brown-rice protein

Ready-made meals: This is all cook-and-eat food. Have a few of these in your fridge or freezer for those late work nights when you can’t prepare anything yourself.

• Field Roast: Its Celebration Roast is great for a large party or days of leftovers.

• Gardein: Everything from meatless buffalo wings and ribs to “Chick’n Scaloppini.”

• Turtle Island Foods: Creator of the much-mocked holiday Tofurky, it also makes Tofurky pizza.