That said, whole-food sources of soy, like edamame and tofu, along with legumes and grains like quinoa, can provide plenty of the protein you need. Still, even nutrition professionals find vegan diets hard to regulate. Elite runner and personal chef Devon Crosby Helms, 30, felt "fantastic" for the first six months of her vegan diet. However, because she was already gluten-, bean-, and soy-free (due to allergies), nixing meat was the tipping point to poor health. Suffering from "overwhelming and constant fatigue, muscle loss, and weight gain," Crosby Helms' doctor diagnosed her with hypo-thyroidism, adrenal fatigue, and anemia. With limited food choices, "being vegan created a great deal of anxiety," she says.
Indeed, "totally revamping your diet requires an intense mental adjustment. Any diet that requires you to cut out entire food groups will generally trigger cravings," explains Susan Albers, a clinical psychologist who specializes in eating disorders at the Cleveland Clinic in Cleveland, Ohio. "An extreme diet [of any kind] can often trigger disordered eating and sometimes even an eating disorder." During 26-year-old Pamela Stubbart's final six months as a vegan, the NYC resident experienced blood sugar spikes and intense cravings. "I couldn't focus on anything else but whether or not to eat an egg. It would go on for hours," she says.
For others, going vegan can pay off, initially at least. A vegan for almost two years, Susan Stella Floyd, 33, from Austin, Texas, lost 10 pounds within the first two months. But three months later she regained the weight--and 10 more pounds. She partially blames her "very carb-heavy diet." And while veganism promises healthy cholesterol, Floyd's levels were borderline high. Because a vegan diet may lack appropriate amounts of good fat (like omega-3's and vitamin B12), some vegans may suffer from elevated levels of the amino acid homocysteine (associated with blood vessel damage) and lower HDL (aka good) cholesterol. Both, notes one 2011 study, can actually increase the risk for heart problems and stroke.
After reading books on veganism and working at a health foods store, Bonnie Farrell, 26, from Portland, Maine, figured she was prepared to go vegan. She ate mostly raw foods and also started to bike everywhere. A diet consisting mainly of fruits, veggies, nuts, and seeds, combined with the sudden rigorous exercise, helped her drop 25 pounds. "I took it as a sign that my body was thriving," she says. Instead, the opposite was happening. Her energy levels would skyrocket, only to crash and leave her extremely fatigued. She became consumed by near daily panic attacks. Rounds of testing with two different doctors revealed a deficiency of several vitamins and minerals. Her adrenal system, which regulates stress, had "burnt out"; her thyroid was malfunctioning. "I felt like my body was locked in a prison," Farrell says.