When some people decide to give up meat, they still want something that looks, smells and tastes like meat on their plate—and they want its preparation to be as easy as flipping a burger on the grill. Even mainstream supermarkets now offer dozens of protein-rich products to fill this savory niche, usually made from some combination of textured or hydrolyzed soy protein, wheat gluten, grains and tofu.

Great idea, right? Not necessarily. It may be convenient to rely on “meat analog” products when first making the transition to a plant-based diet, but a steady diet of them isn’t healthy, say nutritionists, because these products often have similar problems as other highly refined foods. Too many vitamins and minerals are leached away during production; plus, they often contain an unwholesome amount of salt, flavorings, colorings and other chemicals to make them palatable.

“They’re really not ideal foods, long-term,” states Brendan Brazier, an Ironman triathlete and author of The Thrive Diet and Thrive Fitness. “After the transition is made, I tell people to cut these highly processed things out drastically—even cut them out completely.”

Mitzi Dulan agrees. She’s a registered dietitian and team nutritionist for the Kansas City Royals (and formerly with the Kansas City Chiefs) and co-author, with NFLer Tony Gonzalez, of The All-Pro Diet. Dulan tells vegan clients to seek their protein in beans and other legumes, nuts, whole grains and naturally fermented soy foods like tempeh; if they want to buy vegan products, they should make sure they’re made from these whole-food ingredients.

Remarks Dulan, “I’d prefer to see people stay away from those fake meats and cheeses.”