If you’re eating a vegetarian or vegan diet because you think it’s better for your health, you might want to avoid those meat substitutes that are popping up everywhere – even at popular fast food joints.

Because even if they don’t contain meat, they contain plenty of other stuff that might be just as bad for you as a regular burger.

Recent studies do support the fact that eating plant-based diets has a positive impact on the planet, but there is still much research that needs to be done on the nutritional value of plant-based meat substitutes.

Recently, a study from Chalmers University of Technology in Sweden worked to close some of those gaps and analyze the nutritional contents of different meat alternatives.

What they found isn’t good, if health is your main concern in adopting a plant-based diet, according to lead author Cecilia Mayer Labba.

“Among these products, we saw a wide variation in nutritional content and how sustainable they can be from a health perspective. In general, the estimated absorption of iron and zinc from the products was extremely low. This is because these meat substitutes contained high levels of phytates, antinutrients that inhibit the absorption of minerals in the body.”

Phytates, or phytic acid, are found in seeds, nuts, grains, and legumes, and they bind to certain minerals in the digestive tract to block their absorption in the intestine. This can lead to mineral deficiencies over time, especially in people who are already lacking nutrition.

“Both iron and zinc also accumulate in protein extraction. This is why high levels are listed among the product’s ingredients, but the minerals are bound to phytates and cannot be absorbed and used by the body.”

The team analyzed 44 meat substitutes and published their findings.

“None of the products could be regarded as a good source of iron due to very high content of phytate…and/or low content of iron. Tempeh performed the best for iron, having a content similar to that claimed on the packaging, and was found to have a lower phytate content.”

Though the authors seem to be less than impressed by meat-substitute products in general, they don’t suggest people avoid them, but instead just ensure they are getting their recommended intake of iron from other sources.

“We believe that making nutrition claims on only those nutrients that can be absorbed by the body could create incentives for the industry to improve those products.”

And hey, if you’re looking for a business opportunity, plant-based meat could be where it’s at.

“Plant-based food is important for the transition to sustainable food production, and there is a huge development potential for plant-based meat substitutes.”